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 .
Systematic strength training as a model of therapeutic intervention. A controlled trial in postmenopausal women with osteopenia.
Physical exercise is often recommended as a therapeutic tool to combat pre- and postmenopausal loss of bone density . However , the relationship between training dosage ( intensity , duration , frequency ) and the effect on bone density still is undergoing discussion . Furthermore , the exercise quantification programs are often described so inadequately that they are neither quantitatively nor qualitatively reproducible . The aim of this investigation was to determine whether a clearly defined training of muscle strength , under defined safety aspects , performed only twice weekly , can counteract bone density loss in women with postmenopausal osteopenia . Data from 16 women in the training group ( age , 63.6 + /- 6.2 yr ) and 15 women in the control group ( age , 67.4 + /-9.7 yr ) , of comparable height and weight , were evaluated .  Strength training was performed for 6 mo as continually adapted strength training , providing an intensity of about 70 % of each test person 's one repetition maximum . Bone mineral density of lumbar vertebrae 2 to 4 and the femoral neck was measured by dual-energy x-ray absorptiometry . Maximum performance in watts and parameters of hemodynamics were controlled with a bicycle ergometer test to maximal effort . In addition , metabolic data were assessed . In the lumbar spine and femoral neck , the training group showed no significant changes , whereas the control group demonstrated a significant loss of bone mineral density , especially in the femoral neck ( P<0.05 ) . The strength increase was highly significant in all exercised muscle groups , rising to about 70 % above the pretraining status ( P<0.001 ) . Heart rate and blood pressure data indicated a slight economization , metabolism was not significantly influenced . Based on these findings , we conclude that continually adapted strength training is an effective , safe , reproducible , and adaptable method of therapeutic strength training , following only two exercise sessions per week
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 .