<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE article PUBLIC "-//NLM//DTD Journal Archiving and Interchange DTD v2.3 20070202//EN" "archivearticle.dtd">
<?covid-19-tdm?>
<article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" article-type="systematic-review">
<front>
<journal-meta>
<journal-id journal-id-type="publisher-id">Front. Psychol.</journal-id>
<journal-title>Frontiers in Psychology</journal-title>
<abbrev-journal-title abbrev-type="pubmed">Front. Psychol.</abbrev-journal-title>
<issn pub-type="epub">1664-1078</issn>
<publisher>
<publisher-name>Frontiers Media S.A.</publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.3389/fpsyg.2020.624567</article-id>
<article-categories>
<subj-group subj-group-type="heading">
<subject>Psychology</subject>
<subj-group>
<subject>Systematic Review</subject>
</subj-group>
</subj-group>
</article-categories>
<title-group>
<article-title>Impact of COVID-19 Pandemic on University Students&#x00027; Physical Activity Levels: An Early Systematic Review</article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name><surname>L&#x000F3;pez-Valenciano</surname> <given-names>Alejandro</given-names></name>
<xref ref-type="aff" rid="aff1"><sup>1</sup></xref>
<xref ref-type="aff" rid="aff2"><sup>2</sup></xref>
<uri xlink:href="http://loop.frontiersin.org/people/529986/overview"/>
</contrib>
<contrib contrib-type="author" corresp="yes">
<name><surname>Su&#x000E1;rez-Iglesias</surname> <given-names>David</given-names></name>
<xref ref-type="aff" rid="aff3"><sup>3</sup></xref>
<xref ref-type="corresp" rid="c001"><sup>&#x0002A;</sup></xref>
<uri xlink:href="http://loop.frontiersin.org/people/857068/overview"/>
</contrib>
<contrib contrib-type="author">
<name><surname>Sanchez-Lastra</surname> <given-names>Miguel A.</given-names></name>
<xref ref-type="aff" rid="aff4"><sup>4</sup></xref>
</contrib>
<contrib contrib-type="author">
<name><surname>Ay&#x000E1;n</surname> <given-names>Carlos</given-names></name>
<xref ref-type="aff" rid="aff5"><sup>5</sup></xref>
<uri xlink:href="http://loop.frontiersin.org/people/65285/overview"/>
</contrib>
</contrib-group>
<aff id="aff1"><sup>1</sup><institution>Observatory of Healthy &#x00026; Active Living of Spain Active Foundation, Centre for Sport Studies, King Juan Carlos University</institution>, <addr-line>Madrid</addr-line>, <country>Spain</country></aff>
<aff id="aff2"><sup>2</sup><institution>GO Fit LAB, Ingesport</institution>, <addr-line>Madrid</addr-line>, <country>Spain</country></aff>
<aff id="aff3"><sup>3</sup><institution>VALFIS Research Group, Institute of Biomedicine (IBIOMED), Faculty of Physical Activity and Sports Sciences, University of Le&#x000F3;n</institution>, <addr-line>Le&#x000F3;n</addr-line>, <country>Spain</country></aff>
<aff id="aff4"><sup>4</sup><institution>Department of Special Didactics, Faculty of Education and Sport Science, University of Vigo</institution>, <addr-line>Pontevedra</addr-line>, <country>Spain</country></aff>
<aff id="aff5"><sup>5</sup><institution>Well-Move Research Group, Galicia Sur Health Research Institute (IIS Galicia Sur), Department of Special Didactics, Faculty of Education and Sport Science, University of Vigo</institution>, <addr-line>Pontevedra</addr-line>, <country>Spain</country></aff>
<author-notes>
<fn fn-type="edited-by"><p>Edited by: Tommy Langseth, University of South-Eastern Norway, Norway</p></fn>
<fn fn-type="edited-by"><p>Reviewed by: Khaled Trabelsi, University of Sfax, Tunisia; Hamdi Chtourou, University of Sfax, Tunisia</p></fn>
<corresp id="c001">&#x0002A;Correspondence: David Su&#x000E1;rez-Iglesias <email>dsuai&#x00040;unileon.es</email></corresp>
<fn fn-type="other" id="fn001"><p>This article was submitted to Movement Science and Sport Psychology, a section of the journal Frontiers in Psychology</p></fn></author-notes>
<pub-date pub-type="epub">
<day>15</day>
<month>01</month>
<year>2021</year>
</pub-date>
<pub-date pub-type="collection">
<year>2020</year>
</pub-date>
<volume>11</volume>
<elocation-id>624567</elocation-id>
<history>
<date date-type="received">
<day>31</day>
<month>10</month>
<year>2020</year>
</date>
<date date-type="accepted">
<day>07</day>
<month>12</month>
<year>2020</year>
</date>
</history>
<permissions>
<copyright-statement>Copyright &#x000A9; 2021 L&#x000F3;pez-Valenciano, Su&#x000E1;rez-Iglesias, Sanchez-Lastra and Ay&#x000E1;n.</copyright-statement>
<copyright-year>2021</copyright-year>
<copyright-holder>L&#x000F3;pez-Valenciano, Su&#x000E1;rez-Iglesias, Sanchez-Lastra and Ay&#x000E1;n</copyright-holder>
<license xlink:href="http://creativecommons.org/licenses/by/4.0/"><p>This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.</p></license>
</permissions>
<abstract><p><bold>Purpose:</bold> This systematic review aimed to analyze the impact that the COVID-19 lockdown had on the amount of physical activity performed by university students.</p>
<p><bold>Materials and Methods</bold>: A systematic electronic search for studies providing information regarding physical activity levels pre and during COVID-19 pandemic in university students was performed up to 20th October 2020 in the databases Cochrane Library, PubMed, SPORTDiscus, and Web of Science. The risk of bias of external validity quality of included studies was assessed by means of those the Newcastle-Ottawa Scale (NOS). The quality of the evidence for main outcomes was graded using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.</p>
<p><bold>Results and Conclusions</bold>: A total of 10 studies were selected. Physical activity levels were assessed by means of questionnaires (10 studies) and accelerometer (1 study). Risk of bias was regarded as low and high in six and four investigations, respectively. The quality of evidence was downgraded to low. A significant reduction of physical activity levels were observed in 9 studies. Compared to pre-lockdown values, five studies showed a reduction of light/mild physical activity (walking) between 32.5 and 365.5%, while seven studies revealed a reduction of high/vigorous physical activity between 2.9 and 52.8%. Walking, moderate, vigorous, and total physical activity levels have been reduced during the COVID-19 pandemic confinements in university students of different countries. Despite of the reductions, those who met the current minimum PA recommendations before the lockdown generally met the recommendations also during the confinements.</p></abstract>
<kwd-group>
<kwd>COVID-19</kwd>
<kwd>physically active lifestyle</kwd>
<kwd>undergraduate students</kwd>
<kwd>college students</kwd>
<kwd>tertiary education</kwd>
<kwd>lockdown</kwd>
<kwd>confinement</kwd>
<kwd>quarantine</kwd>
</kwd-group>
<counts>
<fig-count count="1"/>
<table-count count="3"/>
<equation-count count="0"/>
<ref-count count="56"/>
<page-count count="10"/>
<word-count count="7322"/>
</counts>
</article-meta>
</front>
<body>
<sec sec-type="intro" id="s1">
<title>Introduction</title>
<p>The world is experiencing a life-threating situation due to the COVID-19 pandemic. By 14th October 2020, there have been 37.888.384 confirmed cases, including 1.081.868 deaths (World Health Organization, <xref ref-type="bibr" rid="B55">2020a</xref>). We still do not have silver bullets or shortcuts, and the answer requires to use every single tool in the toolbox (World Health Organization, <xref ref-type="bibr" rid="B56">2020b</xref>). To this purpose, one of the most important strategies is to reduce mixing of susceptible and infectious people through early ascertainment of cases or reduction of contact (i.e., social distancing; Lewnard and Lo, <xref ref-type="bibr" rid="B37">2020</xref>), implementing measures such as quarantines and lockdowns, which have proven highly effective in controlling the spread of the disease (Baker et al., <xref ref-type="bibr" rid="B8">2020</xref>). These extreme measures, nevertheless, not only have economic consequences (Bonaccorsi et al., <xref ref-type="bibr" rid="B13">2020</xref>). Changes in lifestyle such as reduced physical activity (PA) and unhealthy diet (Ammar et al., <xref ref-type="bibr" rid="B4">2020a</xref>), as well as compulsory measures such as social distance derived from the lockdowns, can also affect both the physical and the mental health of the population worldwide (Ammar et al., <xref ref-type="bibr" rid="B5">2020b</xref>; Mattioli et al., <xref ref-type="bibr" rid="B41">2020</xref>).</p>
<p>Physical inactivity is considered as another pandemic by itself (Hall et al., <xref ref-type="bibr" rid="B30">2020</xref>). It is a major cause of non-communicable chronic diseases, responsible for more than three million premature deaths per year worldwide (Lee et al., <xref ref-type="bibr" rid="B36">2012</xref>; Lim et al., <xref ref-type="bibr" rid="B38">2012</xref>) and the conservatively estimated cost for the healthcare systems was $53.8 billion dollars in 2013 (Ding et al., <xref ref-type="bibr" rid="B22">2016</xref>). Before the COVID-19 outbreak, globally, 23% of adults and 81% of adolescents (aged 11&#x02013;17 years) did not meet the World Health Organization global recommendations on PA for health (World Health Organization, <xref ref-type="bibr" rid="B54">2018</xref>), and the trend was that physical inactivity was not increasing, while it was time spent on sedentary behavior (Guthold et al., <xref ref-type="bibr" rid="B28">2018</xref>; Du et al., <xref ref-type="bibr" rid="B23">2019</xref>).</p>
<p>Previous studies have identified an increase in physical inactivity during the transition from adolescence to adulthood and throughout the college/university years (Bray and Born, <xref ref-type="bibr" rid="B14">2004</xref>; Jung et al., <xref ref-type="bibr" rid="B33">2008</xref>; Crombie et al., <xref ref-type="bibr" rid="B20">2009</xref>; Pullman et al., <xref ref-type="bibr" rid="B45">2009</xref>; Kwan et al., <xref ref-type="bibr" rid="B35">2012</xref>). Pengpid et al. (<xref ref-type="bibr" rid="B44">2015</xref>) estimated that prevalence of physical inactivity among university students in 23 low, middle and high-income countries was 41%.</p>
<p>Social distancing and confinements have largely altered the lifestyle of university students, and it is not clear how the changes in the aforementioned factors are affecting the PA levels of this population. This review aimed to analyze if the PA levels of university students changed during the confinements and their adherence to the current global PA recommendations. Despite existing recommendations, suggesting several potential tactics (i.e. home-based exercise, dance, yoga) to keep active during the lockdown that are available to young populations (Chtourou et al., <xref ref-type="bibr" rid="B19">2020</xref>), we hypothesized that total PA levels would be reduced due to the confinement.</p>
</sec>
<sec sec-type="methods" id="s2">
<title>Methods</title>
<p>This systematic review was carried out following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines (Moher et al., <xref ref-type="bibr" rid="B42">2009</xref>). The PRISMA checklist is presented in Appendix 1 (<xref ref-type="supplementary-material" rid="SM1">Supplementary Material</xref>).</p>
<sec>
<title>Search Strategy</title>
<p>A systematic computerized search was conducted up to 20th October 2020 in the databases Cochrane Library, PubMed, SPORTDiscus and Web of Science, following search terms included in Boolean search strategies: (coronavirus OR COVID-19 OR lockdown) AND (physical activity OR exercise OR activity) AND (university OR college OR student). Finally, the reference lists of the studies recovered were hand-searched to identify potentially eligible studies not captured by the electronic searches. Search strategies can be found in online Appendix 2 (<xref ref-type="supplementary-material" rid="SM2">Supplementary Material</xref>).</p>
<p>Two reviewers independently (AL-V and DS-I): (a) screened the title and abstract of each reference to locate potentially relevant studies, and once hard copies of the screened documents were obtained; (b) reviewed them in detail to identify articles that met the selection criteria. A third external reviewer (CA) was consulted to resolve discrepancies between reviewers in the studies selection.</p>
</sec>
<sec>
<title>Study Selection</title>
<p>To be included in this systematic review studies had to fulfill the following criteria: (1) studies had to report PA levels pre and during COVID-19 pandemic in university students; (2) studies had to assess PA level through a valid and reliable tool; (3) studies had to be published in a peer-reviewed journal before 20th October 2020; (4) studies had to be written in English or Spanish. Literature reviews, abstracts, editorial commentaries, and letters to the editors were excluded.</p>
</sec>
<sec>
<title>Risk of Bias and Quality of the Evidence</title>
<p>Two reviewers independently assessed the risk of bias of external validity quality of included studies using the &#x0201C;Newcastle-Ottawa Scale (NOS)&#x0201D; for cohort studies. The original NOS is a quality assessment tool for cohort and case-control studies which contains eight items categorized into three domains (selection, comparability and exposure) and uses a star rating system to indicate the quality of a study (one star for each item within the Selection and Outcome categories, and a maximum of two stars in Comparability category) (Wells et al., <xref ref-type="bibr" rid="B53">2012</xref>). NOS scores categorized into three groups: very high risk of bias (0&#x02013;3 NOS points), high risk of bias (4&#x02013;6), and low risk of bias (7&#x02013;9) (Lo et al., <xref ref-type="bibr" rid="B39">2014</xref>).</p>
<p>The quality of the evidence for main outcomes was graded (high, moderate, low, or very low certainty) using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Four different GRADE factors were used in this meta-analysis: risk of bias, inconsistency, indirectness and imprecision (Guyatt et al., <xref ref-type="bibr" rid="B29">2011</xref>). The starting point was always the assumption that the pooled or overall result was of high quality. The quality of evidence was subsequently downgraded by one or two levels per factor to moderate, low, or very low when there is a risk of bias, inconsistency, imprecision or indirect results (Balshem et al., <xref ref-type="bibr" rid="B9">2011</xref>).</p>
<p>In order to assess the inter-coder reliability of the coding process, two researchers coded all studies (including risk of bias and quality of the evidence assessment). The inconsistencies between the two coders were resolved by consensus, and when these were due to ambiguity in the coding book, this was corrected. As previously mentioned, any disagreement was resolved by mutual consent in consultation with a third reviewer.</p>
</sec>
</sec>
<sec sec-type="results" id="s3">
<title>Results</title>
<sec>
<title>Descriptive Characteristics of the Studies</title>
<p>One thousand one hundred thirty-seven references were identified after search process in four databases, of which 10 (&#x000C1;cs et al., <xref ref-type="bibr" rid="B2">2020</xref>; Barkley et al., <xref ref-type="bibr" rid="B10">2020</xref>; Gall&#x000E8; et al., <xref ref-type="bibr" rid="B25">2020</xref>; Gallo et al., <xref ref-type="bibr" rid="B26">2020</xref>; Karuc et al., <xref ref-type="bibr" rid="B34">2020</xref>; Maher et al., <xref ref-type="bibr" rid="B40">2020</xref>; Romero-Blanco et al., <xref ref-type="bibr" rid="B46">2020</xref>; Sa&#x000F1;udo et al., <xref ref-type="bibr" rid="B47">2020</xref>; Savage et al., <xref ref-type="bibr" rid="B48">2020</xref>; Alarc&#x000F3;n Meza and Hall-L&#x000F3;pez, <xref ref-type="bibr" rid="B3">2021</xref>) met the inclusion criteria. <xref ref-type="fig" rid="F1">Figure 1</xref> shows the flow chart of the selection process of the studies. The main characteristics of the studies included in this systematic review are presented in <xref ref-type="table" rid="T1">Table 1</xref>. Two studies were carried out in Spain, two in The United States of America, one in Australia, one in Croatia, one in England, one in Hungary, one in Italy and one in Mexico. The total sample size was larger than 3,500 university students.</p>
<fig id="F1" position="float">
<label>Figure 1</label>
<caption><p>Systematic literature review process.</p></caption>
<graphic xlink:href="fpsyg-11-624567-g0001.tif"/>
</fig>
<table-wrap position="float" id="T1">
<label>Table 1</label>
<caption><p>Characteristics of the included studies in the review.</p></caption>
<table frame="hsides" rules="groups">
<thead><tr>
<th valign="top" align="left"><bold>Study and Country</bold></th>
<th valign="top" align="left"><bold>Design (type study/registration time/assessment)</bold></th>
<th valign="top" align="left"><bold>Final sample</bold></th>
<th valign="top" align="left"><bold>PA assessment tool</bold></th>
<th valign="top" align="left"><bold>Severity of restricted internal movement by country</bold></th>
<th valign="top" align="left"><bold>Levels of PA pre COVID-19 lockdown</bold></th>
<th valign="top" align="left"><bold>Levels of PA during COVID-19 lockdown</bold></th>
<th valign="top" align="left"><bold>Other results</bold></th>
</tr>
</thead>
<tbody>
<tr>
<td valign="top" align="left">&#x000C1;cs et al. (<xref ref-type="bibr" rid="B2">2020</xref>) <break/> Hungary</td>
<td valign="top" align="left">Cross-sectional study <break/> April-end of May <break/> Q</td>
<td valign="top" align="left"><italic>N</italic> = 827 students of 10 faculties at the University of P&#x000E9;cs (25.3 &#x000B1; 8.1 years old) <break/> &#x02642; = 182 <break/> &#x02640; = 645</td>
<td valign="top" align="left">IPAQ</td>
<td valign="top" align="left">National state of emergency. Universities were ordered to suspend in-person classes and switch to online eLearning courses</td>
<td valign="top" align="left">Walking, <italic>min/week</italic>: 342.6 &#x000B1; 303.5 <break/> Moderate, <italic>min/week</italic>: 126.7 &#x000B1; 213.7 <break/> Vigorous, <italic>min/week</italic>: 142.9 &#x000B1; 195.7 <break/> Total PA, <italic>min/week</italic>: 609.8 &#x000B1; 499.2</td>
<td valign="top" align="left">Walking, <italic>min/week</italic>: 162.5 &#x000B1; 237.8 (&#x02193;52.6%) [<italic>p</italic> &#x0003C; 0.001] <break/> Moderate, <italic>min/week</italic>: 136.7 &#x000B1; 220.6 (&#x02191;7.9%) [<italic>p</italic> = 0.170] <break/> Vigorous, <italic>min/week</italic>: 138.7 &#x000B1; 180.5 (&#x02193;2.9%) [<italic>p</italic> = 0.484] <break/> Total PA, <italic>min/week</italic>: 435.4 &#x000B1; 472.0 (&#x02193;28.6%) [<italic>p</italic> &#x0003C; 0.001]</td>
<td valign="top" align="left">Pre-lockdown: vigorous PA was higher among &#x02642; than &#x02640; (<italic>p</italic> = 0.047) <break/> No significant difference was found between genders in comparing total values of PA before and during COVID-19 (<italic>p</italic> = 0.532, <italic>p</italic> = 0.700, respectively)</td>
</tr>
<tr>
<td valign="top" align="left"><break/> Alarc&#x000F3;n Meza and Hall-L&#x000F3;pez (<xref ref-type="bibr" rid="B3">2021</xref>) <break/> Mexico</td>
<td valign="top" align="left">Cross-sectional study <break/> DNS <break/> Q</td>
<td valign="top" align="left"><italic>N</italic> = 32 students of the Faculty of Sports of the Autonomous University of Baja California (21.4 &#x000B1; 3.6 years old) <break/> &#x02642; = 17 <break/> &#x02640; = 15</td>
<td valign="top" align="left">IPAQ</td>
<td valign="top" align="left">&#x02013;</td>
<td valign="top" align="left">Low, <italic>% of participants</italic>: 3.6% <break/> Moderate, <italic>% of participants</italic>: 5.2% <break/> High, <italic>% of participants</italic>: 91.2 <break/> Weekly energy expenditure of PA, <italic>MET-min/week</italic>: 6,473</td>
<td valign="top" align="left">Low, <italic>% of participants</italic>: 10.9 (&#x02191;7.3%) <break/> Moderate, <italic>% of participants</italic>: 6.8 (&#x02191;1.6%) <break/> High, <italic>% of participants</italic>: 82.3 (&#x02193;8.9%) <break/> Weekly energy expenditure PA, <italic>MET- min/week</italic>: 4,297 (&#x02193;33.6%) [<italic>p</italic> = 0.005]</td>
<td/>
</tr>
<tr>
<td valign="top" align="left">Barkley et al. (<xref ref-type="bibr" rid="B10">2020</xref>) <break/> USA</td>
<td valign="top" align="left">Cross-sectional study <break/> May 18&#x02013;June 3 <break/> Q</td>
<td valign="top" align="left"><italic>N</italic> = 100 undergraduate students (26.9 &#x000B1; 8.9 years old)</td>
<td valign="top" align="left">GSLTPAQ<xref ref-type="table-fn" rid="TN1"><sup>a</sup></xref></td>
<td valign="top" align="left">20 March, the campus (including all fitness facilities) was closed soon thereafter and all students were sent home <break/> 22 March, the university&#x00027;s home state issued a &#x0201C;stay at home&#x0201D; order</td>
<td valign="top" align="left">Mild, <italic>Godin score</italic>: 16.3 &#x000B1; 22.6 <break/> Moderate, <italic>Godin score</italic>: 15.0 &#x000B1; 15.7 <break/> Vigorous, <italic>Godin score</italic>: 16.0 &#x000B1; 22.1 <break/> Total PA, <italic>Godin score</italic>: 47.2 &#x000B1; 40.2</td>
<td valign="top" align="left">Mild, <italic>Godin score</italic>: 10.8 &#x000B1; 12.9 (&#x02193;32.5%) [<italic>p</italic> = 0.015] <break/> Moderate, <italic>Godin score</italic>: 12.9 &#x000B1; 12.4 (&#x02193;14%) <break/> Vigorous, <italic>Godin score</italic>: 14.0 &#x000B1; 17.9 (&#x02193;12.5%) <break/> Total PA, <italic>Godin score</italic>: 37.7 &#x000B1; 30.7 (&#x02193;20.1%)</td>
<td/>
</tr>
<tr>
<td valign="top" align="left">Gall&#x000E8; et al. (<xref ref-type="bibr" rid="B25">2020</xref>) <break/> Italy</td>
<td valign="top" align="left">Cross-sectional study <break/> Last three weeks of May <break/> Q</td>
<td valign="top" align="left"><italic>N</italic> = 1,430 students from three Italian universities (22.9 &#x000B1; 3.5 years old) <break/> &#x02642; = 494 <break/> &#x02640; = 936</td>
<td valign="top" align="left">IPAQ</td>
<td valign="top" align="left">Localized and national lockdown. Grocery shopping and walking pets were the only activities allowed</td>
<td valign="top" align="left">Walking, <italic>min/week</italic>: 480 <break/> Moderate, <italic>min/week</italic>: 199.3 <break/> Vigorous, <italic>min/week</italic>: 138.6 <break/> Total PA, <italic>min/week</italic>: 520 &#x000B1; 820</td>
<td valign="top" align="left">Walking, <italic>min/week</italic>: 114.5 (&#x02193;365.5%) [<italic>p</italic> &#x0003C; 0.05] <break/> Moderate, <italic>min/week</italic>: 148.1 (&#x02193;51.2%) [<italic>p</italic> &#x0003C; 0.05] Vigorous, <italic>min/week</italic>: 108.3 (&#x02193;30.3%) [<italic>p</italic> &#x0003C; 0.05] Total PA, <italic>min/week</italic>: 270 &#x000B1; 340 (&#x02193;50%) [<italic>p</italic> &#x0003C; 0.0001]</td>
<td valign="top" align="left">During lockdown: 639 participants (44.7%) remained sufficiently active. Being younger than 22 years old, female, and previously active, attending the universities of Naples and Rome, and having at least one graduate parent were associated with the achievement of recommended levels of PA</td>
</tr>
<tr>
<td valign="top" align="left">Gallo et al. (<xref ref-type="bibr" rid="B26">2020</xref>) <break/> Australia</td>
<td valign="top" align="left">Longitudinal study <break/> Pre: March 19&#x02013;21 2018 (T<sub>1</sub>), March 25&#x02013;27 2019 (T<sub>2</sub>), and March 29-April 3 2020 (T<sub>3</sub>) <break/> During: May 12&#x02013;26 (T<sub>4</sub>) <break/> Q</td>
<td valign="top" align="left"><italic>N</italic> = 509 students from the University of Queensland (22.5 &#x000B1; 0.08 years old) <break/> &#x02642; = 214 <break/> &#x02640; = 295</td>
<td valign="top" align="left">The Active Australia Survey</td>
<td valign="top" align="left">Localized lockdown <break/> 23 March, all but essential services were shut down and universities transitioned all undergraduate learning online <break/> 30 March, people were only allowed to leave their homes for work (in an essential service), or to purchase food, receive or provide medical care, or exercise</td>
<td valign="top" align="left">&#x02642; Walking, <italic>min/week</italic> (median &#x000B1; IQR): <break/> T<sub>1</sub>: &#x0007E;150 &#x000B1;&#x0007E;100; &#x0007E;250 <break/> T<sub>2</sub>: &#x0007E;130 &#x000B1;&#x0007E;100; &#x0007E;220 <break/> &#x02642; Vigorous, <italic>min/week</italic> (median &#x000B1; IQR): <break/> T<sub>1</sub>: &#x0007E;245 &#x000B1;&#x0007E;110; &#x0007E;400 <break/> T<sub>2</sub>: &#x0007E;135 &#x000B1;&#x0007E;100; &#x0007E;300 <break/> &#x02640; Walking, <italic>min/week</italic> (median &#x000B1; IQR): <break/> T<sub>1</sub>: &#x0007E;125 &#x000B1;&#x0007E;100; &#x0007E;90 <break/> T<sub>2</sub>: &#x0007E;125 &#x000B1;&#x0007E;100; &#x0007E;200 <break/> &#x02640; Vigorous, <italic>min/week</italic> (median &#x000B1; IQR): <break/> T<sub>1</sub>: &#x0007E;120 &#x000B1;&#x0007E;60; &#x0007E;220 <break/> T<sub>2</sub>: &#x0007E;120 &#x000B1;&#x0007E;55; &#x0007E;215</td>
<td valign="top" align="left">&#x02642; Walking, <italic>min/week</italic> (median &#x000B1; IQR): <break/> T<sub>3</sub>: &#x0007E;75 &#x000B1;&#x0007E;60; &#x0007E;145 (T<sub>1</sub>: &#x02193;50%; T<sub>2</sub>: &#x02193;42.3%) [<italic>p</italic> &#x0003C; 0.0001 between T<sub>3</sub> and T<sub>1</sub>] <break/> &#x02642; Vigorous, <italic>min/week</italic> (median &#x000B1; IQR): <break/> T<sub>3</sub>: 100 &#x000B1;&#x0007E;70; &#x0007E;220 (T<sub>1</sub>: &#x02193;59.2%; T<sub>2</sub>: &#x02193;25.9%) [<italic>p</italic> &#x0003C; 0.0001 between T<sub>3</sub> and T<sub>1</sub>] <break/> &#x02640; Walking, <italic>min/week</italic> (median &#x000B1; IQR): <break/> T<sub>3</sub>: &#x0007E;100 &#x000B1; &#x0007E;50; &#x0007E;185 (T<sub>1</sub>: &#x02193;20%; T<sub>2</sub>: &#x02193;20%) [<italic>p</italic> &#x0003C; 0.05 between T<sub>3</sub> and T<sub>2</sub>] <break/> &#x02640; Vigorous, <italic>min/week</italic> (median &#x000B1; IQR): <break/> T<sub>3</sub>: &#x0007E;90 &#x000B1; &#x0007E;55; &#x0007E;145 (T<sub>1</sub>: &#x02193;25%; T<sub>2</sub>: &#x02193;25%)</td>
<td valign="top" align="left">&#x02642; Time spent walking: <break/> T<sub>3</sub> &#x0003C; T<sub>2</sub> (&#x02193;52.5 min) [<italic>p</italic> &#x0003C; 0.05] <break/> T<sub>3</sub> &#x0003C; T<sub>1</sub> (&#x02193;87.5 min) [<italic>p</italic> &#x0003C; 0.0001] <break/> &#x02642; Time spent in vigorous activity [<italic>p</italic> &#x0003C; 0.0001]: <break/> T<sub>3</sub> &#x0003C; T<sub>2</sub> (&#x02193;60 min) [<italic>p</italic> &#x0003C; 0.05] <break/> T<sub>3</sub> &#x0003C; T<sub>1</sub> (&#x02193;150 min) [<italic>p</italic> &#x0003C; 0.0001] <break/> &#x02640; Time spent walking: <break/> T<sub>3</sub> &#x0003C; T<sub>2</sub> (&#x02193;30 min) [<italic>p</italic> &#x0003C; 0.05] <break/> T<sub>3</sub> &#x0003C; T<sub>1</sub> (&#x02193;30 min) [<italic>p</italic> &#x0003C; 0.068] <break/> &#x02642; No differences in time spent in vigorous activity between the time points of the study <break/> PA levels T<sub>4</sub> vs. T<sub>3</sub>: No change for the majority of &#x02642; <break/> PA levels T<sub>4</sub> vs. T<sub>3</sub>: increased for &#x0003E;40% of &#x02640;</td>
</tr>
<tr>
<td valign="top" align="left">Karuc et al. (<xref ref-type="bibr" rid="B34">2020</xref>) <break/> Croatia</td>
<td valign="top" align="left">Longitudinal survey design <break/> April 24&#x02013;May 8 <break/> Q</td>
<td valign="top" align="left"><italic>N</italic> = 91 university students <break/> &#x02642; = 32 (21.5 &#x000B1; 0.3 years old) <break/> &#x02640; = 59 (21.6 &#x000B1; 0.4 years old)</td>
<td valign="top" align="left">SHAPES</td>
<td valign="top" align="left">National lockdown. Government measures to restrict gathering in public places and parks, suspend public transportation, and close institutions. All social gatherings, work in retail and services including sports activities were prohibited</td>
<td valign="top" align="left">&#x02642; MVPA, <italic>min/day</italic> (median &#x000B1; IQR): 135 &#x000B1; 127.5 <break/> &#x02640; MVPA, <italic>min/day</italic> (median &#x000B1; IQR): 120 &#x000B1; 227.1</td>
<td valign="top" align="left">&#x02642; MVPA, <italic>min/day</italic> (median &#x000B1; IQR): 85.7 &#x000B1; 56.8 (&#x02193;36.5%; &#x02193;57.7 <italic>min/day</italic> [<italic>p</italic> = 0.006]) <break/> &#x02640; MVPA, <italic>min/day</italic> (median &#x000B1; IQR): 64.3 &#x000B1; 75.0 (&#x02193;46.4%; 64.8 <italic>min/day</italic> [<italic>p</italic> &#x0003C; 0.0001])</td>
<td valign="top" align="left">&#x02642; Same PA levels: 31% <break/> &#x02642; Increased PA levels: 19% <break/> &#x02642; Decreased PA levels: 50% <break/> &#x02640; Same PA levels: 25% <break/> &#x02640; Increased PA levels: 19% <break/> &#x02640; Decreased PA levels: 56%</td>
</tr>
<tr>
<td valign="top" align="left">Maher et al. (<xref ref-type="bibr" rid="B40">2020</xref>) <break/> USA</td>
<td valign="top" align="left">Cross-sectional study <break/> Pre: January 21&#x02013;March 11 <break/> During: April 17&#x02013;May 5 <break/> Q</td>
<td valign="top" align="left"><italic>N</italic> = 107 undergraduate kinesiology students (21.7 &#x000B1; 2.6 years old)</td>
<td valign="top" align="left">IPAQ-SF</td>
<td valign="top" align="left">March 13, campus closure <break/> March 25, executive orders banning mass gatherings and closure of non-essential businesses for the state <break/> March 30&#x02013;May 8, mandatory stay-at-home orders for the state</td>
<td valign="top" align="left">MVPA, <italic>min/week</italic>: 424.6 &#x000B1; 372.0</td>
<td valign="top" align="left">MVPA, <italic>min/week</italic>: 324.7 &#x000B1; 316.6 (&#x02193;23.5%) [<italic>p</italic> = 0.02]</td>
<td/>
</tr>
<tr>
<td valign="top" align="left">Romero-Blanco et al. (<xref ref-type="bibr" rid="B46">2020</xref>) <break/> Spain</td>
<td valign="top" align="left">Cross-sectional study <break/> Pre: January 15&#x02013;30 <break/> During: April 1&#x02013;15 <break/> Q</td>
<td valign="top" align="left"><italic>N</italic> = 213 health sciences students (20.5 &#x000B1; 4.5 years old) <break/> &#x02642; = 41 <break/> &#x02640; = 172</td>
<td valign="top" align="left">IPAQ-SF</td>
<td valign="top" align="left">Localized and national lockdown <break/> March-April, prohibition on going outside to engage in sporting or social activities</td>
<td valign="top" align="left">Moderate, <italic>min/week</italic>: 42.8 &#x000B1; 48.4 <break/> Vigorous, <italic>min/week</italic>: 28.5 &#x000B1; 54.1 <break/> Total PA, <italic>min/week</italic>: 223.3 &#x000B1; 305.5 <break/> &#x02642; Total PA, <italic>min/week</italic>: 226.5 &#x000B1; 250.1 min/week <break/> &#x02640; Total PA, <italic>min/week</italic>: 222.5 &#x000B1; 317.9</td>
<td valign="top" align="left">Moderate, <italic>min/week</italic>: 47.7 &#x000B1; 50.8 (&#x02191;4.7%) [<italic>p</italic> = 0.353] <break/> Vigorous, <italic>min/week</italic>: 30.6 &#x000B1; 30.9 (&#x02191;7.4%) [<italic>p</italic> = 0.07] <break/> Total PA, <italic>min/week</italic>: 383.2 &#x000B1; 438.9 (&#x02191;71.6%) [<italic>p</italic> &#x0003C; 0.001] <break/> &#x02642; Total PA, <italic>min/week</italic>: 279.9 &#x000B1; 446.9 (&#x02191;23.6%) [<italic>p</italic> = 0.339] <break/> &#x02640; Total PA, <italic>min/week</italic>: 407.8 &#x000B1; 404.8 (&#x02191;83.3%) [<italic>p</italic> &#x0003C; 0.001]</td>
<td/>
</tr>
<tr>
<td valign="top" align="left">Sa&#x000F1;udo et al. (<xref ref-type="bibr" rid="B47">2020</xref>) <break/> Spain</td>
<td valign="top" align="left">Longitudinal survey design <break/> Pre: one week in February <break/> During: March 24&#x02013;3 April <break/> Q and accelerometer</td>
<td valign="top" align="left"><italic>N</italic> = 20 university students (22.6 &#x000B1; 3.4 years old) <break/> &#x02642; = 11 <break/> &#x02640; = 9</td>
<td valign="top" align="left">IPAQ <break/> Wristband</td>
<td valign="top" align="left">Localized and national lockdownMarch-April, prohibition on going outside to engage in sporting or social activities</td>
<td valign="top" align="left">Walking, <italic>min/week</italic>: 362 &#x000B1; 262 <break/> Moderate, <italic>min/week</italic>: 441 &#x000B1; 487 <break/> Moderate-to-vigorous, <italic>min/week</italic>: 797 &#x000B1; 822 <break/> Vigorous, <italic>min/week</italic>: 356 &#x000B1; 381 min/week <break/> Objectively measured PA, <italic>steps/day</italic>: 8,525 &#x000B1; 3,597</td>
<td valign="top" align="left">Walking, <italic>min/week</italic>: 27 &#x000B1; 47 (&#x02193;92.5%) [<italic>p</italic> &#x0003C; 0.0001] <break/> Moderate, <italic>min/week</italic>: 178 &#x000B1; 155 (&#x02193;59.7%) [<italic>p</italic> = 0.028] <break/> Moderate-to-vigorous PA, <italic>min/week</italic>: 346 &#x000B1; 341 (&#x02193;56.6%) [0.005] <break/> Vigorous, <italic>min/week</italic>: 168 &#x000B1; 228 (&#x02193;52.8%) [<italic>p</italic> = 0.006] <break/> Objectively measured PA, <italic>steps/day</italic>: 2,754 &#x000B1; 1,724 (&#x02193;67.7%) [<italic>p</italic> &#x0003C; 0.0001]</td>
<td valign="top" align="left">Participants meeting the PA guidelines (WHO): 84% at pre-lockdown, 74% during lockdown</td>
</tr>
<tr>
<td valign="top" align="left">Savage et al. (<xref ref-type="bibr" rid="B48">2020</xref>) <break/> England</td>
<td valign="top" align="left">Longitudinal cohort study <break/> Pre: October 14&#x02013;20 2019 (T<sub>1</sub>), January 28-February 3 2020 (T<sub>2</sub>) <break/> During: March 20&#x02013;26 March (T<sub>3</sub>, 1st week of lockdown), 27 April 27-May 3 (T<sub>4</sub>, 5th week of lockdown) <break/> Q</td>
<td valign="top" align="left"><italic>N</italic> = 214 students from East Midlands university (20 years old) <break/> &#x02642; = 60 <break/> &#x02640; = 154</td>
<td valign="top" align="left">EVS</td>
<td valign="top" align="left">People in the United Kingdom were required to stay at home as much as possible and were only allowed to leave once per day for exercise</td>
<td valign="top" align="left">&#x02642; MVPA, <italic>min/week</italic>: <break/> T<sub>1:</sub> 296 &#x000B1; 254 <break/> &#x02640; MVPA, <italic>min/week</italic>: <break/> T<sub>1</sub>: 231 &#x000B1; 232</td>
<td valign="top" align="left">&#x02642; MVPA, <italic>min/week</italic>: <break/> T<sub>4</sub>: 220 &#x000B1; 252 (&#x02193;25.7%) <break/> &#x02640; MVPA, <italic>min/</italic>week: <break/> T<sub>4</sub>: 222 &#x000B1; 208 (&#x02193;3.9%)</td>
<td valign="top" align="left">At all-time points: average MVPA &#x0003E;150 min/week <break/> During T<sub>3</sub>-T<sub>4</sub>: &#x02193;28 min/week of moderate to vigorous PA (on average) <break/> The reduction in PA was more pronounced in &#x02642; than &#x02640;</td>
</tr>
</tbody>
</table>
<table-wrap-foot>
<p><italic>&#x02013;, Not information available; min, minutes; DNS, date note specified; EVS, Exercise Vital Sign questionnaire; GSLTPAQ, Godin-Shephard Leisure-Time Physical Activity Questionnaire; IPAQ, International Physical Activity Questionnaire; IPAQ-SF, International Physical Activity Questionnaire-Short Form; SHAPES, School Health Action, Planning, and Evaluation System questionnaire; MET, metabolic equivalent; MVPA, moderate-vigorous physical activity; PA, physical activity; Q, questionnaire/survey</italic>.</p>
<fn id="TN1"><label>a</label><p><italic>A score for each intensity is calculate using the following equations: times per week participating in strenuous &#x000D7; 9, moderate &#x000D7; 5, mild &#x000D7; 3. Each of these individual scores was then summed for a total physical activity score. &#x02640;, female; &#x02642;, male; &#x02191;, increase; &#x02193;, decrease/decline</italic>.</p></fn>
</table-wrap-foot>
</table-wrap>
<p>Six out of ten studies used International Physical Activity Questionnaire (IPAQ) as tool to assess the level of PA performed by university students, while the Godin physical activity questionnaire, the Active Australia Survey, the School Health Action, Planning, and Evaluation System (SHAPES) questionnaire and Exercise vital sign (EVS) questionnaire were used in the rest of studies. Only one study (Sa&#x000F1;udo et al., <xref ref-type="bibr" rid="B47">2020</xref>) used an objective tool to assess PA (accelerometer). Regarding the level of the lockdown by country, most of the studies (Alarc&#x000F3;n-Meza&#x00027;s study did not indicate the country&#x00027;s measures regarding PA during lockdown), reflected that national lockdown included a restriction for outdoor PA.</p>
<p>With regards to the reporting risk of bias of the studies, NOS scale showed that six studies had low risk of bias, while four studies got 6 stars, so they show a high risk of bias. The quality of evidence according to GRADE was downgraded to low (risk of bias, and indirectness). The detailed data for NOS and GRADE scales are presented in <xref ref-type="table" rid="T2">Tables 2</xref>, <xref ref-type="table" rid="T3">3</xref>, respectively.</p>
<table-wrap position="float" id="T2">
<label>Table 2</label>
<caption><p>Risk of bias assessment of the studies (Newcastle-Ottawa scale).</p></caption>
<table frame="hsides" rules="groups">
<thead><tr>
<th valign="top" align="left"><bold>Study</bold></th>
<th valign="top" align="center" colspan="9" style="border-bottom: thin solid #000000;"><bold>Criteria for assessing risk of bias</bold></th>
</tr>
<tr>
<th/>
<th valign="top" align="center"><bold>1</bold></th>
<th valign="top" align="center"><bold>2</bold></th>
<th valign="top" align="center"><bold>3</bold></th>
<th valign="top" align="center"><bold>4</bold></th>
<th valign="top" align="center"><bold>5</bold></th>
<th valign="top" align="center"><bold>6</bold></th>
<th valign="top" align="center"><bold>7</bold></th>
<th valign="top" align="center"><bold>8</bold></th>
<th valign="top" align="center"><bold>Total</bold></th>
</tr>
</thead>
<tbody>
<tr>
<td valign="top" align="left">&#x000C1;cs et al. (<xref ref-type="bibr" rid="B2">2020</xref>)</td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td/>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td/>
<td valign="top" align="center">6</td>
</tr>
<tr>
<td valign="top" align="left">Alarc&#x000F3;n Meza and Hall-L&#x000F3;pez (<xref ref-type="bibr" rid="B3">2021</xref>)</td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td/>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td/>
<td valign="top" align="center">7</td>
</tr>
<tr>
<td valign="top" align="left">Barkley et al. (<xref ref-type="bibr" rid="B10">2020</xref>)</td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td/>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td/>
<td valign="top" align="center">6</td>
</tr>
<tr>
<td valign="top" align="left">Gall&#x000E8; et al. (<xref ref-type="bibr" rid="B25">2020</xref>)</td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td/>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td/>
<td valign="top" align="center">6</td>
</tr>
<tr>
<td valign="top" align="left">Gallo et al. (<xref ref-type="bibr" rid="B26">2020</xref>)</td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td/>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center">7</td>
</tr>
<tr>
<td valign="top" align="left">Karuc et al. (<xref ref-type="bibr" rid="B34">2020</xref>)</td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td/>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td/>
<td valign="top" align="center">6</td>
</tr>
<tr>
<td valign="top" align="left">Maher et al. (<xref ref-type="bibr" rid="B40">2020</xref>)</td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td/>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center">7</td>
</tr>
<tr>
<td valign="top" align="left">Romero-Blanco et al. (<xref ref-type="bibr" rid="B46">2020</xref>)</td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td/>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center">7</td>
</tr>
<tr>
<td valign="top" align="left">Sa&#x000F1;udo et al. (<xref ref-type="bibr" rid="B47">2020</xref>)</td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td/>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center">8</td>
</tr>
<tr>
<td valign="top" align="left">Savage et al. (<xref ref-type="bibr" rid="B48">2020</xref>)</td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td/>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center"><xref ref-type="table-fn" rid="TN2"><sup>&#x0002A;</sup></xref></td>
<td valign="top" align="center">7</td>
</tr>
</tbody>
</table>
<table-wrap-foot>
<p><italic>Criteria for assessing risk of bias: (1) representativeness of the exposed cohort; (2) selection of the non-exposed cohort; (3) ascertainment of exposure; (4) demonstration that outcome of interest was not present at start of study; (5) comparability of cohorts on the basis of the design or analysis (A maximum of two stars can be allotted in this category); (6) assessment. of outcome; (7) was follow-up long enough for outcomes to occur; (8) adequacy of follow-up of cohorts</italic>.</p>
<fn id="TN2"><label>&#x0002A;</label><p><italic>Star(s) awarded for each criterion</italic>.</p></fn>
</table-wrap-foot>
</table-wrap>
<table-wrap position="float" id="T3">
<label>Table 3</label>
<caption><p>Summary of findings (GRADE).</p></caption>
<table frame="hsides" rules="groups">
<thead><tr>
<th valign="top" align="left"><bold>N<bold>&#x000B0;</bold> of studies</bold></th>
<th valign="top" align="center" colspan="6" style="border-bottom: thin solid #000000;"><bold>Certainty assessment</bold></th>
<th valign="top" align="center"><bold>Certainty</bold></th>
</tr>
<tr>
<th/>
<th valign="top" align="left"><bold>Study design</bold></th>
<th valign="top" align="left"><bold>Risk of bias</bold></th>
<th valign="top" align="left"><bold>Inconsistency</bold></th>
<th valign="top" align="left"><bold>Indirectness</bold></th>
<th valign="top" align="left"><bold>Imprecision</bold></th>
<th valign="top" align="left"><bold>Other considerations</bold></th>
<th/>
</tr>
</thead>
<tbody>
<tr>
<td valign="top" align="left" colspan="8"><bold>Physical activity level pre-during COVID lockdown</bold></td>
</tr>
<tr>
<td valign="top" align="left">10</td>
<td valign="top" align="left">Observational studies</td>
<td valign="top" align="left">Serious<xref ref-type="table-fn" rid="TN3"><sup>a</sup></xref></td>
<td valign="top" align="left">Not serious</td>
<td valign="top" align="left">Serious<xref ref-type="table-fn" rid="TN4"><sup>b</sup></xref></td>
<td valign="top" align="left">Not serious</td>
<td valign="top" align="left">Very strong association</td>
<td valign="top" align="center">&#x02295;&#x02295;&#x025EF;&#x025EF; LOW</td>
</tr>
</tbody>
</table>
<table-wrap-foot>
<fn id="TN3"><label>a</label><p><italic>Four studies reported high risk of bias (assessed with the Newcastle Ottawa Scale)</italic>.</p></fn>
<fn id="TN4"><label>b</label><p><italic>The information provided by two studies does not answer completely the main question about levels of physical activity. These circles represent the degree of certainty of the variable analysed on the GRADE scale. A circle with a &#x0201C;&#x0002B;&#x0201D; symbol inside represents a very low certainty of this variable, two circles with the &#x0201C;&#x0002B;&#x0201D; symbol inside represent low certainty, three circles with the &#x0201C;&#x0002B;&#x0201D; symbol indicate moderate certainty and the four circles with the symbol &#x0201C;&#x0002B;&#x0201D; represent a high certainty of this variable</italic>.</p></fn>
</table-wrap-foot>
</table-wrap>
</sec>
<sec>
<title>Physical Activity Levels</title>
<p>Nine out of the ten studies included in the systematic review showed significant decreases in PA levels during lockdown, both in questionnaires as accelerometers. Surprisingly, one study (Romero-Blanco et al., <xref ref-type="bibr" rid="B46">2020</xref>) showed significant increases in PA levels among university students during lockdown. Romero-Blanco et al. (<xref ref-type="bibr" rid="B46">2020</xref>) showed that Health Sciences university students performed significantly higher minutes/week of total PA (&#x0002B;71.6%) and vigorous PA (&#x0002B;7.4%), both males (&#x0002B; 83.3%) as females (&#x0002B; 23.6%). On the other hand, Sa&#x000F1;udo et al. (<xref ref-type="bibr" rid="B47">2020</xref>) showed an objective reduction in PA with 67.7% fewer steps per day during the lockdown. In the same line, five studies showed a reduction of light/mild PA (walking) between 32.5 and 365.5% compared to the period prior to confinement (&#x000C1;cs et al., <xref ref-type="bibr" rid="B2">2020</xref>; Barkley et al., <xref ref-type="bibr" rid="B10">2020</xref>; Gall&#x000E8; et al., <xref ref-type="bibr" rid="B25">2020</xref>; Gallo et al., <xref ref-type="bibr" rid="B26">2020</xref>; Sa&#x000F1;udo et al., <xref ref-type="bibr" rid="B47">2020</xref>), three studies found a decrease in moderate PA levels (from 14&#x02013;59.7%) (Barkley et al., <xref ref-type="bibr" rid="B10">2020</xref>; Gall&#x000E8; et al., <xref ref-type="bibr" rid="B25">2020</xref>; Sa&#x000F1;udo et al., <xref ref-type="bibr" rid="B47">2020</xref>) and four studies in moderate-to-vigorous PA (MVPA) (from 3.9&#x02013;56.6%) (Karuc et al., <xref ref-type="bibr" rid="B34">2020</xref>; Maher et al., <xref ref-type="bibr" rid="B40">2020</xref>; Sa&#x000F1;udo et al., <xref ref-type="bibr" rid="B47">2020</xref>; Savage et al., <xref ref-type="bibr" rid="B48">2020</xref>). Finally, seven studies also revealed a reduction of high/vigorous PA between 2.9 and 52.8% compared to pre-lockdown (&#x000C1;cs et al., <xref ref-type="bibr" rid="B2">2020</xref>; Barkley et al., <xref ref-type="bibr" rid="B10">2020</xref>; Gall&#x000E8; et al., <xref ref-type="bibr" rid="B25">2020</xref>; Gallo et al., <xref ref-type="bibr" rid="B26">2020</xref>; Romero-Blanco et al., <xref ref-type="bibr" rid="B46">2020</xref>; Sa&#x000F1;udo et al., <xref ref-type="bibr" rid="B47">2020</xref>; Alarc&#x000F3;n Meza and Hall-L&#x000F3;pez, <xref ref-type="bibr" rid="B3">2021</xref>) and two studies showed a decrease of total PA (28.6 and 50%) (&#x000C1;cs et al., <xref ref-type="bibr" rid="B2">2020</xref>; Gall&#x000E8; et al., <xref ref-type="bibr" rid="B25">2020</xref>). Regarding gender differences, two studies found a higher reduction of walking, vigorous and MVPA in males (Gallo et al., <xref ref-type="bibr" rid="B26">2020</xref>; Savage et al., <xref ref-type="bibr" rid="B48">2020</xref>), while only one study showed a higher reduction in females (Karuc et al., <xref ref-type="bibr" rid="B34">2020</xref>). Otherwise, Romero-Blanco et al. (<xref ref-type="bibr" rid="B46">2020</xref>) found that women had performed more PA (min/week) than male during lockdown. The main results of the studies included in this systematic review are presented in <xref ref-type="table" rid="T1">Table 1</xref>. According to the reported data, those students who met the PA recommendations before the confinement took place, were still classified as physically active during the lockdown period.</p>
</sec>
</sec>
<sec sec-type="discussion" id="s4">
<title>Discussion</title>
<p>This review aimed to analyze if PA levels of university students changed during the confinements in different countries. Our results are of interest from a public health perspective to the purpose of addressing the impact of the confinements on health-related habits such as PA and how we could help to reduce it and its derived problems.</p>
<p>We found that total of nine out of the ten included studies reported significant decreases in PA levels during the confinements. These results are in line with the findings from previous studies in both adults and children. Casta&#x000F1;eda-Babarro et al. (<xref ref-type="bibr" rid="B18">2020</xref>) reported significant decreases in self-reported vigorous PA and walking time of 16.8 and 58.2%, respectively; whereas time spent in sedentary behavior increased during the confinement in Spain. The student group (from children to university students) showed the highest decrease in moderate, vigorous, and waking activities. In the mini-review from Arora and Grey (<xref ref-type="bibr" rid="B7">2020</xref>) the authors reported that increased social isolation is associated with higher rates of physical inactivity and sedentarism in adults. Dunton et al. (<xref ref-type="bibr" rid="B24">2020</xref>) reported that the COVID-19 pandemic has also negatively affected the PA levels of children living in the United States.</p>
<p>University students generally reduce its PA levels compared to their childhood. Factors affecting the decline of PA levels during this life stage include changes in psychosocial aspects and residency (i.e. distance to the university; Van Dyck et al., <xref ref-type="bibr" rid="B50">2015</xref>) and greater time demands, such as work and class time (Calestine et al., <xref ref-type="bibr" rid="B17">2017</xref>). Our findings expand this previous knowledge by suggesting that the reduction in total PA levels has been exacerbated during the confinements.</p>
<p>This finding is important for two main aspects. First, because it has been reported that the confinements developed to fight COVID-19 have increased mental health problems in both adults (Guo et al., <xref ref-type="bibr" rid="B27">2020</xref>; Holingue et al., <xref ref-type="bibr" rid="B31">2020</xref>; van Tilburg et al., <xref ref-type="bibr" rid="B51">2020</xref>) and young populations (Arora and Grey, <xref ref-type="bibr" rid="B7">2020</xref>; Jiao et al., <xref ref-type="bibr" rid="B32">2020</xref>; Savage et al., <xref ref-type="bibr" rid="B48">2020</xref>). Our results confirm that PA levels were generally reduced during the lockdowns compared to the previous situation. Efforts should be made to increase PA levels in this situation not only for the sake of physical health but also psychological well-being. Furthermore, incentivizing a routine through daily at-home PA could help maintaining a certain sense of routine and organization, helping to maintain mental health during the lockdown and also facilitate the routine back to university (Burtscher et al., <xref ref-type="bibr" rid="B16">2020</xref>). Second, because it is well-known that sedentary behavior and insufficient PA patterns in childhood are likely to persist into adulthood, increasing the risk of major health complications (i.e. being overweight or obese, type II diabetes or hypertension; 2018 Physical Activity Guidelines Advisory Committee, <xref ref-type="bibr" rid="B1">2018</xref>) and university students are transitioning within these two life stages.</p>
<p>Another interesting finding from our review is that, generally, those that were sufficiently active before the confinement (i.e., achieving current minimum recommendations for adults of at least 150 min per week of MVPA; U.S. Department of Health Human Services, <xref ref-type="bibr" rid="B49">2018</xref>), were also sufficiently active during the lockdown, despite the reduction in PA levels. This finding, which has been reported also in adults (Casta&#x000F1;eda-Babarro et al., <xref ref-type="bibr" rid="B18">2020</xref>), could suggest that achieving the recommendations on MVPA help in creating a stronger habit of being physically active, which seemed not to be affected to a large extent by the confinements imposed due to COVID-19.</p>
<p>Our study has some strengths and limitations than need to be considered. First, while we included more than 3.500 university students from eight different countries, the pandemic affected differently each country and the level of restrictions may not be generalizable to other countries that were not represented in our review. Second, while we had some studies using direct measurements of PA, data were mostly collected from self-report, which is susceptible to cognitive bias. Third, we included six studies with low risk of bias following our methodological quality assessment, but the other 4 were considered to present high risk of bias. Fourth, a meta-analysis was not performed due to the heterogeneity of measurement tools, analyses and populations in the included studies, as well as in their methodological quality. Fifth, the heterogeneity in the analyses carried out in these studies did not allow to draw firm conclusions on how PA levels were differently affected for men and women. Finally, we included people from generally high-income countries.</p>
<p>Taken together, our findings suggest a decrease in PA levels from before to during the COVID-19 outbreak in university students of Australia, Croatia, England, Hungary, Italy, Mexico, Spain, and USA. In times of pandemic crisis, government and university leaders across these countries need to implement measures and advice to encourage this population to increase and maintain adequate levels of PA, as recently suggested by the WHO (Bull et al., <xref ref-type="bibr" rid="B15">2020</xref>). In this context, a set of practical recommendations on how to be active outdoors and indoors during the current and ongoing COVID-19 pandemic can be applied to university students (Bentlage et al., <xref ref-type="bibr" rid="B12">2020</xref>; Ammar et al., <xref ref-type="bibr" rid="B6">2021</xref>). Physical activity programs, individually tailored to the participant&#x00027;s fitness level, should be developed. These programs could be delivered through gamification, communication and interactive coaching technologies (Ammar et al., <xref ref-type="bibr" rid="B6">2021</xref>). For instance, group-based interventions using active videogames seem to be a motivating, enjoyable easy-to-use strategy for reducing social isolation among younger age groups (Viana and de Lira, <xref ref-type="bibr" rid="B52">2020</xref>). This is of particular concern given the experience of loneliness tends to be most common in young adults (Beam and Kim, <xref ref-type="bibr" rid="B11">2020</xref>). However, professional physical guidance, especially in the context of online PA sessions, is needed for university students (Deng et al., <xref ref-type="bibr" rid="B21">2020</xref>). Hence, the work of exercise professionals would be essential to ensure that PA programs are properly designed, monitored and implemented, which is of most importance to guarantee safety and efficacy of exercise training and long-term PA adherence (Natalucci et al., <xref ref-type="bibr" rid="B43">2020</xref>).</p>
</sec>
<sec sec-type="conclusions" id="s5">
<title>Conclusion</title>
<p>Walking, moderate, vigorous, and total PA levels have been reduced during the COVID-19 pandemic confinements in university students of different countries. Despite of the reductions, those who met the current minimum PA recommendations before, generally met the recommendations also during the confinements.</p>
</sec>
<sec sec-type="data-availability-statement" id="s6">
<title>Data Availability Statement</title>
<p>The original contributions generated for the study are included in the article/<xref ref-type="supplementary-material" rid="SM1">Supplementary Material</xref>, further inquiries can be directed to the corresponding author/s.</p>
</sec>
<sec id="s7">
<title>Author Contributions</title>
<p>DS-I and CA contributed in the conception and design of the study. AL-V and DS-I took part in the acquisition and analysis of data. AL-V, MAS-L, and CA contributed drafting the article. DS-I, AL-V, and CA approved the last version to be published. All authors were involved in interpretation of the data. All authors critically revised the article for important intellectual content.</p>
</sec>
<sec sec-type="COI-statement" id="conf1">
<title>Conflict of Interest</title>
<p>The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.</p>
</sec>
</body>
<back>
<sec sec-type="supplementary-material" id="s8">
<title>Supplementary Material</title>
<p>The Supplementary Material for this article can be found online at: <ext-link ext-link-type="uri" xlink:href="https://www.frontiersin.org/articles/10.3389/fpsyg.2020.624567/full#supplementary-material">https://www.frontiersin.org/articles/10.3389/fpsyg.2020.624567/full#supplementary-material</ext-link></p>
<supplementary-material xlink:href="Table_1.DOC" id="SM1" mimetype="application/msword" xmlns:xlink="http://www.w3.org/1999/xlink"/>
<supplementary-material xlink:href="Table_2.DOCX" id="SM2" mimetype="application/vnd.openxmlformats-officedocument.wordprocessingml.document" xmlns:xlink="http://www.w3.org/1999/xlink"/>
</sec>
<ref-list>
<title>References</title>
<ref id="B1">
<citation citation-type="web"><person-group person-group-type="author"><collab>2018 Physical Activity Guidelines Advisory Committee</collab></person-group> (<year>2018</year>). <source>2018 Physical Activity Guidelines Advisory Committee Scientific Report</source>. Available online at: <ext-link ext-link-type="uri" xlink:href="https://health.gov/our-work/physical-activity/current-guidelines/scientific-report">https://health.gov/our-work/physical-activity/current-guidelines/scientific-report</ext-link> (accessed October 24, 2020).</citation></ref>
<ref id="B2">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>&#x000C1;cs</surname> <given-names>P.</given-names></name> <name><surname>Pr&#x000E9;musz</surname> <given-names>V.</given-names></name> <name><surname>Morvay-Sey</surname> <given-names>K.</given-names></name> <name><surname>P&#x000E1;lv&#x000F6;lgyi</surname> <given-names>&#x000C1;.</given-names></name> <name><surname>Trpkovici</surname> <given-names>M.</given-names></name> <name><surname>Elbert</surname> <given-names>G.</given-names></name> <etal/></person-group>. (<year>2020</year>). <article-title>Effects of COVID-19 on physical activity behavior among university students: results of a hungarian online survery</article-title>. <source>Heal. Probl. Civiliz.</source> <volume>14</volume>, <fpage>174</fpage>&#x02013;<lpage>182</lpage>. <pub-id pub-id-type="doi">10.5114/hpc.2020.98472</pub-id></citation></ref>
<ref id="B3">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Alarc&#x000F3;n Meza</surname> <given-names>E. I.</given-names></name> <name><surname>Hall-L&#x000F3;pez</surname> <given-names>J. A.</given-names></name></person-group> (<year>2021</year>). <article-title>Physical activity in university student athletes, prior and in confinement due to pandemic associated with COVID-19</article-title>. <source>Retos</source> <volume>39</volume>, <fpage>572</fpage>&#x02013;<lpage>575</lpage>. <pub-id pub-id-type="doi">10.47197/retos.v0i39.81293</pub-id></citation></ref>
<ref id="B4">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Ammar</surname> <given-names>A.</given-names></name> <name><surname>Brach</surname> <given-names>M.</given-names></name> <name><surname>Trabelsi</surname> <given-names>K.</given-names></name> <name><surname>Chtourou</surname> <given-names>H.</given-names></name> <name><surname>Boukhris</surname> <given-names>O.</given-names></name> <name><surname>Masmoudi</surname> <given-names>L.</given-names></name> <etal/></person-group>. (<year>2020a</year>). <article-title>Effects of COVID-19 home confinement on eating behaviour and physical activity: results of the ECLB-COVID19 international online survey</article-title>. <source>Nutrients</source> <volume>12</volume>:<fpage>1583</fpage>. <pub-id pub-id-type="doi">10.3390/nu12061583</pub-id><pub-id pub-id-type="pmid">32481594</pub-id></citation></ref>
<ref id="B5">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Ammar</surname> <given-names>A.</given-names></name> <name><surname>Chtourou</surname> <given-names>H.</given-names></name> <name><surname>Boukhris</surname> <given-names>O.</given-names></name> <name><surname>Trabelsi</surname> <given-names>K.</given-names></name> <name><surname>Masmoudi</surname> <given-names>L.</given-names></name> <name><surname>Brach</surname> <given-names>M.</given-names></name> <etal/></person-group>. (<year>2020b</year>). <article-title>COVID-19 home confinement negatively impacts social participation and life satisfaction: a worldwide multicenter study</article-title>. <source>Int. J. Environ. Res. Public Health</source> <volume>17</volume>:<fpage>6237</fpage>. <pub-id pub-id-type="doi">10.3390/ijerph17176237</pub-id><pub-id pub-id-type="pmid">32867287</pub-id></citation></ref>
<ref id="B6">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Ammar</surname> <given-names>A.</given-names></name> <name><surname>Trabelsi</surname> <given-names>K.</given-names></name> <name><surname>Brach</surname> <given-names>M.</given-names></name> <name><surname>Chtourou</surname> <given-names>H.</given-names></name> <name><surname>Boukhris</surname> <given-names>O.</given-names></name> <name><surname>Masmoudi</surname> <given-names>L.</given-names></name> <etal/></person-group>. (<year>2021</year>). <article-title>Effects of home confinement on mental health and lifestyle behaviours during the COVID-19 outbreak: insights from the ECLB-COVID19 multicentre study</article-title>. <source>Biol. Sport</source> <volume>38</volume>, <fpage>9</fpage>&#x02013;<lpage>21</lpage>. <pub-id pub-id-type="doi">10.1101/2020.05.04.20091017</pub-id></citation></ref>
<ref id="B7">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Arora</surname> <given-names>T.</given-names></name> <name><surname>Grey</surname> <given-names>I.</given-names></name></person-group> (<year>2020</year>). <article-title>Health behaviour changes during COVID-19 and the potential consequences: a mini-review</article-title>. <source>J. Health Psychol.</source> <volume>25</volume>, <fpage>1155</fpage>&#x02013;<lpage>1163</lpage>. <pub-id pub-id-type="doi">10.1177/1359105320937053</pub-id><pub-id pub-id-type="pmid">32551944</pub-id></citation></ref>
<ref id="B8">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Baker</surname> <given-names>M. G.</given-names></name> <name><surname>Wilson</surname> <given-names>N.</given-names></name> <name><surname>Anglemyer</surname> <given-names>A.</given-names></name></person-group> (<year>2020</year>). <article-title>Successful elimination of covid-19 transmission in New Zealand</article-title>. <source>N. Engl. J. Med.</source> <volume>383</volume>:<fpage>e56</fpage>. <pub-id pub-id-type="doi">10.1056/NEJMc2025203</pub-id><pub-id pub-id-type="pmid">32767891</pub-id></citation></ref>
<ref id="B9">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Balshem</surname> <given-names>H.</given-names></name> <name><surname>Helfand</surname> <given-names>M.</given-names></name> <name><surname>Sch&#x000FC;nemann</surname> <given-names>H. J.</given-names></name> <name><surname>Oxman</surname> <given-names>A. D.</given-names></name> <name><surname>Kunz</surname> <given-names>R.</given-names></name> <name><surname>Brozek</surname> <given-names>J.</given-names></name> <etal/></person-group>. (<year>2011</year>). <article-title>GRADE guidelines: 3</article-title>. <source>Rating the quality of evidence. J. Clin. Epidemiol.</source> <volume>64</volume>, <fpage>401</fpage>&#x02013;<lpage>406</lpage>. <pub-id pub-id-type="doi">10.1016/j.jclinepi.2010.07.015</pub-id><pub-id pub-id-type="pmid">21208779</pub-id></citation></ref>
<ref id="B10">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Barkley</surname> <given-names>J. E.</given-names></name> <name><surname>Lepp</surname> <given-names>A.</given-names></name> <name><surname>Glickman</surname> <given-names>E.</given-names></name> <name><surname>Farnell</surname> <given-names>G. S.</given-names></name> <name><surname>Beiting</surname> <given-names>J.</given-names></name> <name><surname>Wiet</surname> <given-names>R.</given-names></name> <etal/></person-group>. (<year>2020</year>). <article-title>The acute effects of the COVID-19 pandemic on physical activity and sedentary behavior in university students and employees</article-title>. <source>Int. J. Exerc. Sci.</source> <volume>13</volume>, <fpage>1326</fpage>&#x02013;<lpage>1339</lpage>.<pub-id pub-id-type="pmid">33042377</pub-id></citation></ref>
<ref id="B11">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Beam</surname> <given-names>C. R.</given-names></name> <name><surname>Kim</surname> <given-names>A. J.</given-names></name></person-group> (<year>2020</year>). <article-title>Psychological sequelae of social isolation and loneliness might be a larger problem in young adults than older adults</article-title>. <source>Psychol. Trauma Theory Res. Pract. Policy</source> <volume>12</volume>, <fpage>S58</fpage>&#x02013;<lpage>S60</lpage>. <pub-id pub-id-type="doi">10.1037/tra0000774</pub-id><pub-id pub-id-type="pmid">32525372</pub-id></citation></ref>
<ref id="B12">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Bentlage</surname> <given-names>E.</given-names></name> <name><surname>Ammar</surname> <given-names>A.</given-names></name> <name><surname>How</surname> <given-names>D.</given-names></name> <name><surname>Ahmed</surname> <given-names>M.</given-names></name> <name><surname>Trabelsi</surname> <given-names>K.</given-names></name> <name><surname>Chtourou</surname> <given-names>H.</given-names></name> <etal/></person-group>. (<year>2020</year>). <article-title>Practical recommendations for maintaining active lifestyle during the COVID-19 pandemic: a systematic literature review</article-title>. <source>Int. J. Environ. Res. Public Health</source> <volume>17</volume>:<fpage>6265</fpage>. <pub-id pub-id-type="doi">10.3390/ijerph17176265</pub-id><pub-id pub-id-type="pmid">32872154</pub-id></citation></ref>
<ref id="B13">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Bonaccorsi</surname> <given-names>G.</given-names></name> <name><surname>Pierri</surname> <given-names>F.</given-names></name> <name><surname>Cinelli</surname> <given-names>M.</given-names></name> <name><surname>Flori</surname> <given-names>A.</given-names></name> <name><surname>Galeazzi</surname> <given-names>A.</given-names></name> <name><surname>Porcelli</surname> <given-names>F.</given-names></name> <etal/></person-group>. (<year>2020</year>). <article-title>Economic and social consequences of human mobility restrictions under COVID-19</article-title>. <source>Proc. Natl. Acad. Sci. U.S.A.</source> <volume>117</volume>, <fpage>15530</fpage>&#x02013;<lpage>15535</lpage>. <pub-id pub-id-type="doi">10.1073/pnas.2007658117</pub-id><pub-id pub-id-type="pmid">32554604</pub-id></citation></ref>
<ref id="B14">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Bray</surname> <given-names>S. R.</given-names></name> <name><surname>Born</surname> <given-names>H. A.</given-names></name></person-group> (<year>2004</year>). <article-title>Transition to university and vigorous physical activity: implications for health and psychological well-being</article-title>. <source>J. Am. Coll. Heal.</source> <volume>52</volume>, <fpage>181</fpage>&#x02013;<lpage>188</lpage>. <pub-id pub-id-type="doi">10.3200/JACH.52.4.181-188</pub-id><pub-id pub-id-type="pmid">15018429</pub-id></citation></ref>
<ref id="B15">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Bull</surname> <given-names>F. C.</given-names></name> <name><surname>Al-Ansari</surname> <given-names>S. S.</given-names></name> <name><surname>Biddle</surname> <given-names>S.</given-names></name> <name><surname>Borodulin</surname> <given-names>K.</given-names></name> <name><surname>Buman</surname> <given-names>M. P.</given-names></name> <name><surname>Cardon</surname> <given-names>G.</given-names></name> <etal/></person-group>. (<year>2020</year>). <article-title>World health organization 2020 guidelines on physical activity and sedentary behaviour</article-title>. <source>Br. J. Sports Med.</source> <volume>54</volume>, <fpage>1451</fpage>&#x02013;<lpage>1462</lpage>. <pub-id pub-id-type="doi">10.1136/bjsports-2020-102955</pub-id><pub-id pub-id-type="pmid">33239350</pub-id></citation></ref>
<ref id="B16">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Burtscher</surname> <given-names>J.</given-names></name> <name><surname>Burtscher</surname> <given-names>M.</given-names></name> <name><surname>Millet</surname> <given-names>G. P.</given-names></name></person-group> (<year>2020</year>). <article-title>(Indoor) isolation, stress, and physical inactivity: vicious circles accelerated by COVID-19?</article-title> <source>Scand. J. Med. Sci. Sport</source> <volume>30</volume>, <fpage>1544</fpage>&#x02013;<lpage>1545</lpage>. <pub-id pub-id-type="doi">10.1111/sms.13706</pub-id><pub-id pub-id-type="pmid">32374894</pub-id></citation></ref>
<ref id="B17">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Calestine</surname> <given-names>J.</given-names></name> <name><surname>Bopp</surname> <given-names>M.</given-names></name> <name><surname>Bopp</surname> <given-names>C. M.</given-names></name> <name><surname>Papalia</surname> <given-names>Z.</given-names></name></person-group> (<year>2017</year>). <article-title>College student work habits are related to physical activity and fitness</article-title>. <source>Int. J. Exerc. Sci.</source> <volume>10</volume>, <fpage>1009</fpage>&#x02013;<lpage>1017</lpage>.<pub-id pub-id-type="pmid">29170702</pub-id></citation></ref>
<ref id="B18">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Casta&#x000F1;eda-Babarro</surname> <given-names>A.</given-names></name> <name><surname>Coca</surname> <given-names>A.</given-names></name> <name><surname>Arbillaga-Etxarri</surname> <given-names>A.</given-names></name> <name><surname>Guti&#x000E9;rrez-Santamar&#x000ED;a</surname> <given-names>B.</given-names></name></person-group> (<year>2020</year>). <article-title>Physical activity change during COVID-19 confinement</article-title>. <source>Int. J. Environ. Res. Public Health</source> <volume>17</volume>:<fpage>6878</fpage>. <pub-id pub-id-type="doi">10.3390/ijerph17186878</pub-id><pub-id pub-id-type="pmid">32967091</pub-id></citation></ref>
<ref id="B19">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Chtourou</surname> <given-names>H.</given-names></name> <name><surname>Trabelsi</surname> <given-names>K.</given-names></name> <name><surname>H&#x00027;mida</surname> <given-names>C.</given-names></name> <name><surname>Boukhris</surname> <given-names>O.</given-names></name> <name><surname>Glenn</surname> <given-names>J. M.</given-names></name> <name><surname>Brach</surname> <given-names>M.</given-names></name> <etal/></person-group>. (<year>2020</year>). <article-title>Staying physically active during the quarantine and self-isolation period for controlling and mitigating the COVID-19 pandemic: a systematic overview of the literature</article-title>. <source>Front. Psychol.</source> <volume>11</volume>:<fpage>1708</fpage>. <pub-id pub-id-type="doi">10.3389/fpsyg.2020.01708</pub-id><pub-id pub-id-type="pmid">33013497</pub-id></citation></ref>
<ref id="B20">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Crombie</surname> <given-names>A. P.</given-names></name> <name><surname>Ilich</surname> <given-names>J. Z.</given-names></name> <name><surname>Dutton</surname> <given-names>G. R.</given-names></name> <name><surname>Panton</surname> <given-names>L. B.</given-names></name> <name><surname>Abood</surname> <given-names>D. A.</given-names></name></person-group> (<year>2009</year>). <article-title>The freshman weight gain phenomenon revisited</article-title>. <source>Nutr. Rev.</source> <volume>67</volume>, <fpage>83</fpage>&#x02013;<lpage>94</lpage>. <pub-id pub-id-type="doi">10.1111/j.1753-4887.2008.00143.x</pub-id><pub-id pub-id-type="pmid">19178649</pub-id></citation></ref>
<ref id="B21">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Deng</surname> <given-names>C. H.</given-names></name> <name><surname>Wang</surname> <given-names>J. Q.</given-names></name> <name><surname>Zhu</surname> <given-names>L. M.</given-names></name> <name><surname>Liu</surname> <given-names>H. W.</given-names></name> <name><surname>Guo</surname> <given-names>Y.</given-names></name> <name><surname>Peng</surname> <given-names>X. H.</given-names></name> <etal/></person-group>. (<year>2020</year>). <article-title>Association of web-based physical education with mental health of college students in wuhan during the COVID-19 outbreak: cross-sectional survey study</article-title>. <source>J. Med. Internet Res.</source> <volume>22</volume>:<fpage>e21301</fpage>. <pub-id pub-id-type="doi">10.2196/21301</pub-id><pub-id pub-id-type="pmid">32997639</pub-id></citation></ref>
<ref id="B22">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Ding</surname> <given-names>D.</given-names></name> <name><surname>Lawson</surname> <given-names>K. D.</given-names></name> <name><surname>Kolbe-Alexander</surname> <given-names>T. L.</given-names></name> <name><surname>Finkelstein</surname> <given-names>E. A.</given-names></name> <name><surname>Katzmarzyk</surname> <given-names>P. T.</given-names></name> <name><surname>van Mechelen</surname> <given-names>W.</given-names></name> <etal/></person-group>. (<year>2016</year>). <article-title>The economic burden of physical inactivity: a global analysis of major non-communicable diseases</article-title>. <source>Lancet</source> <volume>388</volume>, <fpage>1311</fpage>&#x02013;<lpage>1324</lpage>. <pub-id pub-id-type="doi">10.1016/S0140-6736(16)30383-X</pub-id><pub-id pub-id-type="pmid">27475266</pub-id></citation></ref>
<ref id="B23">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Du</surname> <given-names>Y.</given-names></name> <name><surname>Liu</surname> <given-names>B.</given-names></name> <name><surname>Sun</surname> <given-names>Y.</given-names></name> <name><surname>Snetselaar</surname> <given-names>L. G.</given-names></name> <name><surname>Wallace</surname> <given-names>R. B.</given-names></name> <name><surname>Bao</surname> <given-names>W.</given-names></name></person-group> (<year>2019</year>). <article-title>Trends in adherence to the physical activity guidelines for americans for aerobic activity and time spent on sedentary behavior among US adults, 2007 to 2016</article-title>. <source>JAMA Netw. Open</source> <volume>2</volume>:<fpage>e197597</fpage>. <pub-id pub-id-type="doi">10.1001/jamanetworkopen.2019.7597</pub-id><pub-id pub-id-type="pmid">31348504</pub-id></citation></ref>
<ref id="B24">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Dunton</surname> <given-names>G. F.</given-names></name> <name><surname>Do</surname> <given-names>B.</given-names></name> <name><surname>Wang</surname> <given-names>S. D.</given-names></name></person-group> (<year>2020</year>). <article-title>Early effects of the COVID-19 pandemic on physical activity and sedentary behavior in children living in the U.S</article-title>. <source>BMC Public Health</source> <volume>2</volume>:<fpage>1351</fpage>. <pub-id pub-id-type="doi">10.1186/s12889-020-09429-3</pub-id></citation></ref>
<ref id="B25">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Gall&#x000E8;</surname> <given-names>F.</given-names></name> <name><surname>Sabella</surname> <given-names>E. A.</given-names></name> <name><surname>Ferracuti</surname> <given-names>S.</given-names></name> <name><surname>De Giglio</surname> <given-names>O.</given-names></name> <name><surname>Caggiano</surname> <given-names>G.</given-names></name> <name><surname>Protano</surname> <given-names>C.</given-names></name> <etal/></person-group>. (<year>2020</year>). <article-title>Sedentary behaviors and physical activity of Italian undergraduate students during lockdown at the time of COVID&#x02212;19 pandemic</article-title>. <source>Int. J. Environ. Res. Public Health</source> <volume>17</volume>:<fpage>6171</fpage>. <pub-id pub-id-type="doi">10.3390/ijerph17176171</pub-id><pub-id pub-id-type="pmid">32854414</pub-id></citation></ref>
<ref id="B26">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Gallo</surname> <given-names>L. A.</given-names></name> <name><surname>Gallo</surname> <given-names>T. F.</given-names></name> <name><surname>Young</surname> <given-names>S. L.</given-names></name> <name><surname>Moritz</surname> <given-names>K. M.</given-names></name> <name><surname>Akison</surname> <given-names>L. K.</given-names></name></person-group> (<year>2020</year>). <article-title>The impact of isolation measures due to Covid-19 on energy intake and physical activity levels in Australian university students</article-title>. <source>Nutrients</source> <volume>12</volume>:<fpage>1865</fpage>. <pub-id pub-id-type="doi">10.3390/nu12061865</pub-id><pub-id pub-id-type="pmid">32585830</pub-id></citation></ref>
<ref id="B27">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Guo</surname> <given-names>Y.</given-names></name> <name><surname>Cheng</surname> <given-names>C.</given-names></name> <name><surname>Zeng</surname> <given-names>Y.</given-names></name> <name><surname>Li</surname> <given-names>Y.</given-names></name> <name><surname>Zhu</surname> <given-names>M.</given-names></name> <name><surname>Yang</surname> <given-names>W.</given-names></name> <etal/></person-group>. (<year>2020</year>). <article-title>Mental health disorders and associated risk factors in quarantined adults during the COVID-19 outbreak in China: cross-sectional study</article-title>. <source>J. Med. Internet Res.</source> <volume>22</volume>:<fpage>e20328</fpage>. <pub-id pub-id-type="doi">10.2196/20328</pub-id><pub-id pub-id-type="pmid">32716899</pub-id></citation></ref>
<ref id="B28">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Guthold</surname> <given-names>R.</given-names></name> <name><surname>Stevens</surname> <given-names>G. A.</given-names></name> <name><surname>Riley</surname> <given-names>L. M.</given-names></name> <name><surname>Bull</surname> <given-names>F. C.</given-names></name></person-group> (<year>2018</year>). <article-title>Worldwide trends in insufficient physical activity from 2001 to 2016: a pooled analysis of 358 population-based surveys with 1&#x000B7;9 million participants</article-title>. <source>Lancet Glob. Heal.</source> <volume>6</volume>, <fpage>e1077</fpage>&#x02013;<lpage>e1086</lpage>. <pub-id pub-id-type="doi">10.1016/S2214-109X(18)30357-7</pub-id><pub-id pub-id-type="pmid">30193830</pub-id></citation></ref>
<ref id="B29">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Guyatt</surname> <given-names>G. H.</given-names></name> <name><surname>Oxman</surname> <given-names>A. D.</given-names></name> <name><surname>Sch&#x000FC;nemann</surname> <given-names>H. J.</given-names></name> <name><surname>Tugwell</surname> <given-names>P.</given-names></name> <name><surname>Knottnerus</surname> <given-names>A.</given-names></name></person-group> (<year>2011</year>). <article-title>GRADE guidelines: a new series of articles in the journal of clinical epidemiology</article-title>. <source>J. Clin. Epidemiol.</source> <volume>64</volume>, <fpage>380</fpage>&#x02013;<lpage>382</lpage>. <pub-id pub-id-type="doi">10.1016/j.jclinepi.2010.09.011</pub-id><pub-id pub-id-type="pmid">21185693</pub-id></citation></ref>
<ref id="B30">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Hall</surname> <given-names>G.</given-names></name> <name><surname>Laddu</surname> <given-names>D. R.</given-names></name> <name><surname>Phillips</surname> <given-names>S. A.</given-names></name> <name><surname>Lavie</surname> <given-names>C. J.</given-names></name> <name><surname>Arena</surname> <given-names>R.</given-names></name></person-group> (<year>2020</year>). <article-title>A tale of two pandemics: how will COVID-19 and global trends in physical inactivity and sedentary behavior affect one another?</article-title> <source>Prog. Cardiovasc. Dis</source>. <pub-id pub-id-type="doi">10.1016/j.pcad.2020.04.005</pub-id>. [Epub ahead of print].<pub-id pub-id-type="pmid">32277997</pub-id></citation></ref>
<ref id="B31">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Holingue</surname> <given-names>C.</given-names></name> <name><surname>Badillo-Goicoechea</surname> <given-names>E.</given-names></name> <name><surname>Riehm</surname> <given-names>K. E.</given-names></name> <name><surname>Veldhuis</surname> <given-names>C. B.</given-names></name> <name><surname>Thrul</surname> <given-names>J.</given-names></name> <name><surname>Johnson</surname> <given-names>R. M.</given-names></name> <etal/></person-group>. (<year>2020</year>). <article-title>Mental distress during the COVID-19 pandemic among US adults without a pre-existing mental health condition: findings from American trend panel survey</article-title>. <source>Prev. Med.</source> <volume>139</volume>:<fpage>106231</fpage>. <pub-id pub-id-type="doi">10.1016/j.ypmed.2020.106231</pub-id><pub-id pub-id-type="pmid">32758507</pub-id></citation></ref>
<ref id="B32">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Jiao</surname> <given-names>W. Y.</given-names></name> <name><surname>Wang</surname> <given-names>L. N.</given-names></name> <name><surname>Liu</surname> <given-names>J.</given-names></name> <name><surname>Fang</surname> <given-names>S. F.</given-names></name> <name><surname>Jiao</surname> <given-names>F. Y.</given-names></name> <name><surname>Pettoello-Mantovani</surname> <given-names>M.</given-names></name> <etal/></person-group>. (<year>2020</year>). <article-title>Behavioral and emotional disorders in children during the COVID-19 epidemic</article-title>. <source>J. Pediatr.</source> <volume>221</volume>, <fpage>264</fpage>&#x02013;<lpage>266.e1</lpage>. <pub-id pub-id-type="doi">10.1016/j.jpeds.2020.03.013</pub-id><pub-id pub-id-type="pmid">32248989</pub-id></citation></ref>
<ref id="B33">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Jung</surname> <given-names>M. E.</given-names></name> <name><surname>Bray</surname> <given-names>S. R.</given-names></name> <name><surname>Ginis</surname> <given-names>K. A. M.</given-names></name></person-group> (<year>2008</year>). <article-title>Behavior change and the freshman 15: tracking physical activity and dietary patterns in 1st-year university women</article-title>. <source>J. Am. Coll. Heal.</source> <volume>56</volume>, <fpage>523</fpage>&#x02013;<lpage>530</lpage>. <pub-id pub-id-type="doi">10.3200/JACH.56.5.523-530</pub-id><pub-id pub-id-type="pmid">18400664</pub-id></citation></ref>
<ref id="B34">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Karuc</surname> <given-names>J.</given-names></name> <name><surname>Sori&#x00107;</surname> <given-names>M.</given-names></name> <name><surname>Radman</surname> <given-names>I.</given-names></name> <name><surname>Mi&#x00161;igoj-Durakovi&#x00107;</surname> <given-names>M.</given-names></name></person-group> (<year>2020</year>). <article-title>Moderators of change in physical activity levels during restrictions due to COVID-19 pandemic in young urban adults</article-title>. <source>Sustainability</source> <volume>12</volume>:<fpage>6392</fpage>. <pub-id pub-id-type="doi">10.3390/su12166392</pub-id></citation></ref>
<ref id="B35">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Kwan</surname> <given-names>M. Y.</given-names></name> <name><surname>Cairney</surname> <given-names>J.</given-names></name> <name><surname>Faulkner</surname> <given-names>G. E.</given-names></name> <name><surname>Pullenayegum</surname> <given-names>E. E.</given-names></name></person-group> (<year>2012</year>). <article-title>Physical activity and other health-risk behaviors during the transition into early adulthood: a longitudinal cohort study</article-title>. <source>Am. J. Prev. Med.</source> <volume>42</volume>, <fpage>14</fpage>&#x02013;<lpage>20</lpage>. <pub-id pub-id-type="doi">10.1016/j.amepre.2011.08.026</pub-id><pub-id pub-id-type="pmid">22176841</pub-id></citation></ref>
<ref id="B36">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Lee</surname> <given-names>I.-M. M.</given-names></name> <name><surname>Shiroma</surname> <given-names>E. J.</given-names></name> <name><surname>Lobelo</surname> <given-names>F.</given-names></name> <name><surname>Puska</surname> <given-names>P.</given-names></name> <name><surname>Blair</surname> <given-names>S. N.</given-names></name> <name><surname>Katzmarzyk</surname> <given-names>P. T.</given-names></name> <etal/></person-group>. (<year>2012</year>). <article-title>Effect of physical inactivity on major non-communicable diseases worldwide: an analysis of burden of disease and life expectancy</article-title>. <source>Lancet</source> <volume>380</volume>, <fpage>219</fpage>&#x02013;<lpage>229</lpage>. <pub-id pub-id-type="doi">10.1016/S0140-6736(12)61031-9</pub-id><pub-id pub-id-type="pmid">22818936</pub-id></citation></ref>
<ref id="B37">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Lewnard</surname> <given-names>J. A.</given-names></name> <name><surname>Lo</surname> <given-names>N. C.</given-names></name></person-group> (<year>2020</year>). <article-title>Scientific and ethical basis for social-distancing interventions against COVID-19</article-title>. <source>Lancet Infect. Dis.</source> <volume>20</volume>, <fpage>631</fpage>&#x02013;<lpage>633</lpage>. <pub-id pub-id-type="doi">10.1016/S1473-3099(20)30190-0</pub-id><pub-id pub-id-type="pmid">32213329</pub-id></citation></ref>
<ref id="B38">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Lim</surname> <given-names>S. S.</given-names></name> <name><surname>Vos</surname> <given-names>T.</given-names></name> <name><surname>Flaxman</surname> <given-names>A. D.</given-names></name> <name><surname>Danaei</surname> <given-names>G.</given-names></name> <name><surname>Shibuya</surname> <given-names>K.</given-names></name> <name><surname>Adair-Rohani</surname> <given-names>H.</given-names></name> <etal/></person-group>. (<year>2012</year>). <article-title>A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990-2010: a systematic analysis for the global burden of disease study 2010</article-title>. <source>Lancet</source> <volume>380</volume>, <fpage>2224</fpage>&#x02013;<lpage>2260</lpage>. <pub-id pub-id-type="doi">10.1016/S0140-6736(12)61766-8</pub-id><pub-id pub-id-type="pmid">23245609</pub-id></citation></ref>
<ref id="B39">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Lo</surname> <given-names>C. K. L.</given-names></name> <name><surname>Mertz</surname> <given-names>D.</given-names></name> <name><surname>Loeb</surname> <given-names>M.</given-names></name></person-group> (<year>2014</year>). <article-title>Newcastle-ottawa scale: comparing reviewers&#x00027; to authors&#x00027; assessments</article-title>. <source>BMC Med. Res. Methodol.</source> <volume>14</volume>:<fpage>45</fpage>. <pub-id pub-id-type="doi">10.1186/1471-2288-14-45</pub-id><pub-id pub-id-type="pmid">24690082</pub-id></citation></ref>
<ref id="B40">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Maher</surname> <given-names>J. P.</given-names></name> <name><surname>Hevel</surname> <given-names>D. J.</given-names></name> <name><surname>Reifsteck</surname> <given-names>E. J.</given-names></name> <name><surname>Drollette</surname> <given-names>E. S.</given-names></name></person-group> (<year>2020</year>). <article-title>Physical activity is positively associated with college students&#x00027; positive affect regardless of stressful life events during the COVID-19 pandemic</article-title>. <source>Psychol. Sport Exerc.</source> <volume>52</volume>:<fpage>101826</fpage>. <pub-id pub-id-type="doi">10.1016/j.psychsport.2020.101826</pub-id><pub-id pub-id-type="pmid">33100905</pub-id></citation></ref>
<ref id="B41">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Mattioli</surname> <given-names>A. V.</given-names></name> <name><surname>Ballerini Puviani</surname> <given-names>M.</given-names></name> <name><surname>Nasi</surname> <given-names>M.</given-names></name> <name><surname>Farinetti</surname> <given-names>A.</given-names></name></person-group> (<year>2020</year>). <article-title>COVID-19 pandemic: the effects of quarantine on cardiovascular risk</article-title>. <source>Eur. J. Clin. Nutr.</source> <volume>74</volume>, <fpage>852</fpage>&#x02013;<lpage>855</lpage>. <pub-id pub-id-type="doi">10.1038/s41430-020-0646-z</pub-id><pub-id pub-id-type="pmid">32371988</pub-id></citation></ref>
<ref id="B42">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Moher</surname> <given-names>D.</given-names></name> <name><surname>Liberati</surname> <given-names>A.</given-names></name> <name><surname>Tetzlaff</surname> <given-names>J.</given-names></name> <name><surname>Altman</surname> <given-names>D. G.</given-names></name> <collab>PRISMA Group</collab></person-group> (<year>2009</year>). <article-title>Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement</article-title>. <source>PLoS Med.</source> <volume>6</volume>:<fpage>e1000097</fpage>. <pub-id pub-id-type="doi">10.1371/journal.pmed.1000097</pub-id></citation></ref>
<ref id="B43">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Natalucci</surname> <given-names>V.</given-names></name> <name><surname>Carnevale Pellino</surname> <given-names>V.</given-names></name> <name><surname>Barbieri</surname> <given-names>E.</given-names></name> <name><surname>Vandoni</surname> <given-names>M.</given-names></name></person-group> (<year>2020</year>). <article-title>Is it important to perform physical activity during coronavirus pandemic (COVID-19)? Driving action for a correct exercise plan</article-title>. <source>Front. Public Heal.</source> <volume>8</volume>:<fpage>602020</fpage>. <pub-id pub-id-type="doi">10.3389/fpubh.2020.602020</pub-id><pub-id pub-id-type="pmid">33224923</pub-id></citation></ref>
<ref id="B44">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Pengpid</surname> <given-names>S.</given-names></name> <name><surname>Peltzer</surname> <given-names>K.</given-names></name> <name><surname>Kassean</surname> <given-names>H. K.</given-names></name> <name><surname>Tsala Tsala</surname> <given-names>J. P.</given-names></name> <name><surname>Sychareun</surname> <given-names>V.</given-names></name> <name><surname>M&#x000FC;ller-Riemenschneider</surname> <given-names>F.</given-names></name></person-group> (<year>2015</year>). <article-title>Physical inactivity and associated factors among university students in 23 low-, middle- and high-income countries</article-title>. <source>Int. J. Public Health</source> <volume>60</volume>, <fpage>539</fpage>&#x02013;<lpage>549</lpage>. <pub-id pub-id-type="doi">10.1007/s00038-015-0680-0</pub-id><pub-id pub-id-type="pmid">25926342</pub-id></citation></ref>
<ref id="B45">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Pullman</surname> <given-names>A. W.</given-names></name> <name><surname>Masters</surname> <given-names>R. C.</given-names></name> <name><surname>Zalot</surname> <given-names>L. C.</given-names></name> <name><surname>Carde</surname> <given-names>L. E.</given-names></name> <name><surname>Saraiva</surname> <given-names>M. M.</given-names></name> <name><surname>Dam</surname> <given-names>Y. Y.</given-names></name> <etal/></person-group>. (<year>2009</year>). <article-title>Effect of the transition from high school to university on anthropometric and lifestyle variables in males</article-title>. <source>Appl. Physiol. Nutr. Metab.</source> <volume>34</volume>, <fpage>162</fpage>&#x02013;<lpage>171</lpage>. <pub-id pub-id-type="doi">10.1139/H09-007</pub-id><pub-id pub-id-type="pmid">19370046</pub-id></citation></ref>
<ref id="B46">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Romero-Blanco</surname> <given-names>C.</given-names></name> <name><surname>Rodr&#x000ED;guez-Almagro</surname> <given-names>J.</given-names></name> <name><surname>Onieva-Zafra</surname> <given-names>M. D.</given-names></name> <name><surname>Parra-Fern&#x000E1;ndez</surname> <given-names>M. L.</given-names></name> <name><surname>del Carmen Prado-Laguna</surname> <given-names>M.</given-names></name> <name><surname>Hern&#x000E1;ndez-Mart&#x000ED;nez</surname> <given-names>A.</given-names></name></person-group> (<year>2020</year>). <article-title>Physical activity and sedentary lifestyle in university students: changes during confinement due to the COVID-19 pandemic</article-title>. <source>Int. J. Environ. Res. Public Health</source> <volume>17</volume>:<fpage>6567</fpage>. <pub-id pub-id-type="doi">10.3390/ijerph17186567</pub-id><pub-id pub-id-type="pmid">32916972</pub-id></citation></ref>
<ref id="B47">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Sa&#x000F1;udo</surname> <given-names>B.</given-names></name> <name><surname>Fennell</surname> <given-names>C.</given-names></name> <name><surname>S&#x000E1;nchez-Oliver</surname> <given-names>A. J.</given-names></name></person-group> (<year>2020</year>). <article-title>Objectively-assessed physical activity, sedentary behavior, smartphone use, and sleep patterns pre and during-COVID-19 quarantine in young adults from Spain</article-title>. <source>Sustainability</source> <volume>12</volume>:<fpage>5890</fpage>. <pub-id pub-id-type="doi">10.3390/su12155890</pub-id></citation></ref>
<ref id="B48">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Savage</surname> <given-names>M. J.</given-names></name> <name><surname>James</surname> <given-names>R.</given-names></name> <name><surname>Magistro</surname> <given-names>D.</given-names></name> <name><surname>Donaldson</surname> <given-names>J.</given-names></name> <name><surname>Healy</surname> <given-names>L. C.</given-names></name> <name><surname>Nevill</surname> <given-names>M.</given-names></name> <etal/></person-group>. (<year>2020</year>). <article-title>Mental health and movement behaviour during the COVID-19 pandemic in UK university students: prospective cohort study</article-title>. <source>Ment. Health Phys. Act.</source> <volume>19</volume>:<fpage>100357</fpage>. <pub-id pub-id-type="doi">10.1016/j.mhpa.2020.100357</pub-id></citation></ref>
<ref id="B49">
<citation citation-type="book"><person-group person-group-type="author"><collab>U.S. Department of Health and Human Services</collab></person-group> (<year>2018</year>). <source>Physical Activity Guidelines for Americans, 2nd edition</source>. <publisher-loc>Washington, DC</publisher-loc>: <publisher-name>US Department of Health and Human Services</publisher-name>.</citation></ref>
<ref id="B50">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Van Dyck</surname> <given-names>D.</given-names></name> <name><surname>De Bourdeaudhuij</surname> <given-names>I.</given-names></name> <name><surname>Deliens</surname> <given-names>T.</given-names></name> <name><surname>Deforche</surname> <given-names>B.</given-names></name></person-group> (<year>2015</year>). <article-title>Can changes in psychosocial factors and residency explain the decrease in physical activity during the transition from high school to college or university?</article-title> <source>Int. J. Behav. Med.</source> <volume>22</volume>, <fpage>178</fpage>&#x02013;<lpage>186</lpage>. <pub-id pub-id-type="doi">10.1007/s12529-014-9424-4</pub-id></citation></ref>
<ref id="B51">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>van Tilburg</surname> <given-names>T. G.</given-names></name> <name><surname>Steinmetz</surname> <given-names>S.</given-names></name> <name><surname>Stolte</surname> <given-names>E.</given-names></name> <name><surname>van der Roest</surname> <given-names>H.</given-names></name> <name><surname>de Vries</surname> <given-names>D. H.</given-names></name></person-group> (<year>2020</year>). <article-title>Loneliness and mental health during the COVID-19 pandemic: a study among dutch older adults</article-title>. <source>J. Gerontol. B Psychol. Sci. Soc. Sci.</source> <pub-id pub-id-type="doi">10.1093/geronb/gbaa111</pub-id>. [Epub ahead of print].<pub-id pub-id-type="pmid">32756931</pub-id></citation></ref>
<ref id="B52">
<citation citation-type="journal"><person-group person-group-type="author"><name><surname>Viana</surname> <given-names>R. B.</given-names></name> <name><surname>de Lira</surname> <given-names>C. A. B.</given-names></name></person-group> (<year>2020</year>). <article-title>Exergames as coping strategies for anxiety disorders during the COVID-19 quarantine period</article-title>. <source>Games Health J.</source> <volume>9</volume>, <fpage>147</fpage>&#x02013;<lpage>149</lpage>. <pub-id pub-id-type="doi">10.1089/g4h.2020.0060</pub-id><pub-id pub-id-type="pmid">32375011</pub-id></citation></ref>
<ref id="B53">
<citation citation-type="web"><person-group person-group-type="author"><name><surname>Wells</surname> <given-names>G.</given-names></name> <name><surname>Shea</surname> <given-names>B.</given-names></name> <name><surname>O&#x00027;Connell</surname> <given-names>D.</given-names></name> <name><surname>Peterson</surname> <given-names>J.</given-names></name> <name><surname>Welch</surname> <given-names>V.</given-names></name> <name><surname>Losos</surname> <given-names>M.</given-names></name> <etal/></person-group> (<year>2012</year>). <source>The Newcastle-Ottawa Scale (NOS) for Assessing the Quality of Nonrandomised Studies in Meta-Analyses</source>. Available online at: <ext-link ext-link-type="uri" xlink:href="http://www.ohri.ca/programs/clinical_epidemiology/oxford.asp">http://www.ohri.ca/programs/clinical_epidemiology/oxford.asp</ext-link> (accessed October 24, 2020).</citation></ref>
<ref id="B54">
<citation citation-type="web"><person-group person-group-type="author"><collab>World Health Organization</collab></person-group> (<year>2018</year>). <source>Physical Inactivity: A Global Public Health Problem</source>. Available online at: <ext-link ext-link-type="uri" xlink:href="https://www.who.int/ncds/prevention/physical-activity/inactivity-global-health-problem/en/">https://www.who.int/ncds/prevention/physical-activity/inactivity-global-health-problem/en/</ext-link> (accessed October 24, 2020).</citation></ref>
<ref id="B55">
<citation citation-type="web"><person-group person-group-type="author"><collab>World Health Organization</collab></person-group> (<year>2020a</year>). <source>WHO Coronavirus Disease (COVID-19) Dashboard</source>. Available online at: <ext-link ext-link-type="uri" xlink:href="https://covid19.who.int/">https://covid19.who.int/</ext-link> (accessed October 24, 2020).</citation></ref>
<ref id="B56">
<citation citation-type="web"><person-group person-group-type="author"><collab>World Health Organization</collab></person-group> (<year>2020b</year>). <source>WHO Director-General&#x00027;s Opening Remarks at the Media Briefing on COVID-19 - 12 October 2020</source>. Available online at: <ext-link ext-link-type="uri" xlink:href="https://www.who.int/director-general/speeches/detail/who-director-general-s-opening-remarks-at-the-media-briefing-on-covid-19-&#x02212;12-october-2020">https://www.who.int/director-general/speeches/detail/who-director-general-s-opening-remarks-at-the-media-briefing-on-covid-19-&#x02212;12-october-2020</ext-link> (accessed October 24, 2020).</citation></ref>
</ref-list> 
</back>
</article>