Results There was consistent evidence for a positive association between MF and physical activity .
For both MF components , there was support for objective ly measured physical activity , particularly for activity of vigorous intensity .
Sports participation was also consistently linked with both MF components , whereas the association with active transport was inconsistent .
For both MF components , associations with sedentary behaviors were inconsistent irrespective of measurement method , and the association between MF and sleep was considered uncertain .
Conclusions The available evidence supports a link between MF and physical activity , particularly for vigorous intensity activity and organized sports participation .
Background Muscular fitness ( MF ) is considered a powerful marker of health , but the extent to which common health behaviors are associated with MF during childhood and adolescence is currently unclear .
Objective We conducted a systematic review of studies investigating associations between MF ( i.e. , strength/power , local muscular endurance ) and physical activity , sedentary behaviors , and sleep in children and adolescents .
High-intensity training increases spontaneous physical activity in children: a randomized controlled study.
OBJECTIVE To test the hypothesis that resistance training may increase spontaneous physical activity in children . STUDY DESIGN Two junior ice hockey teams were r and omly assigned to unchanged training schedules  ( team ZSC , 21 boys ; mean age , 13.2 years ) or to participate twice weekly in guided resistance training for 4 months ( team GCK , 25 boys ; mean age , 13.4 years ) . Spontaneous physical activity energy expenditure ( SpAEE ; 3-axial accelerometry for 7 days ) , muscle strength , and body composition ( dual energy x-ray absorptiometry ) were measured at 0 , 4 , and 12 months . RESULTS Baseline measures did not differ in the groups , except for higher leg and trunk strength in team ZSC . In the intervention group compared with the control group , SpAEE significantly ( P < or = .02 ) increased at 4 months ( + 25.5 % versus 0 % ) and 12 months ( + 13.5 % versus -9.5 % ) . Leg and arm strength increased because of training intervention ; all other variables were unchanged . None of these variables correlated with changes in SpAEE . CONCLUSION In boys who play ice hockey , spontaneous physical activity is inducible with resistance training ; this effect seems to be independent of changes in body composition and strength . If this was confirmed in unselected children , resistance training might be a new strategy for childhood obesity prevention programs
Results There was consistent evidence for a positive association between MF and physical activity .
For both MF components , there was support for objective ly measured physical activity , particularly for activity of vigorous intensity .
Sports participation was also consistently linked with both MF components , whereas the association with active transport was inconsistent .
For both MF components , associations with sedentary behaviors were inconsistent irrespective of measurement method , and the association between MF and sleep was considered uncertain .
Conclusions The available evidence supports a link between MF and physical activity , particularly for vigorous intensity activity and organized sports participation .
Background Muscular fitness ( MF ) is considered a powerful marker of health , but the extent to which common health behaviors are associated with MF during childhood and adolescence is currently unclear .
Objective We conducted a systematic review of studies investigating associations between MF ( i.e. , strength/power , local muscular endurance ) and physical activity , sedentary behaviors , and sleep in children and adolescents .