PRT had a large positive effect on strength ( 41 trials , 1955 participants ) , but there was statistical heterogeneity that was not explained by differences in study quality , participant characteristics or the exercise program .
REVIEW ER 'S CONCLUSIONS PRT appears to be an effective intervention to increase strength in older people and has a positive effect on some functional limitations .
However , the effect of this intervention on more substantive outcomes such as measures of disability or HRQOL remains unclear .
BACKGROUND Muscle weakness in old age , is associated with physical disability and an increased risk of falls .
Progressive resistance strength ( PRT ) training exercises ( i.e. movements performed against a specific external force that is regularly increased during training ) are design ed to increase strength in older people .
OBJECTIVES To assess the effect of PRT on measures of physical disability , functional limitation and impairment in older people  , and identify adverse events .
Dynamic muscle strength alterations to detraining and retraining in elderly men.
To investigate the effects of cessation and subsequent resumption of training on muscle strength in elderly men , 11 men ( aged 65 - 77 years ) , just completing a 24-week r and omized controlled trial of recombinant human growth hormone ( rhGH ) and resistance exercise ( rhGH  , n = 6 ; placebo , n = 5 ) , detrained for 12 weeks and subsequently retrained for 8 weeks . During the detraining and retraining phase , subjects did not receive rhGH . The resistance programme included three sets of eight repetitions at 75 % of one-repetition maximum ( 1-RM ) , three times per week , for 10 upper and lower body exercises .  Dynamic muscle strength was assessed by the 1-RM method every 2 weeks for 44 weeks . Needle biopsies of vastus lateralis muscle were obtained from seven men . Muscle strength increased during initial training by 40.4 + /- 5.5 % ( mean + /- SEM ) , ranging from 26.0 + /- 5.0 to 83.9 + /- 15.6 % , depending on muscle group . Increased strength was accompanied by hypertrophy ( P < 0.05 ) of type I ( 17.4 + /- 4.1 % ) and II ( 25.8 + /- 12.4 % ) muscle fibres . Of initial strength gains , only 29.9 + /- 5.2 % was lost with detraining . However , type I and II fibre cross-sectional area reverted to pretraining values . After 8 weeks of retraining , muscle strength returned to trained values , but without a significant change in fibre morphology . The results indicate that elderly men lose some muscle strength following short-term detraining , but that only a brief period of retraining suffices to regain maximal strength . Reversal of fibre cross-sectional area with detraining , and only modest improvement with retraining , suggests that much of the retention in strength with detraining and reacquisition of lost strength with retraining reflects neural adaptation
PRT had a large positive effect on strength ( 41 trials , 1955 participants ) , but there was statistical heterogeneity that was not explained by differences in study quality , participant characteristics or the exercise program .
REVIEW ER 'S CONCLUSIONS PRT appears to be an effective intervention to increase strength in older people and has a positive effect on some functional limitations .
However , the effect of this intervention on more substantive outcomes such as measures of disability or HRQOL remains unclear .
BACKGROUND Muscle weakness in old age , is associated with physical disability and an increased risk of falls .
Progressive resistance strength ( PRT ) training exercises ( i.e. movements performed against a specific external force that is regularly increased during training ) are design ed to increase strength in older people .
OBJECTIVES To assess the effect of PRT on measures of physical disability , functional limitation and impairment in older people  , and identify adverse events .