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Objective To examine children and adolescents physical activity level and its influencing factors based on the theory of planned behavior (TPB).Methods A total of 353 students aged 8-15 were chosen as samples.Accelerometers were used to measure the moderate-to-vigorous physical activity (MVPA) time and a TPB scale was used to measure the TPB constructs.Results ①Research results showed that only 5.3％ of the participating children and adolescents reached the recommended 60 miu MVPA each day.②There were significant gender differences in the attitude (t=1.360,P＜0.0 l),MVPA intention(t=2.076,P＜0.01) and MVPA time (t=2.076,P＜0.05) of children and adolescents.However,there was no significant differences in their subjective norms and perceived behavioral control (P＞ 0.05).Significant grade differences were also observed for attitude (F (5.352) =2.627,P＜ 0.05),MVPA intention (F(5.352)=2.890,P＜0.05) and MVPA time (F(5.352) =6.156,P＜0.01).③The regression results showed that MVPA intention (β=0.130,P＜0.01) was significantly related to MVPA time and it explained 0.4％ variance.Perceived behavioral control(β=0.496,P＜0.01) and attitude(β=0.155,P＜0.01) were significantly associated with MVPA intention and explained 1.8％ variance.Conclusion The average MVPA time of children and adolescents in this study do not achieve the international recommendation level and the behavioral intention determines their MVPA time.
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[Objective] To investigate the effects of aerobic exercise on osteoporosis in the elderly.[Methods]Sixty elderly were divided into two groups:control group(n=30)without conscious and regular exercise and experimental group(n=30)with aerobic exercise.After 12 months,bone mineral density in lateral lumbar spine 2~4(L2~4),left side of femoral neck(L-FN),left side of greater trochanter(L-TR)and wards area were measured for by dual energy X-ray absorptiometry(DEXA)for the statistical analysis.[Results]The bone-mass-loss after the experiment was obviously lower than before;bone mineral density(BMD)of control group was lower than experimental group in the four parts.The difference(P