Background
Moderate-to-vigorous physical activity (MVPA) is important for physical and mental health among youth and is critical for healthy development and disease prevention [
1,
2]. Despite the multitude of benefits, approximately two thirds of Canadian youth are falling short of the recommended 60 min of MVPA per day [
3‐
5]. Youth PA also tends to decrease with age [
6,
7], with large declines observed during secondary school when sedentary behaviours typically increase [
6‐
9] and the participation in physical education [
10,
11] and sports [
12,
13] typically decreases. These trends in youth PA are alarming because physical inactivity is a leading modifiable risk factor for premature death [
14‐
16]. Youth are an important target population for PA interventions because health behaviours, such as PA, continue to develop during this time [
8,
17‐
19]. Modest increases in PA can have a positive impact on health and risk of disease [
20], and school-level PA interventions can encourage these modest increases and effectively target physical inactivity among youth [
21‐
23].
School-based PA programs are effective strategies to increase PA among youth, because they can effectively target and reach youth populations while reducing common barriers to youth PA (e.g., time, transportation, skill/ability) [
24‐
26]. School-based PA programs are especially effective when they are perceived as inclusive and accessible by students [
27]. Intramurals are activities that are participated in by students within the same school, and are an example of such inclusive and accessible programs, as they generally do not require a high-level of skill or a fee to participate in [
28]. Intramurals are considered inclusive and accessible, especially compared to other school-based programs (e.g., varsity sports), which typically require a higher level of skill and involve competition against students from other schools [
28]. The positive association between participation in intramurals and PA among youth has been well-documented [
21,
29‐
31], and their impact on youth MVPA over time has been previously explored [
32,
33]. Specifically, previous studies have explored how real-world changes in intramurals affect youth MVPA over time, and although general changes in intramurals were not associated with youth MVPA over time [
33], adding a combination of individual (e.g., running) and team (e.g., soccer) intramurals was positively associated with female MVPA [
32]. Our earlier evidence suggested that adding a variety of intramurals had a positive effect on female MVPA regardless of intramural participation, highlighting the positive and indirect relationship between changes in intramurals and MVPA [
32]. In addition to individual and team intramurals, intramurals are further categorized by gender-specific (e.g., female-only, male-only) and co-ed, which may have differential effects on the PA of female and male youth. Limited research has been done to examine how gender-specific and co-ed intramurals associate with PA; however, previous research suggests that gender-specific intramurals may be an important factor for intramural participation, particularly among female students. For example, a previous study found that female students attending schools with female-only intramurals were more likely to participate in intramurals compared to females attending schools without these female-only intramurals, and no such association was observed for males [
34]. Female youth consistently achieve less PA compared to their male counterparts [
3‐
5], suggesting that gender-specific sports may be an important opportunity for female PA.
There is limited research available on the impact of gender-specific and co-ed intramurals on youth MVPA over time. Given the previous positive relationship observed between adding individual and team intramurals and female MVPA [
32], a practical next step would be to examine how gender-specific and co-ed intramurals affect youth MVPA. Schools continue to make changes to gender-specific and co-ed intramurals each year, and these changes are considered a natural experiment because they are not under control of the researchers [
35]. These changes in school-level intramurals create the unique opportunity to evaluate a natural experiment and generate practice-based evidence [
36]. Therefore, the objective of this study is to use a natural experimental study design to evaluate how changes in school-based gender-specific and co-ed intramurals are associated with female and male youth MVPA over time.
Results
School-level descriptive characteristics
Statistics describing the characteristics of the school-level sample are presented in Table
1. Specific to the changes in gender-specific and co-ed intramurals from Y5 to Y6, 27 schools primarily added co-ed intramurals, 8 added gender-specific intramurals, 3 schools made no net change to intramurals, and 17 school removed intramurals. Five schools reported adding PA programs from Y5 to Y6. In Y5, the mean school neighbourhood median income was $69,804 (SD = $15,404) and the mean school size was 669 students (SD = 288). An average of 5.4 (SD = 4.1) intramural programs were offered at the schools in Y5.
Table 1
Descriptive Statistics for School-Level Characteristics for the sample (n = 55) from Year 5 and 6 (2016–2017) of the COMPASS Study
Changes in Types of Intramurals from Y5 to Y6 | Primarily Added Co-ed Intramurals | 27 | 49.1 |
Added Gender-Specific Intramurals | 8 | 14.6 |
No Net Change in Intramurals | 3 | 5.5 |
Removed Intramurals (Reference) | 17 | 30.9 |
Changes in Other PA Programs from Y5 to Y6 | No Change (Ref) | 50 | 90.9 |
Added Programs | 5 | 9.1 |
Removed Programs | 0 | 0 |
Variable | Mean | SD |
School Neighbourhood Median Income in Y5 | $69, 804 | $15,404 Min: $31,763 Max: $107, 702 |
School Size In Y5 | 669 | 288 Min: 136 Max: 1550 |
Number of Intramurals Offered in Y5 | 5.4 | 4.1 Min: 0 Max: 14 |
Student-level descriptive characteristics
Statistics describing the baseline characteristics and the time-varying characteristics of the student-level sample are presented in Table
2 and Table
3. As shown in Table
2, 54% (
n = 2402) of the sample were female, 73% (
n = 3210) were white and $1–$20 was most frequently (43%,
n = 1875) reported amount of weekly spending money. Presented in Table
3, intramural participation among female students was 38% in Y5, 36% in Y6 and 33% in Y7 and 39% in Y5, 37% in Y6 and 36% in Y7 among male students. Average daily MVPA decreased among female and male students over time, with females reporting 105 min (SD = 66) in Y5, 97 min (SD = 64) in Y6 and 89 min (SD = 61) in Y7 and males reporting an average of 117 min (SD = 68) in Y5, 109 min (SD = 68) in Y6 and 102 min (SD = 65) in Y7.
Table 2
Descriptive Statistics for Baseline Student-Level Characteristics for the sample (n = 4417) from Year 5 (2016–2017) of the COMPASS study
Grade | Grade 9 (Ref) | 2434 (55.1) | 1335 (55.6) | 1099 (54.5) | 1 | 1.431 | 0.232 |
Grade 10 | 1983 (44.9) | 1067 (44.4) | 916 (45.5) |
Ethnicity | White (Ref) | 3210 (72.7) | 1744 (72.6) | 1466 (72.8) | 1 | 0.036 | 0.849 |
Other | 1207 (27.3) | 658 (27.4) | 549 (27.2) |
Weekly Spending Money | Zero (Ref) | 1130 (25.6) | 541 (22.5) | 589 (29.2) | 3 | 107.400 | <.0001 |
$1–$20 | 1875 (42.5) | 1062 (44.2) | 813 (40.3) |
$21–$100 | 1065 (24.1) | 628 (26.1) | 437 (21.7) |
$100+ | 347 (7.9) | 171 (7.1) | 176 (8.7) |
Table 3
Descriptive Statistics for Time-Varying Student-Level Characteristics for the sample (n = 4417) from Year 5 (2016–2017), Y6 (2017–2018) and Y7 (2018–2019) of the COMPASS study
Intramurals | No (Ref) | 2733 (61.9) | 2813 (63.7) | 2903 (65.7) | 1494 (62.2) | 1542 (64.2) | 1616 (67.3) | 1239 (61.5) | 1271 (63.1) | 1287 (63.9) |
Yes | 1684 (38.1) | 1604 (36.3) | 1514 (34.3) | 908 (37.8) | 860 (35.8) | 786 (32.7) | 776 (38.5) | 744 (36.9) | 728 (36.1) |
Varsity | No (Ref) | 2568 (58.1) | 2529 (57.3) | 2688 (60.9) | 1464 (60.9) | 1447 (60.2) | 1558 (64.9) | 1104 (54.8) | 1082 (53.7) | 1130 (56.1) |
Yes | 1849 (41.9) | 1888 (42.7) | 1729 (39.1) | 938 (39.1) | 955 (39.8) | 844 (35.1) | 911 (45.2) | 933 (46.3) | 885 (43.9) |
Community | No (Ref) | 2109 (47.7) | 2394 (54.2) | 2781 (63.0) | 1218 (50.7) | 1377 (57.3) | 1599 (66.6) | 891 (44.2) | 1017 (50.5) | 1182 (58.7) |
Yes | 2308 (52.3) | 2023 (45.8) | 1636 (37.0) | 1184 (49.3) | 1025 (42.7) | 803 (33.4) | 1124 (55.8) | 998 (49.5) | 833 (41.3) |
Variable | Mean (SD) | Mean (SD) | Mean (SD) | Mean (SD) | Mean (SD) | Mean (SD) | Mean (SD) | Mean (SD) | Mean (SD) |
MVPA (min/day)* | 110 (67) n = 4417 | 102 (66) n = 4414 | 95 (64) n = 4375 | 105 (66) n = 2402 | 97 (64) n = 2400 | 89 (61) n = 2380 | 117 (68) n = 2015 | 109 (68) n = 2014 | 102 (65) n = 1995 |
Results from linear mixed models
The ICC was used to estimate the variability in MVPA among female and male students that were attributed to between-school differences. Between-school differences accounted for 1.91% of the variability in female MVPA and 2.09% in male MVPA, which suggests that the characteristics of the school a female or male student attends, are modestly associated with their MVPA. Results from the linear mixed models are presented in Table
4. Female and male students in grade 10 at baseline accumulated significantly less average MVPA minutes per day compared to those in grade 9 (females:
\( \hat{\beta}= \)-8.428,
p < 0.0001, males:
\( \hat{\beta}= \)-7.298,
p = 0.001). MVPA decreased over time for both females and males, although this was only significant for female students (females:
\( \hat{\beta}=-7.253 \),
p = 0.004, males
\( \hat{\beta}= \)-1.100,
p = 0.692). Sport participation was positively associated with female and male MVPA, as students participating in school-based intramurals (female:
\( \hat{\beta}= \) 4.998,
p = 0.003, male:
\( \hat{\beta}= \) 9.728,
p < 0.0001), school-based varsity sports (female:
\( \hat{\beta}= \) 16.161, p < 0.0001, male:
\( \hat{\beta}= \) 18.003, p < 0.0001) and community sports (female:
\( \hat{\beta}= \) 26.084, p < 0.0001, male:
\( \hat{\beta}= \) 20.310, p < 0.0001) achieved significantly more average MVPA minutes per day, all compared to those who reported no participation.
Table 4
Linear Mixed Models examining the association between changes in intramural programming in Y6 on MVPA in Y6 and Y7 of the COMPASS Study stratified by gender
Effect of Intramural Change on MVPA in Y6 | Removed Intramurals (Reference) | – | | – | – | – | – |
Primarily Added Co-ed Intramurals | 4.695 | −0.699-10.089 | 0.088 | −1.163 | −7.32-4.998 | 0.711 |
Added Gender-Specific Intramurals | 5.098 | −2.382-12.578 | 0.182 | −4.703 | −13.194-3.787 | 0.278 |
No Net Change in Intramurals | 2.236 | −4.060-8.534 | 0.486 | 5.148 | −1.780-12.075 | 0.145 |
Effect of Intramural Change on MVPA in Y7 | Removed Intramurals (Reference) | – | – | – | – | – | – |
Primarily Added Co-ed Intramurals | 1.749 | −3.66-7.159 | 0.526 | 0.411 | −5.764-6.587 | 0.896 |
Added Gender-Specific Intramurals | 7.507 | −0.0126-15.027 | 0.050 | −3.764 | −12.276-4.748 | 0.692 |
No Net Change in Intramurals | −1.502 | −12.079-9.075 | 0.781 | 8.747 | −2.818-20.312 | 0.138 |
Grade | Grade 9 (Ref) | – | – | – | – | – | – |
Grade 10 | −8.428 | −12.131--4.724 | <.0001 | −7.298 | −11.421--3.175 | <.0001 |
Year | −7.253 | −12.391--2.348 | 0.004 | −1.100 | −6.554-4.353 | 0.692 |
Intramural Sport Participation | No (Ref) | – | – | – | – | – | – |
Yes | 4.998 | 1.7647–8.2318 | 0.003 | 9.728 | 6.051–13.406 | <.0001 |
Varsity Sport Participation | No (Ref) | – | | – | | | – |
Yes | 16.161 | 12.506–19.815 | <.0001 | 18.003 | 13.902–22.104 | <.0001 |
Community Sport Participation | No (Ref) | – | | – | | | – |
Yes | 26.084 | 22.784–29.384 | <.0001 | 20.310 | 16.520–24.101 | <.0001 |
The associations between changes in gender-specific and co-ed intramurals and MVPA were non-significant for both female and male youth, regardless of whether students reported participating in these programs. Specifically, primarily adding co-ed intramurals, adding gender-specific intramurals and making no net changes to intramurals in Y6 were all positively, but non-significantly associated with female MVPA in Y6. If these changes were to continue into Y7, primarily adding co-ed intramurals and gender-specific intramurals were both positively, but non-significantly associated with female MVPA one year later, into Y7. This significance of the association between maintaining the addition of gender-specific intramurals on female MVPA in Y7 was on par with significance level of α = 0.05; and hence was inconclusive. If schools that added gender-specific intramurals in Y6 maintained these changes into Y7, female students accumulated an average of 7.507 more daily minutes of MVPA compared to female students attending schools that removed intramurals. Lastly, if schools maintained no net changes from Y6 into Y7, this was negatively and non-significantly associated with female MVPA in Y7.
Primarily adding co-ed intramurals and gender specific intramurals in Y6 was negatively and non-significantly associated with male MVPA in Y6. If these changes were to continue into Y7, primarily adding co-ed intramurals was positively but non-significantly associated with male MVPA into Y7, while adding gender-specific intramurals was negatively and non-significantly associated with male MVPA in Y7. No net changes in intramurals in Y6 was positively and non-significantly associated with male MVPA in Y6. If these changes were maintained in Y7, the direction of this association was consistent, as no net changes was positively and non-significantly associated with male MVPA in Y7 as well.
Discussion
To our knowledge, this was the first study to evaluate how changes in gender-specific and co-ed intramurals were associated with MVPA over time. This study builds on previous research [
32,
33] using COMPASS data which found that although general changes to intramurals were unrelated to youth MVPA, adding a combination of individual and team intramurals had a positive impact on female MVPA. Considering that intramurals are also divided into gender-specific and co-ed intramurals, exploring the association between these specific intramurals and MVPA among youth was a logical progression of this previous research. This association was examined using a large, linked longitudinal school- and student-level dataset, and employed an innovative methodology that allowed for the examination of the effect of changes in gender-specific and co-ed intramurals on MVPA in Y6 and into Y7, under the assumption that these changes were continued from Y6. The results of this study suggest that youth MVPA generally decreases over time, and although no statistically significant associations were observed, the effect of gender-specific intramurals on female MVPA may be important, and should be further explored. Future research should explore the associations between gender-specific intramurals and youth MVPA over time using a larger school sample to ensure adequate power at the school-level.
As expected, [
3,
4,
45,
46] average daily MVPA decreased among female and male students over time, and female and male students in grade 10 at baseline achieved significantly less daily MVPA minutes per day compared to youth in grade 9 at baseline. The decreasing trends in MVPA over time among youth may be attributed to many social, behavioural and environmental factors typically observed during this time which may include perceived lack of time [
47], decreases in sport participation [
12,
13], and increased screen time and sedentary behaviour [
6‐
9]. Although MVPA declined over time for both females and males, this association was only significant for females, which may be explained by the greater decrease in MVPA over time typically observed in females compared to males [
48,
49]. Sport participation was positively associated with MVPA among female and male youth. Other research supports these findings, as intramural [
21,
30,
31], varsity [
30,
31] and community [
30,
50‐
52] sport participation all positively associate with MVPA among female and male youth. These school- and community-based sports provide opportunities for PA, which is an important correlate of youth MVPA [
26,
52,
53].
Primarily adding co-ed intramurals and no net change in intramurals were not associated with female or male MVPA in Y6 or Y7. Although no research was found directly on intramural change, other research on intramurals supports this finding, as the availability of intramurals was not directly associated with student MVPA [
23,
29]. Although the environmental context can influence youth MVPA, intrapersonal and interpersonal characteristics may be more important predictors of MVPA [
54], which may help explain these nonsignificant findings. For example, intrapersonal factors such as self-efficacy and enjoyment, and interpersonal factors such as peer support for PA are all positively associated with youth MVPA [
54‐
57], and aspects of school-PA environment, such as the availability of school programs [
54], may not be as important for youth MVPA. Therefore, changes in the school environment, such as adding co-ed intramurals, or making no net changes to intramurals, may not be sufficient approaches to increasing MVPA among youth. More comprehensive strategies to address the physical inactivity among youth are warranted. For example, PA programs that include a combination of changes to the school environment (e.g., school curriculum, school-based policies), community engagement and parental involvement have proven effective in improving youth PA [
24,
58,
59] and warrant further investigation and evaluation.
There were no significant associations between adding gender-specific intramurals and MVPA among female or male students. However, there may not have been adequate power at the school-level to detect a significant association, as only 8 schools reported adding gender-specific intramurals in our sample. Although this association may be underpowered at the school-level, it is important to note that adding gender-specific intramurals was positively associated with female MVPA in Y7, and the
p-value of this association warrants further exploration using a larger school-level sample. Past research has suggested that gender-specific intramurals are more important for female youth participation, compared to males [
34]. Females may face more barriers to sport participation and PA compared to males, and these barriers range from intrapersonal to environmental factors, as described by the social-ecological model [
60,
61]. More specifically, females may face intrapersonal barriers (e.g., low self-efficacy), interpersonal barriers (e.g., time-restraints and lack of social support from peers), and environmental barriers (e.g., lack of choice and limited female-only opportunities in PA programs) [
61]. To address these barriers, strategies to increase self-efficacy, provide accessible PA programs and create a supportive PA environment are warranted [
61]. Gender-specific intramurals may provide females with this environment by offering supportive and accessible opportunities to be physically active, and reducing some of these barriers to PA. For example, female-only intramurals may increase confidence and self-efficacy by providing a safe space to participate in PA, that is free of intimidation or excessive competition that may be present in a co-ed environment [
21,
61]. These female-only programs may also address time-restraints by providing access to PA during school-time and may promote positive interactions with peers and encourage peer support for PA [
54‐
57]. Finally, gender-specific intramurals address programming barriers, by providing a variety of female-only opportunities to be physically active [
61].
Strengths and limitations
This research comprehensively examined how changes in gender-specific and co-ed intramurals were associated with youth MVPA over time and addressed an important gap in the literature to expand on our understanding of how changes to school-level intramurals affect youth PA outcomes. This study utilized a large linked sample of longitudinal student- and school-level data, and employed a robust evaluation of a natural experiment to generate practice-based evidence on school intramurals. Additionally, this study utilized a novel approach to program evaluation through the use of indicator variables, and future research may consider using such methods to evaluate programs and generate timely public health evidence.
It is also important to note the limitations of this study. Firstly, the generalizability of these results may be limited, as COMPASS uses convenience sampling to recruit schools. However, the COMPASS study has a large sample size and employs an active-information, passive-consent procedure to promote participation and honest responses from students [
62]. Additionally, this procedure may produce more robust results by limiting self-selection and response biases [
37]. Secondly, because schools made many changes to their gender-specific and co-ed intramurals, the intervention groups may have been diluted. For example, the intervention groups consisted of schools that: (i) “primarily” added co-ed intramurals, (ii) “primarily” added gender-specific and (iii) no net changes to intramurals, as opposed to schools that: (i) “only” added co-ed intramurals, (ii) “only” added gender-specific intramurals and (iii) no changes to intramurals. These diluted intervention groups may have made associations difficult to detect, which highlights the complexity of evaluating PA programs using a natural experiment. Thirdly, this study may have been under-powered at the school-level, possibly limiting the ability to detect associations between changes in gender-specific intramurals on youth MVPA over time. However, this study provides insight into the potential role of gender-specific and co-ed intramurals on youth MVPA, and future research should explore these associations using a larger school-level sample to ensure adequate power.
Conclusions
This study found that intramural and varsity sports are important school-based opportunities for youth PA, as participation in these sports were positively associated with MVPA. To encourage sport participation and PA among students, schools should continue to offer a variety of intramural and varsity sports. Changes in gender-specific and co-ed intramurals were not associated with female or male MVPA over time. Changes in the school environment, such as adding gender-specific and co-ed intramurals may not be sufficient strategies to increase PA among youth, although further research should explore the effect of gender-specific intramurals on youth PA, as this study may have been underpowered at the school-level. Gender-specific intramurals may promote a supportive PA environment by fostering self-efficacy, enjoyment and peer support, especially among females. These intramurals may be an important component of more comprehensive strategies to increase youth PA.
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