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 .
IGF-1 bioavailability is increased by resistance training in older women with low bone mineral density
We investigated if long-term resistance training would increase insulin-like growth factor-1 ( IGF-1 ) bioavailabilty at rest in older women ( 68+/-1 years ) with low bone mineral density .  IGF-1 levels were significantly lower ( P<0.05 ) , and insulin-like growth factor binding proteins -1 and -3 ( IGFBP-1 and IGFBP-3 ) significantly higher than an age-matched healthy normal group . Resistance training result ed in significant ( P<0.05 ) increases in repetition maximums across all exercises ( range 41 - 78 % ) . Resting IGF-1 levels were significantly ( P<0.05 ) elevated ( 70 % ) by the resistance training whereas no significant changes occurred in IGFBP-1 and IGFBP-3 levels . IGFBP-1/IGF-1 and IGFBP-3/IGF-1 ratios were significantly decreased ( approximately - 50 % ) as a result of resistance training ( P<0.05 ) . Thus , IGF-1 bioavailability was increased as a result of resistance training induced increases in IGF-1 levels in older women with low bone mineral density . These alterations in the IGF-1 system may be contributing to the significant strength gain observed with the resistance training in this population
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 .