PRT results in improvements to muscle strength and some aspects of functional limitation , such as gait speed , in older adults .
However , based on current data , the effect of PRT on physical disability remains unclear .
Further , due to the poor reporting of adverse events in trials , it is difficult to evaluate the risks associated with PRT
BACKGROUND The aim of this systematic review was to quantify the effectiveness of progressive resistance strength training ( PRT ) to reduce  physical disability in older people .
Efficacy of heavy-resistance training for active women over sixty: muscular strength, body composition, and program adherence.
OBJECTIVE To determine the effects of resistance training on muscular strength , body composition ( percent fat and lean tissue mass ) , and program adherence in active women over 60 years of age . DESIGN This study was design ed as a stratified , r and omized , non-blinded trial . Subjects were stratified into rank-ordered pairs by level of physical activity according to the Blair Seven-Day Recall , then r and omly assigned into either a weight-training ( WT , n = 18 ) or control ( CON , n = 18 ) group . PARTICIPANTS AND SETTING Thirty-six women over the age of 60 ( 67.1 + /- 1.5 , chi + /- SE ) were recruited from the San Diego community . All subjects had to be engaging in some form of aerobic exercise  at least 3 days each week for a minimum of 6 months . MEASUREMENTS AND INTERVENTION : Subjects engaged in isotonic training 3 days/week on Polaris machines at a target intensity of 80 % of the 1 repetition maximum ( 1 RM ) for three sets of seven exercises selected to train major muscle groups of the trunk and upper and lower body . The 1 RM was re-tested every 6 weeks in WT and the workload adjusted to maintain target intensity . The 1 RM was tested at 0 , 12 , and 24 weeks in CON . Body fatness and lean tissue mass , excluding skeletal mass , were assessed at 0 and 24 weeks by dual energy radiography using a total body scan . RESULTS Increases in muscle strength of the weight trainers were significant for all seven exercises ( 5%-65 % ) , with the greatest gains in the shoulder and trunk muscles . Percent body fat of weight trainers decreased significantly ( from 38.8 % to 37.9 % , P < 0.05 ) , while lean tissue mass increased by 1.5 kg ( P < 0.01 ) . No changes in body composition were observed in control subjects . Overall program adherence was 83 % ( 15 weight trainers and 15 control women completed the study ) . Monthly attendance averaged 86.8 + /- 3.3 % , with no incidence of injury during the training sessions . CONCLUSIONS These data indicate that heavy-resistance weight training is safe and enjoyable for older women and that meaningful gains in muscular strength and body composition can be made even in women who are already highly active
PRT results in improvements to muscle strength and some aspects of functional limitation , such as gait speed , in older adults .
However , based on current data , the effect of PRT on physical disability remains unclear .
Further , due to the poor reporting of adverse events in trials , it is difficult to evaluate the risks associated with PRT
BACKGROUND The aim of this systematic review was to quantify the effectiveness of progressive resistance strength training ( PRT ) to reduce  physical disability in older people .