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 .
Insulin-like growth factor I in skeletal muscle after weight-lifting exercise in frail elders.
To assess muscle remodeling and functional adaptation to exercise and diet interventions , 26 men and women aged 72 - 98 yr underwent a vastus lateralis biopsy before and after placebo control condition , and progressive resistance training , multinutrient supplementation , or both .  Type II atrophy , Z b and , and myofibril damage were present at baseline . Combined weight lifting and nutritional supplementation increased strength by 257 + /- 62 % ( P = 0.0001 ) and type II fiber area by 10.1 + /- 9.0 % ( P = 0.033 ) , with a similar trend for type I fiber area ( + 12.8 + /- 22.2 % ) . Exercise was associated with a 2 . 5-fold increase in neonatal myosin staining ( P = 0.0009 ) and an increase of 491 + /- 137 % ( P < 0.0001 ) in IGF-I staining . Ultrastructural damage increased by 141 + /- 59 % after exercise training ( P = 0.034 ) . Strength increases were largest in those with the greatest increases in myosin , IGF-I , damage , and caloric intake during the trial . Age-related sarcopenia appears largely confined to type II muscle fibers . Frail elders respond robustly to resistance training with musculoskeletal remodeling , and significant increases in muscle area are possible with resistance training in combination with adequate energy intakes
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 .