The heterogeneity in reported effects was reduced in higher quality studies , when physical activity was self-directed with some professional guidance and when there was on-going professional support .
Our review suggests that physical activity interventions have a moderate effect on self reported physical activity and cardio-respiratory fitness , but not on achieving a predetermined level of physical activity .
Due to the clinical and statistical heterogeneity of the studies , only limited conclusions can be drawn about the effectiveness of individual components of the interventions .
BACKGROUND Little is known about the effectiveness of strategies to enable people to achieve an increase in their physical activity .
OBJECTIVES To assess the effects of interventions for promoting physical activity in adults aged 16 years and older , not living in an institution .
Effects of intermittent exercise and use of home exercise equipment on adherence, weight loss, and fitness in overweight women: a randomized trial.
CONTEXT Enhancing participation in long-term exercise may translate into improved long-term weight loss  in overweight adults . OBJECTIVES To compare the effects of intermittent with traditional continuous exercise on weight loss , adherence , and fitness , and to examine the effect of combining intermittent exercise with that using home exercise equipment . DESIGN R and omized trial from September 1996 through September 1998 . SETTING AND PARTICIPANTS A total of 148 sedentary , overweight ( mean [ SD ] body mass index , 32.8 [ 4.0 ] kg/m2 ) women ( mean [ SD ] age , 36.7 [ 5.6 ] years ) in a university-based weight control program . INTERVENTIONS Eighteen-month behavioral weight control program with 3 groups : long-bout exercise ( LB ) , multiple short-bout exercise ( SB ) , or multiple short-bout exercise with home exercise equipment ( SBEQ ) using a treadmill . MAIN OUTCOME MEASURES Body weight , body composition , cardiorespiratory fitness , and exercise adherence . RESULTS Of 148 subjects , 115 ( 78 % ) completed the 18-month program . At 18 months , mean ( SD ) weight loss was significantly greater in subjects in the SBEQ group compared with subjects in the SB group ( -7.4 [ 7.8 ] kg vs -3.7 [ 6.6 ] kg ; P<.05 ) . Mean ( SD ) weight loss for subjects in the LB group ( -5.8 [ 7.1 ] kg ) was not significantly different than for subjects in the SB or SBEQ groups . Subjects in the SBEQ group maintained a higher level of exercise than subjects in both the SB and LB groups ( P<.05 ) at 13 to 18 months of treatment . All groups showed an increase in cardiorespiratory fitness from baseline to 18 months , with no difference between groups . Mean ( SD ) weight loss at 18 months was significantly greater in individuals exercising more than 200 min/wk throughout the intervention ( -13.1 [ 8.0 ] kg ) compared with individuals exercising 150 to 200 min/wk ( -8.5 [ 5.8 ] kg ) or less than 150 min/wk ( -3.5 [ 6.5 ] kg ) ( P<.05 ) . CONCLUSIONS Compared with the LB group , subjects in the SB group did not experience improved long-term weight loss , exercise participation , or cardiorespiratory fitness . Access to home exercise equipment facilitated the maintenance of SB , which may improve long-term weight loss . A dose-response relationship exists between amount of exercise and long-term  weight loss  in overweight adult women
The heterogeneity in reported effects was reduced in higher quality studies , when physical activity was self-directed with some professional guidance and when there was on-going professional support .
Our review suggests that physical activity interventions have a moderate effect on self reported physical activity and cardio-respiratory fitness , but not on achieving a predetermined level of physical activity .
Due to the clinical and statistical heterogeneity of the studies , only limited conclusions can be drawn about the effectiveness of individual components of the interventions .
BACKGROUND Little is known about the effectiveness of strategies to enable people to achieve an increase in their physical activity .
OBJECTIVES To assess the effects of interventions for promoting physical activity in adults aged 16 years and older , not living in an institution .