Bidirectional relationships of physical activity and gross motor skills before and after summer break:Application of a cross-lagged panel model

Background:Gross motor skills are postulated to have a bidirectional relationship with physical activity(PA);however,no study has tested this relationship before and after a summer break.The purpose of this study was to examine the bidirectional relationships between school PA and gross motor skills in children before and after a summer break.Methods:Participants were a sample of 440 children recruited from 3 low-income schools(age=8.9±1.2 years,mean±SD).PA was assessed as average school-day step counts using Yamax DigiWalker pedometers(Yamasa Tokei Keiki,Tokyo,Japan)worn for 5 consecutive school days.Gross motor skills were assessed using the Test for Gross Motor Development,3 rd edition.Data were collected at 2 timepoints:at the end of spring semester(T1)and at the beginning of the subsequent fall semester(T2).An age-and body mass index-adjusted cross-lagged model was employed to relate T1 school step counts with T2 gross motor skills and T1 gross motor skills with T2 school step counts.Results:T1 gross motor skills significantly predicted T2 school step counts(β=0.24,95%confidence interval(95%CI):0.08-0.40,p=0.003);however,Tl school step counts did not predict T2 gross motor skills(β=0.04,95%CI:-0.06 to 0.14,p=0.445).The model explained 35.4%and 15.9%of the variances of T2 gross motor skills and T2 school step counts,respectively.Additional analyses indicated that these relationships were driven primarily by ball skills.Conclusion:The relationship between gross motor skills and school PA was not bidirectional;however,higher gross motor skills,specifically ball skills,predicted higher school PA after a 3-month summer break.

Effect of the Resistance Exercise on Elementary School Students’Physical Fitness

Background Physical activity programs using components of resistance have the potential to improve health in school chil-dren.The purpose of this study was to examine the effect of a school-based resistance exercise program on physical fitness in elementary school students.Methods The sample was 256 children(mean age=8.3±2.5 years;119 girls)from kindergarten to 5th grade.Participants performed a 10-min resistance exercise 2-3 times in each school day.Physical fitness outcomes were assessed using President’s Physical Fitness Challenge test.Measures were collected at baseline and at a 6-month post-test time point.A 2×2 doubly MANOVA was employed to examine the effect of sex and time.Results The multivariate model was statistically significant with a main time effect(Wilks’λ=0.19,F=290.9,P<0.001).Follow-univariate tests found significant differences between time-points on flex arm hang(P=0.033),shuttle run(P<0.001),and 1-mile run/walk times(P<0.001).Conclusions A 6-month resistance exercise program improved upper body strength and cardiorespiratory endurance in elementary school aged children.The use of resistance exercise intervention during school day can be effectively used to promote physical fitness and ultimately improve the health of children.