Purpose:Given the fact that an important health objective of Healthy People 2010 is to promote students' active participation in physical education classes by at least 50% of the class time (USDHHS, 2000), physical education programs represent an important avenue to promote school children's moderate-to-vigorous physical activity levels (MVPA; Simons-Morton et al., 1990). It has been evident that students differ in their MVPA in physical education classes across different gender and grade (e.g., Kulinna et al., 2003; Vincent & Pangrazi, 2002). Few studies have been conducted to examine the gender and grade differences in accelerometer-based MVPA within middle school students. The purpose of this study, therefore, was to determine if students' accelerometer-based MVPA differed as a function of gender and grade
Methods:The participants were 147 sixth-to-eighth graders (75 boys, 72 girls; Mage = 12.44 years ±.99) at a public school in the U.S. During the data collection period, all the participants engaged in the catchball in physical education, and their physical activity levels were measured by Actical accelerometer (Mini-Mitter Co., Inc., Bend, OR). The outcome variables were the percentage of time in MVPA and average counts/min. in MVPA.
Analysis/Results:Descriptive analyses revealed that the participants were physically active in their classes (i.e., M% = 63.22 ± 13.37, Mcounts = 4762.89 ± 965.92). A 2x3 (gender x grade) MANOVA yielded a significant interaction effect (Wilks' Lambda = .90, F (4, 280) = 3.80, p < .01, ƒÅ2 = .05, and a grade effect (Wilks' Lambda = .82, F (4, 280) = 7.49, p < .01, ƒÅ2 = .10. Accordingly, further analyses were conducted by splitting the gender. Follow-up F test for boys indicated that sixth graders spent significantly higher percentage of time in MVPA than seventh and eighth graders, F (2, 72) = 13.99, p < .01, ƒÅ2 = .28. Follow-up F test for girls indicated that seventh graders displayed significantly lower percentage of time in MVPA than sixth and eighth graders, F (2, 69) = 8.16, p < .01, ƒÅ2 = .19. No further differences were found with average counts/min. in MVPA across both genders.
Conclusions:The results echo the recommendations indicating that 50% of the physical education time should involve MVPA. Our data suggested that younger boys spent higher percentage of time in MVPA, whereas seventh grade girls were not as active as other grades. The findings provide new empirical evidence for all middle school grade levels in this area of inquiry.