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 .
Large energetic adaptations of elderly muscle to resistance and endurance training.
This study determined the cellular energetic and structural adaptations of elderly muscle to exercise training .  Forty male and female subjects ( 69.2 + /- 0.6 yr ) were assigned to a control group or 6 mo of endurance ( ET ) or resistance training ( RT ) . We used magnetic resonance spectroscopy and imaging to characterize energetic properties and size of the quadriceps femoris muscle . The phosphocreatine and pH changes during exercise yielded the muscle oxidative properties , glycolytic ATP synthesis , and contractile ATP dem and . Muscle biopsies taken from the same site as the magnetic resonance measurements were used to determine myosin heavy chain isoforms , metabolite concentrations , and mitochondrial volume densities . The ET group showed changes in all energetic pathways : oxidative capacity ( + 31 % ) , contractile ATP dem and ( -21 % ) , and glycolytic ATP supply ( -56 % ) . The RT group had a large increase in oxidative capacity ( 57 % ) . Only the RT group exhibited change in structural properties : a rise in mitochondrial volume density ( 31 % ) and muscle size ( 10 % ) . These results demonstrate large energetic , but smaller structural , adaptations by elderly muscle with exercise training . The rise in oxidative properties with both ET and RT suggests that the aerobic pathway is particularly sensitive to exercise training in elderly muscle . Thus elderly muscle remains adaptable to chronic exercise , with large energetic changes accompanying both ET and RT
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 .