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 .
Muscle hypertrophy response to resistance training in older women.
We conducted a 12-wk resistance training program in elderly women [ mean age 69 + /- 1.0 ( SE ) yr ] to determine whether increases in muscle strength are associated with changes in cross-sectional fiber area of the vastus lateralis muscle . Twenty-seven healthy women were r and omly assigned to either a control or exercise group . The program was satisfactorily completed and adequate biopsy material obtained from 6 controls and 13 exercisers . After initial testing of baseline maximal strength , exercisers began a training regimen consisting of seven exercises that stressed primary muscle groups of the lower extremities . No active intervention was prescribed for the controls . Increases in muscle strength of the exercising subjects were significant compared with baseline values ( 28 - 115 % ) in all muscle groups . No significant strength changes were observed in the controls . Cross-sectional area of type II muscle fibers significantly increased in the exercisers ( 20.1 + /- 6.8 % , P = 0.02 ) compared with baseline . In contrast , no significant change in type II fiber area was observed in the controls . No significant changes in type I fiber area were found in either group . We conclude that a program of resistance exercise can be safely carried out by elderly women , such a program significantly increases muscle strength , and such gains are due , at least in part , to muscle hypertrophy
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 .