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 .
Former exercisers of an 18-month intervention display residual aBMD benefits compared with control women 3.5 years post-intervention: a follow-up of a randomized controlled high-impact trial
Exercise is recommended to enhance bone health but data on the maintenance of the exercise-induced bone benefit is sparse . The purpose of the study was to assess the maintenance of the musculoskeletal benefits obtained in an 18-month intervention of  high-impact exercise  in premenopausal women ( 34 former trainees and 31 controls ) . Physical performance and areal bone mineral density ( aBMD , g/cm2 ) were measured at baseline , after 18 months , and after 5 years . All significant 18-month improvements relative to controls in the trainees ’ neuromuscular performance ( isometric leg press , and vertical jump with and without additional 10 % weight of the body mass ) had been lost at the 5-year follow-up . However , since the changes in aBMD in both former trainees and controls by time were similar , the  exercise-induced aBMD gain ( i.e. the mean statistically significant intergroup differences of 1–3 % in favor of the trainees ) was maintained at the femoral neck , distal femur , patella , proximal tibia , and calcaneus at the 5-year follow-up . At lumbar spine , the difference was 1.7 % at both 18-month and at the 5-year follow-ups but the difference was not statistically significant ( NS ) in the latter follow-up . At the trochanter and unloaded distal radius , the intergroup aBMD differences were NS at both the 18-month and 5-year follow-ups . In conclusion , the bone sites aBMD increased in response to the 18-month intervention , also demonstrated maintenance of this gain 3.5 years after the intervention . In contrast , the exercise-induced improvements in the neuromuscular performance vanished during the post intervention follow-up . These findings suggest the possibility of long-term bone benefits of high-impact training in 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 .