There is a large body of evidence from all study design s which suggests that decreasing any type of sedentary time is associated with lower health risk in youth aged 5 - 17 years .
In particular , the evidence suggests that daily TV viewing in excess of 2 hours is associated with reduced physical and psychosocial health , and that lowering sedentary time leads to reductions in BMI
Accumulating evidence suggests that , independent of physical activity levels , sedentary behaviours are associated with increased risk of cardio-metabolic disease , all-cause mortality , and a variety of physiological and psychological problems .
Therefore , the purpose of this systematic review is to determine the relationship between sedentary behaviour and health indicators in school-aged children and youth aged 5 - 17 years .
Intervention centred on adolescents' physical activity and sedentary behaviour (ICAPS): concept and 6-month results
OBJECTIVE : To evaluate the 6-month impact of a physical activity ( PA ) multilevel intervention on activity patterns and psychological predictors of  PA among adolescents . The intervention was directed at changing knowledge and attitudes and at providing social support and environmental conditions that encourage PA of adolescents inside and outside school . SUBJECTS AND DESIGN : R and omised , controlled ongoing field trial ( ICAPS ) in middle-school 's first-level adolescents from eight schools selected in the department of the Bas-Rhin ( Eastern France ) with a cohort of 954 adolescents ( 92 % of the eligible students ) initially aged 11.7±0.6 y. The 6-month changes in participation in leisure organised PA ( LOPA ) , high sedentary ( SED ) behaviour ( > 3h/day ) , self-efficacy ( SELF ) and intention ( INTENT ) towards PA  were analysed after controlling for baseline measures and different covariables ( age , overweight , socioprofessional occupation ) , taking into account the cluster r and omisation design . RESULTS : The proportion of intervention adolescents not engaged in organised PA  was reduced by 50 % whereas it was unchanged among control students . After adjustment for baseline covariables , LOPA participation significantly increased among the intervention adolescents ( odds ratio ( 95 % confidence interval ) (OR)=3.38 ( 1.42–8.05 ) in girls ; 1.73 ( 1.12–2.66 ) in boys ) , while high SED was reduced ( OR=0.54 ( 0.38–0.77 ) in girls ; 0.52 ( 0.35–0.76 ) in boys ) . The intervention improved SELF in girls , whatever their baseline LOPA ( P<10−4 ) and INTENT in girls with no baseline LOPA ( P=0.04 ) . SELF tended to improve in boys with no baseline LOPA , without reaching statistical significance . When included in the regression , follow-up LOPA was associated with improvement of SELF in girls ( P=0.02 ) and of INTENT in girls with no baseline PA ( P<0.02 ) . The intervention effect was then attenuated . CONCLUSION : After 6 months of intervention , ICAPS was associated with a significant improvement of activity patterns and psychological predictors , indicating a promising approach for modifying the long-term PA level of adolescents
There is a large body of evidence from all study design s which suggests that decreasing any type of sedentary time is associated with lower health risk in youth aged 5 - 17 years .
In particular , the evidence suggests that daily TV viewing in excess of 2 hours is associated with reduced physical and psychosocial health , and that lowering sedentary time leads to reductions in BMI
Accumulating evidence suggests that , independent of physical activity levels , sedentary behaviours are associated with increased risk of cardio-metabolic disease , all-cause mortality , and a variety of physiological and psychological problems .
Therefore , the purpose of this systematic review is to determine the relationship between sedentary behaviour and health indicators in school-aged children and youth aged 5 - 17 years .