Human motivation is a complex and multifaceted phenomenon resulting from the interaction of intrinsic and extrinsic factors, with social factors playing a pivotal role (1). Achievement motivation theory (2) analyses how various needs, such as the desire for achievement, power and affiliation, influence individual motivation in different contexts. In this context, Nicholls and Maehr (2) identified social approval as one of the primary social objectives within the three broad, universal motivations. This perspective has prompted research providing empirical evidence of the influence of social approval in the sporting context (3, 4).

Motivation has been identified as a key factor in sport, as it directly affects athletes' performance, persistence and satisfaction (5). Motivation can manifest both intrinsically, on the basis of enjoyment, interest and self-improvement, and extrinsically, on the basis of external rewards and recognition (6). In this context, social motivation is particularly relevant, as the need for approval and recognition from peers, coaches or spectators can strengthen commitment to sport and encourage group cohesion in team sports (7–9). Moreover, it can also impact self-image and performance in individual disciplines.

Several instruments have been developed to assess motivation in sports, primarily on the basis of theoretical frameworks such as self-determination theory (10) and achievement goal theory (2). Popular questionnaires such as the Sport Motivation Scale (SMS) (11) and the Perception Of Success Questionnaire (POSQ) (12) have enabled the exploration of intrinsic and extrinsic motivational factors, as well as task or ego orientation. However, social motivation has received less attention in terms of measurement. Instruments such as the Social Motivation in Sport Scale (SMOSS) (13) address this dimension more directly and provide a useful means of investigating the impact of social factors on participation in sport. This is particularly relevant in educational contexts, where social factors such as affiliation, status and recognition can be important motivators of participation and engagement in both structured sports and physical education (PE) (14, 15).

Although the SMOSS was introduced two decades ago, it remains the only instrument available for measuring social motivational orientations in sports. While some studies have adapted the tool for use in PE (16, 17), to our knowledge, only three studies (18–20) have evaluated its psychometric properties in adolescents. Furthermore, to date, the SMOSS has only been translated and adapted into Portuguese (18), and there is still no validated version for the Spanish population. However, given that our target population is children aged 6–12, no adaptations for this age group have yet been developed, representing a significant gap in the literature. It is therefore essential to adapt the original instrument rather than apply it directly, considering sociocultural and contextual differences (21, 22), as well as the cognitive and linguistic variations (23) between children and adolescents/adults. This will enable a more accurate evaluation of the social motivations that influence children's participation in sports.

Therefore, the main objective of the present study was to validate a Spanish version of the SMOSS adapted specifically for use with Spanish schoolchildren aged 6–12 years, resulting in the SMOSS for children (SMOSS-C). This will allow for a deeper understanding of, and evaluation of, the social factors influencing participation in PE classes and will facilitate the design of intervention programs that effectively address the difficulties encountered in this area.

To evaluate the clarity and functional understanding of the adapted items, individual cognitive interviews were conducted with a pilot sample of schoolchildren (n = 17). Cognitive interviews were conducted with 17 children (4 in 2nd grade, 4 in 3rd, 3 in 4th, 3 in 5th, and 3 in 6th), following WHO guideline steps and expert panel review; 3 of the initially invited 20 children missed one of the sessions. These interviews focused on analyzing both literal and contextual comprehension. Understanding was also evaluated through an interview process aligned with best practices to ensure child-friendly instruments (25).

In the second phase, the psychometric properties of the SMOSS-C were analyzed. This included a confirmatory factor analysis (CFA) to assess construct validity. Additionally, a test‒retest reliability study was carried out with a subsample of children who completed the questionnaire twice, with a two-week interval, to assess the temporal stability of the responses.

This rigorous, phased approach ensured that the SMOSS-C was not only linguistically and culturally appropriate for Spanish children but also psychometrically sound in terms of content validity, functional comprehension, and reliability.

The final version of the adapted instrument is available in Supplementary Material S1.

This study aimed to adapt the SMOSS, which was originally designed for adolescents and young adults, for its use with Spanish children aged 6–12 years (SMOSS-C). The study also analyzed the psychometric properties of the adapted instrument, with a focus on its factor structure, internal consistency and temporal stability. Our findings support the validity and reliability of the SMOSS-C for its use with this age group. The CFA showed a good fit between the model and the data, suggesting that the questionnaire's theoretical structure is appropriate for this age group. Reliability analyses revealed that the instrument has acceptable to excellent internal consistency for most items, as well as high temporal stability for the total score. However, items 6 and 15 were identified as having low consistency and test‒retest reliability values, suggesting that they may not function adequately in this population and may require revision and even removal in future versions of the questionnaire. Overall, these findings indicate that the SMOSS-C is a valuable and promising instrument for evaluating the social motivational orientations of school-aged children, establishing a robust foundation for its application in educational and research settings.

The CFA of the SMOSS-C revealed that the theoretical model fit the empirical data adequately, thus supporting the structural validity of the questionnaire in the child population. Specifically, the CMIN/df value (1.667) was within the range considered to indicate an excellent fit (<2), and the CFI (.943) and TLI (.926) indices far exceeded the threshold of .90, approaching the (35) and Bentler (35) criterion of excellence (.95). Additionally, the RMSEA value (.072) remained within the acceptable range (<0.08), indicating a reasonable approximation error. While the chi-square test was statistically significant (p < .001), this is a common occurrence in moderate or large samples and should not be interpreted as evidence of a poor fit in isolation (34). Therefore, taken together, the obtained indices suggest that the instrument's original factor structure remains adequate after its linguistic and conceptual adaptation for use with Spanish schoolchildren. These results are particularly relevant given that the SMOSS-C was applied to children aged 6–12, who are at a stage of development with specific cognitive and linguistic characteristics (37). The adequacy of the factorial model indicates that children consistently understand and respond to the various items assessing social motivational orientations in a sporting context. This further supports the value of the questionnaire as a valid tool for use in primary education.

Regarding the internal consistency outcomes of the SMOSS-C, the total score showed excellent consistency (Cronbach's α = .891), indicating high homogeneity among the items and their ability to consistently measure the construct of social motivational orientation in sport, on the basis of achievement motivation theory (2). At the item level, most items had α values ranging from acceptable to good, which reinforced the internal consistency of the instrument. However, it is important to note that items 6 (Cronbach's Cronbach's α = .531) and 15 (Cronbach's α = .466) showed poor and unacceptable levels of consistency, respectively. These results suggest that these items may not adequately capture the construct in this child population, possibly because of factors such as language complexity, ambiguous wording or difficulty interpreting them (38). Reformulating these problematic items could improve the instrument's overall reliability, particularly for its use in longitudinal studies. Overall, the internal consistency of the SMOSS-C is solid, although there is room for improvement in certain items.

The test‒retest reliability assessment of the SMOSS-C revealed positive results in terms of the instrument's temporal stability. The total questionnaire score obtained an ICC of .891, indicating an excellent degree of agreement between measurements taken 15 days apart. This finding supports the robustness of the instrument for reliably assessing social motivational orientations in children's sports contexts. At the item level, most items had ICC values ranging from moderate to nearly perfect, suggesting that the children responded consistently over time. However, as in the internal consistency analysis, specific problems were detected in items 6 (ICC = .363) and 15 (ICC = .305), which showed low levels of stability and achieved only “fair” agreement according to the criteria of Landis and Koch (31). This reinforces the need to revise these items, as their low stability could be due to variable interpretations or comprehension difficulties on the part of the children's group. These results are consistent with those of most motivation questionnaires for children, which demonstrate good or excellent test‒retest reliability, with ICCs typically ranging from moderate to high (39–41). However, some subscales or items tend to demonstrate lower reliability (42, 43), and cultural adaptation, the use of abstract language, or social factors may affect the outcomes (44). Similarly, research on physical literacy questionnaires, such as the CAPL-2 (45), has identified issues with the stability of items when applied to younger groups. This suggests that this is a common challenge in the field of child psychometric assessment.

Similarly, absolute error analyses (SEM and MDC) indicated that the measurement error was low in the total score (%SEM = 7.0; %MDC = 19.5), further supporting the overall accuracy of the instrument. However, some individual items presented high %SEM and %MDC values (e.g., item 5 with an %SEM of 42.9), which could reflect greater variability in children's responses and suggest that some items may be more sensitive to contextual or interpretation factors (46). Nevertheless, the minor deviations found in this study are relatively common and can likely be attributed to the linguistic and developmental characteristics typical of younger populations (47).

Analysis of the correlations between each item and the total SMOSS-C score produced positive results, which are consistent with those of the other reliability tests and previous validations of the instrument (13, 18). All the items showed significant correlations with the total questionnaire score (p < .01), supporting the idea that each item contributes significantly to measuring the overall construct. The Spearman's ρ coefficients ranged from 0.337 to 0.777, indicating a moderate to strong relationship between the individual items and the overall score. However, item 15 was identified once again as having the lowest correlation with the total score (Spearman's ρ = .337). This suggests that this item may measure aspects that generate ambiguous interpretations by children (43). This observation coincides with the issues identified in internal consistency and ICC analyses, emphasizing the need for revision.

A critical strength of this study was the inclusion of McDonald's omega (ω) alongside Cronbach's alpha (α). By reporting omega values of .892 (test) and .886 (retest), we addressed the inherent limitations of alpha regarding the assumption of tau-equivalence (a constraint frequently violated in developmental research where item-factor loadings can vary). These high coefficients indicate that the items represent the underlying construct consistently, ensuring that the total scores are reliable for assessing the social motivational orientations in sport in children. Furthermore, the stability of these coefficients across the two measurement points, coupled with the Bland-Altman plot analysis, provides a rigorous validation of the scale's reliability. Unlike traditional correlation coefficients, the Bland-Altman approach confirmed a mean bias near zero with tight limits of agreement, demonstrating that the SMOSS-C is not significantly affected by systematic measurement errors or learning effects during retesting. While some items exhibited ceiling effects (particularly Item 15) the overall high comprehensibility scores across all age groups (6–12 years) suggest that the instrument is conceptually and linguistically appropriate for its target population. The combination of high internal consistency and strong temporal agreement positions the SMOSS-C as a reliable tool for both clinical and educational settings.

One of the main strengths of the SMOSS-C is its rigorous linguistic and cultural adaptation process. This approach involves direct and reverse translation in accordance with international recommendations, as well as adapting the content to suit the cognitive, linguistic, and socioemotional levels of children aged 6–12. Another notable strength of the SMOSS-C is its applicability in real-life educational and sporting contexts. Primary education plays a crucial role in developing attitudes, values and motivations toward PA. Having a valid and reliable tool enables the diagnosis of motivational profiles and the guidance of more effective pedagogical interventions adapted to students' needs. In this sense, the SMOSS-C can be used by PE teachers, coaches, school counsellors, and sports professionals to (1) identify the social factors that influence children's motivation to play sports (e.g., group acceptance, the desire for recognition and social pressure); (2) design motivational strategies that are tailored to the profile of their students or athletes; and (3) evaluate the impact of intervention programs on social motivation in school or extracurricular sporting contexts. The brevity and accessible format of the questionnaire make it a practical tool for use with young children, as it minimizes their risk of becoming fatigued or losing attention while completing it.

Importantly, this study aligns with a recent article on the development of the first assessment model for physical literacy in Spain: the Spanish Physical Literacy Assessment for Children (SPLA-C) (48). In this Delphi study, national experts concluded that this scale should form part of the 'social interaction and barriers to physical activity practice' component of the new PL assessment model in Spain. As part of the SPLA-C model, the SMOSS-C enables schools and policymakers to monitor students' social development in relation to the PL. This information can be used to design more holistic PE programs that address not only physical skills but also students' social motivation to participate in sports.

While the results obtained support the validity and reliability of the SMOSS-C for use with children, it is important to recognize the following limitations, which should be considered when interpreting the findings and guiding future research.

First, possible differences in the instrument's structure or reliability according to gender, level of sporting experience or specific age were not explored. A limitation of the present study is that subgroup analyses examining measurement equivalence or invariance across gender, age, and sport experience levels were not conducted. Such analyses are important, particularly given children's age-dependent comprehension, which could influence item interpretation and scale performance. Future research will aim to perform configural, metric, and scalar invariance tests, especially across gender and age groups, to ensure the instrument functions equivalently across subpopulations. Given the current sample size (n = 128), we acknowledge that statistical power may have been insufficient to support these analyses, which should be addressed in larger-scale studies.

Second, the use of a self-reported format poses an inherent challenge when working with young children, given that their ability to self-reflect or interpret abstract statements can vary considerably. Although cognitive interviews were conducted in the pilot phase, comprehension problems were evident in some items (such as items 6 and 15), suggesting that, while the linguistic adaptation was generally adequate, a more focused review of these elements could be beneficial. Therefore, future studies should conduct a more in-depth qualitative analysis of problematic items through interviews or focus groups with children, with the aim of improving their wording and comprehension. Moreover, children's responses may be influenced by social desirability, which we did not control for in this study. Similarly, future research could involve developing illustrated versions or versions supported by visual elements to facilitate use with younger children or those with reading comprehension difficulties. Also, Future studies could apply IRT/Rasch analyses to examine item difficulty and discrimination across age levels.

Finally, the cross-sectional nature of the study is a limitation, inviting future longitudinal studies to explore the sensitivity of the SMOSS-C to educational interventions or motivation programs and evaluate its ability to detect significant changes in motivational orientations over time.

This study made it possible to linguistically and culturally adapt the SMOSS for use with Spanish children aged 6–12 years. The resulting children's version is known as the SMOSS-C. Analyses show that the adapted version has a valid factor structure, as well as adequate levels of internal consistency and temporal reliability for most items and the overall questionnaire score. Although two items (i.6 and i.15) were identified as being less reliable and more difficult to understand, the overall body of psychometric evidence supports the use of the SMOSS-C as a reliable and useful tool for assessing social motivational orientations in sports among school-aged children. Using the SMOSS-C can improve our understanding of the social factors influencing children's motivation for PA and help us design more effective pedagogical strategies in education and sport. The SMOSS-C is an important step toward providing assessment tools that are adapted to the reality and needs of children's educational contexts. It promotes more motivating, inclusive, and meaningful physical and sporting practices from an early stage of development. The SMOSS-C is part of the social domain of the SPLA-C, the first model for the assessment of PL in Spain.