This review found that muscle strength , balance , and endurance can be improved by physical activity in people aged 40 - 65 years .
There were bigger effects on muscle strength from programs that used resistance exercises , indicating the need to include a resistance training component if strength enhancement is the goal
QUESTION Can physical activity  in adults aged 40 - 65 years enhance strength and balance and prevent falls ?
Effect of resistance exercise on bone mineral density in premenopausal women.
OBJECTIVE To assess the effect of 9 months of strength training on total body and regional bone mineral density ( BMD , g/cm(2 ) ) in 58 premenopausal women aged 30 - 50 years . METHODS Participants were r and omized to either twice weekly supervised strength training for 15 weeks followed by 24 weeks of unsupervised training ( treatment group ) or control group . Height , weight , maximal muscular strength , nutrient intake and physical activity were assessed . Total body dual energy X-ray absorptiometry ( DXA , Lunar Prodigy ) scans were taken and analyzed for body composition ( lean and fat mass ) , and BMD for total body and its sub-regions ( spine , hip , arms and legs ) . All measurements were performed at baseline , 15 and 39 weeks . Analysis of covariance was used to assess group differences in BMD change adjusted for baseline BMD , weight , energy and calcium intake . RESULTS At baseline , the two groups had similar BMD and body size characteristics ( P<0.05 for all ) , except that the treatment group had lower body weight ( -7.1 kg ) , and higher energy ( + 259 kJ/d ) and calcium ( + 232 mg/d ) intake at baseline . Adjusted % change in BMD over 15 weeks ( 0.5 % vs. 0.4 % ) or 39 weeks ( 0.9 % vs. 1.2 % ) did not differ significantly between the exercise and control groups , respectively . The exercise group increased BMD at the spine and legs ( 1 - 2.2 % ) , while there was no change in the controls , but differences between groups were not significant . CONCLUSION Strength training over 9 months did not lead to significantly greater change in total body or regional BMD in premenopausal women
This review found that muscle strength , balance , and endurance can be improved by physical activity in people aged 40 - 65 years .
There were bigger effects on muscle strength from programs that used resistance exercises , indicating the need to include a resistance training component if strength enhancement is the goal
QUESTION Can physical activity  in adults aged 40 - 65 years enhance strength and balance and prevent falls ?