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 .
Regular participation in sports is associated with enhanced physical fitness and lower fat mass in prepubertal boys
OBJECTIVE : To study the effect of physical activity on whole body fat ( BF ) , its regional deposition and the influence of body fatness on physical performance in prepubertal children . DESSIGN : Cross-sectional study .SUBJECTS : A total of 114 boys ( 9.4±1.5 y , Tanner I – II ) , r and omly sample d from the population of Gran Canaria ( Spain ) , 63 of them physically active ( PA , at least 3 h per week during the previous year ) and 51 nonphysically active ( non-PA ) .  MEASUREMENTS : Body composition ( DXA ) , anthropometric variables ( body circumferences and skinfolds ) and physical fitness were determined in all subjects . RESULTS : The PA obtained better results in maximal oxygen uptake , isometric leg extension force , vertical jump ( muscular power ) , and 300 m ( anaerobic capacity ) and 30 m running tests ( speed ) than the non-PA . A lower percentage of body fat ( % BF ) ( 4 U less , P<0.05 ) , whole BF mass ( 36 % less , P<0.05 ) and regional fat mass ( 28 , 25 , and 30 % less in the trunk , legs and arms , respectively , all P<0.05 ) was observed in the PA compared to the non-PA . The waist and hip circumferences correlated more closely with both the fat mass accumulated in the trunk region and the % BF ( r=0.81–0.95 , P<0.001 ) than the waist-to-hip ratio ( WHR ) . The WHR correlated with the percentage of the whole fat mass accumulated in the trunk ( PFT ) ( r=0.52–0.53 , P<0.001 ) . In both groups , the PFT increased curvilinearly with the % BF , regardless of the level of physical activity . ANCOVA analysis revealed that total and regional fat masses explained less than 40 % of the difference in performance between the PA and non-PA group . The mean speed in the 30 m running test ( V30 ) , combined with the height and whole body mass , has predictive value for the BF mass ( R=0.98 , P<0.001 ) . The % BF may be estimated from the body mass index ( BMI ) and V30 ( % BF=8.09 + 2.44 · BMI ( kg m−2)–5.8·V30 ( m s−1 ) , R=0.94 , P<0.001 ) in prepubertal boys . CONCLUSIONS : Regular participation in at least 3 h per week of sports activities and competitions on top of the compulsory physical education program is associated with increased physical fitness , lower whole body and trunkal fat mass in prepubertal boys
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 .