Integrating physical activity (PA) into the curriculum and teaching in schools is defined as physically active learning (PAL) (1). Interventions have reported increased PA levels in pupils, with average values ranging from an additional 1 to 14 min of moderate-to-vigorous PA (MVPA) (2–8). In addition, positive effects have been reported on academic performance, mental health and vitality, and cognitive skills (1, 2, 4, 9, 10). PAL is, therefore, viewed as an important method for providing opportunities for pupils to accumulate the recommended average amount of 60 min/day of MVPA for children and adolescents advocated by the World Health Organization (WHO) (11). However, such interventions have been criticized for having limited sustainability beyond the experimental program due to poor theoretical framing, weak implementation, low adherence among teachers, and/or limited attention to real-world contexts (12, 13). Real-world contexts are here understood as the everyday practice of teaching where teachers organize their teaching according to their own purpose, values, and beliefs (14).

Against the expanding body of PAL research in educational contexts, experimental studies have been the more prevalent forms of study design compared to real-world observational studies (13). Experimental studies can be characterized as interventions designed primarily by researchers to increase PA opportunities through PAL and study the effects of specific interventions. Real-world studies, on the other hand, may be characterized as observations of PAL teaching enacted by experienced teachers who have sustained PAL as a regular part of their teaching practice (14). This may take into consideration teachers' perspectives in designing and sustaining PAL in their everyday teaching practice without scientific instructions from researchers (12, 13). Utilizing experiences from teachers who have sustained PAL in their practice beyond experimental programs is valuable to gain knowledge of PAL enactment and the corresponding PA levels in real-world practices (14, 15).

A large majority of interventions that have implemented PAL and assessed PA levels have been researcher-led, primarily with a strict randomized controlled trial design (13). Vazou et al. (13) highlighted that researcher-led interventions do not necessarily reflect a real-world context and restrict the autonomy of teachers to facilitate PAL. Furthermore, these studies may undermine the particular school context and several barriers among the teachers (e.g., lack of time and perceived value and competence of PAL enactment) (16–21). Recent studies also highlight that the primary focus of the teachers is the academic content and learning processes, rather than the amount and intensity of PA (16, 17). The coherency of academic content, PAL enactment, and PA levels and intensity has gained less attention in the previous literature, especially among teachers who have sustained PAL in their practice (12). Findings drawn from experimental studies may, therefore, not necessarily reflect pupils’ PA levels and intensities during PAL that are applicable and sustainable in a real-world context (12, 13).

There is an increasing body of knowledge on teachers' perceptions and experiences with enacting PAL in real-world teaching (17–19). However, to the best of our knowledge, no previous studies have examined the relationship between how the academic content, organization, and PA levels might look in real-world enactment of PAL in teaching. Since several PA programs in schools, including PAL, have proved ineffective (8, 10, 12, 22, 23), and teachers repeatedly have reported a greater concern for learning outcomes compared to PA levels (16–19), it is important to explore how PAL is enacted in the real world, focusing on the academic content, organization and PA levels, in schools with long experience with PAL enactment. In-depth investigations of experienced PAL teachers in case studies might provide a broad understanding of how PAL may be enacted when sustained in real-world practices. Such case studies can provide new perspectives and refine our current understanding of PAL enactment by taking into account the pedagogical perspectives of studied teachers and the specific school context (24). Knowledge derived from such studies may help guide future research designs for providing sustainable PAL programs and PA promotion in schools.

Against this background, in-depth investigations of experienced teachers and their enactment of PAL may contribute to novel and important insights into how academic content, PAL organization, and PA levels and intensity are related. Thus, this case study aimed to observe and describe the organization and content of a variety of PAL teaching situations and describe the corresponding PA levels when experienced teachers enacted PAL in their real-world practice.

In total, structured observations and objectively assessed PA were obtained from 37 school lessons where PAL was enacted in teaching (first grade, 12 lessons; sixth grade, 15 lessons; eighth grade, 10 lessons). The teachers planned and performed PAL 2–3 times per week, in subjects related to Norwegian language (n = 8), English language (n = 13), and mathematics (n = 16). PAL was typically enacted as a segment and combined with more traditional, sedentary, and classroom-based teaching. However, in three instances, PAL was enacted as a whole lesson (±45 min) (one in first grade and two in sixth grade; see Supplementary Tables 1 and 2).

Observations of enacted PAL are summarized in Figures 1A–C. The primary movement selected by the teacher was mainly running or walking (Figure 1A). The two segments of PAL that were categorized with bodily movements related to different strength exercises, were both observed in 8th grade. Generally, the percentage of time spent in MVPA and total PA was 12.2% (SE = 0.8, 95% CI = 10.7, 13.9) and 17.9% (SE = 1.4, 95% CI = 15.2, 20.6) higher, respectively, and 15.8% (SE = 1.4, 95% CI = 13.1, 18.4) lower percentages of SED in PAL that included running compared to PAL where walking was a primary movement (Supplementary Tables 1–3). Primarily, the teachers also organized tasks and PAL activities as group work (83.7%, Figure 1B) and did not provide competitive instructions in most PAL teaching (Figure 1C). The only session that was organized as a competitive game intentionally by the teacher was conducted in first grade.

The general characteristics of PA in PAL are presented in Table 2. On average, PAL segments generated 9.8 ± 4.0 min of total PA (LPA + MVPA) ranging from 0.1 to 26.9 min. Generally, PAL segments were mainly dominated by SED (57.8% ± 15.7%; range: 18.8%–99.8%), while LPA, MPA, and VPA contributed with 22.9% ± 7.5% (range: 0.1%–45.9%), 8.1% ± 4.6% (range: 0.0%–27.9%), and 11.1 ± 7.3% (range: 0.0%–43.5%) of each PAL segment, respectively.

There were negligible differences between classes in total PA in minutes (9.7 ± 3.3 min, 9.9 ± 4.6 min, and 9.8 ± 3.9 min for the first, sixth, and eighth grade, respectively) or in the number of minutes spent in the different PA intensities (LPA, MPA, VPA, or MVPA; Table 2). However, the sixth grade displayed higher amounts of SED (+8.0 and +7.0%, +4.7 and +5.3 min) and a lower percentage of LPA (−3.2% and −1.7%) and MVPA (−4.7% and −5.0%) compared to the first and eighth grade, respectively (Table 2).

Table 3 presents the descriptive information on PA characteristics during PAL conducted in different locations (outdoor, indoor, and inside the classroom). In general, classroom-based PAL generated higher relative values of SED (+11.5% and +9.4% higher compared to indoor and outdoor PAL, respectively) both when the data were pooled and within each class (Table 3). Indoor-based (+8.9%) and/or outdoor-based (6.9%) PAL generated more PA at higher intensities (i.e., MVPA) compared to classroom-based PAL.

The large variation coefficients presented in Table 2 reveal a great variation in PA levels across PAL. To depict the variation between lessons, PAL with the highest and lowest amount of PA and intensity are presented with corresponding duration, primary bodily movement, location, subject, and academic task in Table 4. All PAL segments observed and assessed are presented in the same way in Supplementary Tables 1–3. Table 4 and the supplementary files display a large diversity in PAL delivered by the teachers in terms of PA level, PA intensity, duration, and different organizational aspects.

This study breaks new ground by being the first to observe PAL enactment and academic content and describe the corresponding PA levels when experienced teachers enact PAL in their real-world practice. The findings contribute to our understanding of how different ways of enacting PAL may contribute to the amounts of total PA and MVPA among children and adolescents in a day-to-day setting. In addition, this study provides novel perspectives into how the coherency of academic content and organization of PAL influence PA levels and intensity. Overall, the main findings displayed a large diversity in total PA levels and intensity distribution during PAL. Teachers mainly organized PAL as non-competitive group work tasks. Most of the time, higher PA intensities were generally generated through PAL facilitated outside of the classroom. Running and/or walking was, in most cases, selected as the primary movement.

The PA levels during PAL were comparable to what Morris et al. (30) and Vazou et al. (7) reported from their experimental studies. However, the results from this study are lower than what has been reported from other experimental studies and systematic reviews examining the effect of PAL on PA levels (3, 5, 6, 8). However, it is challenging to compare the PA data from the present study to other experimental studies due to the differences in study design (experimental study vs. real-world case study). Although the sample size in the present study was small, our results might suggest that when teachers enact PAL in their real-world practice, PA levels might be lower compared to researcher-led, experimental studies. On the other hand, some PAL segments observed in the present study included high amounts of total PA and MVPA, but this was evident when teachers made sense of it in a pedagogical and didactical context. The present results might be supported by recent qualitative PAL studies reporting that teachers are more concerned with learning processes and academic outcomes rather than the sole health perspective and PA levels (16–18). Moreover, evidence suggests that the desired educational purposes guide how PAL is enacted and thus the corresponding PA intensity and PA level (18, 19). This may be illustrated in Table 4 and the two examples from sixth grade. The two sessions were of equal duration, led by the same teacher and in the same subject, yet with different planned academic tasks and curricular learning outcomes. This led to different content and organization and a large difference in PA levels (1.0 min vs. 9.7 min of MVPA; Table 4). The findings of Mandelid et al. (18) resonate with the present findings that more dialogical and collaborative tasks generate different PA levels and intensity compared to tasks organized purely for repetition purposes.

The nuanced perspective of teachers on PA levels in PAL enactment reported in previous studies (16–18) and the aforementioned perspectives may also be reflected by the present teachers organizing the majority of PAL (83.7%) as non-competitive, collaborative group (>2 pupils) or pair work. Teslo et al. (17) and Schmidt et al. (31) reported that teachers and pupils embrace this way of organizing PAL because it is perceived as an important contributor to a more inclusive learning environment. In the same vein, the findings of Schmidt et al. (32) highlighted that teachers wanted to avoid creating competitive activities to ensure that all pupils were included, although some pupils often seem to have a competitive mindset regardless of how little the teachers emphasize it (31, 33). Previous studies have also reported that PAL enacted in teaching, to a larger degree than traditional classroom teaching, creates opportunities to reach social goals in school (16, 17). In a Norwegian educational context, the social perspective of PAL also adheres to the school's goal of developing and educating children with life skills to become active and engaged citizens (34, 35). Such perspectives might influence what PA levels are most suitable for PAL enactment and what PA levels can be expected in real-world contexts. As the present study indicates, the teachers' perspectives and freedom to organize PAL should be accounted for when evaluating PA levels. Hence, we argue that the results from the present study may reflect PA levels generated through PAL that might be expected when teachers make sense of enacting PAL and are thus more applicable and sustainable in a real-world context.

Although SED generally dominated PAL, approximately 10 min of total PA were generated on average. Considering that teachers generally enacted PAL 2–3 times per week, this implies 20–30 min of additional PA per week, with 10–15 min categorized as MVPA (Table 2). Although the present study includes a small sample of pupils and teachers, the results might indicate that children exposed to PAL weekly throughout 10 years in primary and secondary schools will be able to accumulate a valuable amount of PA that they might not otherwise have done. In addition, the everyday encounter with PA in school, either at higher or lower intensities, may shape positive attitudes toward PA and, therefore, be an important contributor to public health. Future studies should investigate these potential benefits in more detail. This is also interesting in relation to the WHO adjusting their recommendations in 2020 to emphasize that “every move count” (11), which implies that all PA, even at lower intensities, becomes important.

In terms of MVPA levels, the contribution from PAL in the present study was approximately 7% of the recommended 60 min of daily MVPA recommended by WHO for children and adolescents (11). This is somewhat lower compared to previous experimental studies (4–6, 8). On the other hand, some enacted PAL generated almost 30% of the recommended MVPA levels in individual pupils (Table 4). The present study, therefore, provides novel insights into not only the variety of PA intensity in PAL enacted in different teaching lessons by experienced teachers but also how much MVPA and total PA can be expected through this teaching method. In addition, PAL facilitated outdoors or inside in stairways and gyms generated more MVPA compared to PAL in the classroom. This is in line with previous studies that have reported that moving pupils outdoors during various school activities positively affects total PA and MVPA levels (36–38). From a health perspective, moving PAL out of the classroom may have a higher potential for incorporating more intensive PA in PAL and, therefore, contribute to the WHO guidelines to a greater extent (11). However, as the present results display, moving PAL outdoors for more intensive PA is conducted when teachers make sense of that with regard to the academic task and preferred learning outcome.

All primary movements observed in PAL corresponded to foundational movement skills, as defined by Hulteen et al. (29). The observed teachers organized their PAL mainly by use of familiar movement patterns, such as running (48.6%) and walking (29.7%). This corresponds with findings of movement patterns of pupils during recess in school (39). However, there needs to be more knowledge of which movement patterns are predominantly used in teacher-led PA, such as PAL and physical education. In a previous meta-analysis, the rate of participation in foundational movement skills (e.g., running, jumping, and strength exercises) was associated with higher levels of PA throughout the lifespan (40). Therefore, PAL may be an important tool to ensure that children and adolescents develop and participate in more foundational movements throughout early life and create a foundation to sustain higher PA levels throughout the lifespan.

When experienced PAL teachers enacted PAL in their real-world practice, a great coherency was observed between academic content, PAL organization, and levels and intensity of PA. Teachers enacted PAL with great emphasis on pupils working in groups within tasks without competitive instructions and with mainly running or walking as the primary movement patterns. Although SED dominated PAL, MVPA levels ranged from negligible to almost one-third of the duration. Accordingly, the intensity and levels of PA seemed to be influenced by how teachers organized PAL activities in terms of location, bodily movement patterns, academic content, and collaborative work.