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 .
Randomized placebo-controlled trial of brisk walking in the prevention of postmenopausal osteoporosis.
OBJECTIVE to evaluate the effects of brisk walking on bone mineral density in women who had suffered an upper limb fracture . DESIGN r and omized placebo-controlled trial . Assessment s of bone mineral density were made before and at 1 and 2 years after intervention . St and ardized and vali date d measures of physical capacity , self-rated health status and falls were used . SETTING district general hospital outpatient department . SUBJECTS 165 women drawn from local accident and emergency departments with a history of fracture of an upper limb in the previous 2 years . Women were r and omly allocated to intervention ( self-paced brisk walking ) or placebo ( upper limb exercises ) groups . INTERVENTION both groups were seen at 3-monthly intervals to assess progress , measure physical capacity and maintain enthusiasm . The brisk-walking group were instructed to progressively increase the amount and speed of walking in a manner that suited them . The upper limb exercise placebo group were asked to carry out a series of exercises design ed to improve flexibility and fine h and movements , appropriate for a past history of upper limb fracture . RESULTS drop-outs from both intervention and placebo groups were substantial ( 41 % ) , although there were no significant differences in bone mineral density , physical capacity or health status between drop-outs and participants . At 2 years , among those completing the trial , bone mineral density at the femoral neck had fallen in the placebo group to a greater extent than in the brisk-walking group [ mean net difference between intervention and placebo groups 0.019 g/cm2 , 95 % confidence interval ( CI ) -0.0026 to + 0.041 g/cm2 , P = 0.056 ] . Lumbar spine bone mineral density had increased to a similar extent ( + 0.017 g/cm2 ) in both groups . The cumulative risk of falls was higher in the brisk-walking group ( excess risk of 15 per 100 person-years , 95 % CI 1.4 - 29 per 100 person-years , P < 0.05 ) . There were no significant differences in clinical or spinal x-ray fracture risk or self-rated health status between intervention and placebo groups . CONCLUSION the promotion of exercise through brisk-walking advice given by nursing staff may have a small , but clinical ly important , impact on bone mineral density but is associated with an increased risk of falls . Self-paced brisk walking is difficult to evaluate in r and omized controlled trials because of drop-outs , placebo group exercise , limited compliance and lack of st and ardization of the duration and intensity of walking . Further work is needed to evaluate the best means of safely achieving increased activity levels in different groups , such as older women and those at high risk of fractures
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 .