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 .
Heavy-resistance training in older Scandinavian men and women: short- and long-term effects on arm and leg muscles.
The short- and long-term effects of heavy-resistance training ( 85 % of one-repetition maximum ( RM ) ) on elbow flexion and knee extension dynamic and isokinetic strength and on morphology in the biceps brachii and vastus lateralis muscles were evaluated during 1 year in 35 Sc and inavian men and women , aged 70 - 77 years , 12 of whom formed a control group . After the first 11 weeks of training ( n = 23 ; 3 times/week )  elbow flexion and knee extension dynamic strength ( 1 RM ) had increased [ mean + /- SD ] 49 % + /- 16 and 163 % + /- 75 , respectively , with no significant difference between men and women . For the following 27 weeks , strength was maintained with one training session per week ( n = 12 ) but dropped without training ( n = 11 ) . After the final 11 weeks of training ( n = 11 ; 3 times/week ) , strength had further increased 32 % + /- 16 in both the arm and the leg . Isokinetic strength measurements ( Cybex II ; 30 degrees/s ) revealed similar but smaller gains than for dynamic strength . Muscle biopsies ( n = 20 ) taken at the start and after the first 11 weeks of training showed a significant increase in the area of both type 1 and type 2 fibers in the biceps brachii muscle and a positive significant correlation between the percentage increase in the proportional area of type 2 fibers in the vastus lateralis muscle and the percentage increase in knee extension dynamic muscle strength . In conclusion , older Sc and inavian men and women have a high capacity both to improve and to maintain muscle strength , some of which is mediated through an adaptation in the muscle fiber type population
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 .