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 .
Once-weekly resistance exercise improves muscle strength and neuromuscular performance in older adults.
OBJECTIVE To determine the effect of frequency of resistive training on gain in muscle strength and neuromuscular performance in healthy older adults . DESIGN A r and omized controlled trial with subjects assigned either to high-intensity resistance training 1 ( EX1 ) , 2 ( EX2 ) , or 3 ( EX3 ) days per week for 24 weeks or to a control group ( CO ) . SETTING An exercise facility at an academic medical center . SUBJECTS Forty-six community-dwelling healthy men ( n = 29 ) and women ( n = 17 ) aged 65 to 79 years . INTERVENTION Progressive resistance training consisting of three sets of eight exercises targeting major muscle groups of the upper and lower body , at 80 % of one-repetition maximum ( 1-RM ) for eight repetitions , either 1 , 2 , or 3 days per week . MEASURES Dynamic muscle strength ( 1-RM ) using isotonic equipment every 4 weeks , bone mineral density and body composition by dual energy X-ray absorptiometry ( DXA ) , and neuromuscular performance by timed chair rise and 6-meter backward t and em walk . RESULTS For each of the eight exercises , muscle strength increased in the exercise groups relative to CO ( P < .01 ) , with no difference among EX1 , EX2 and EX3 groups at any measurement interval . Percent change averaged 3.9 + /- 2.4 ( CO ) , 37.0 + /- 15.2 ( EX1 ) , 41.9 + /- 18.2 ( EX2 ) , and 39.7 + /- 9.8 ( EX3 ) . The time to rise successfully from the chair 5 times decreased significantly ( P < .01 ) at 24 weeks , whereas improvement in the 6-meter backward t and em walk approached significance ( P = .10 ) in the three exercise groups compared with CO . Changes in chair rise ability were correlated to percent changes in quadriceps strength ( r = -0.40 , P < .01 ) and lean mass ( r = -0.40 , P < .01 ) . CONCLUSIONS A program of once or twice weekly resistance exercise achieves muscle strength gains similar to 3 days per week training in older adults and is associated with improved neuromuscular performance . Such improvement could potentially reduce the risk of falls and fracture in older adults
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 .