human
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Periodization is the most effective approach to resistance training ; however , optimal cycle lengths for older persons are not known . This study examined the duration s of performance increments , plateaus , and decrements in women , ages 61 - 75 yr , over 9 wk of isokinetic training .  After a 2-wk adaptation cycle , older women trained for either power ( PWR ; 4.73 rad/s ; n = 9 ) or strength ( STR ; 1.05 rad/s ; n = 8) , 3 days/wk with a 1-day recovery between sessions . Repetitions were initially selected to equilibrate work volume between groups . Average power ( AP ) , peak torque ( PT ) , and total work ( TW ) curves were analyzed using forward and backward stepwise regression to ascertain inflections and plateaus . PWR training produced the highest AP , whereas STR produced the highest PT . TW was similar between groups . The AP curves of the PWR group initially showed a steep positive slope and then plateaued during week 3 . The right leg plateau lasted throughout training , whereas the left leg showed another positive inflection during weeks 7 and 8 . PWR group TW curves showed positive slopes throughout training . STR group PT curves for both legs showed initial positive slopes peaking between weeks 3 and 4 and declining thereafter . The TW curves for both legs showed slight negative slopes across the first 2 wk , steep positive slopes during weeks 3 - 6 , and a final plateau . Because improvements plateau early during PWR and STR training , isokinetic training prescriptions for optimizing strength and power improvements in older persons should use cycles of 3 - 4 wk to maximize gains BACKGROUND Muscle power ( force x velocity ) recedes at a faster rate than strength with age and may also be a stronger predictor of fall risk and functional decline . The optimal training paradigm for improving muscle power in older adults is not known , although some literature suggests high velocity , low load training is optimal in young adults . METHODS One hundred twelve healthy older adults ( 69 + /- 6 years ) were r and omly assigned to either explosive resistance training at 20 % ( G20 ) , 50 % ( G50 ) , or 80 % ( G80 ) one repetition maximum ( 1RM ) for 8 - 12 weeks or to a nontraining control group ( CON ) . Participants trained twice per week ( five exercises ; three sets of eight rapidly concentric and slow eccentric repetitions ) using pneumatic resistance machines . Repeated- measures analysis of variance and covariance ( ANOVA and ANCOVA ) were used to determine the effects of training . RESULTS Average peak power increased significantly and similarly in G80 ( 14 + /- 8 % ) , G50 ( 15 + /- 9 % ) , and G20 ( 14 + /- 6 % ) compared to CON ( 3 + /- 6 % ) ( p < .0001 ) . By contrast , a positive dose-response relationship with training intensity was observed for relative changes in average strength ( r = .40 , p = .0009 ) and endurance ( r = .43 , p = .0005 ) . Average strength increased in G80 ( 20 + /- 7 % ) , G50 ( 16 + /- 7 % ) , and G20 ( 13 + /- 7 % ) compared to CON ( 4 + /- 4 % ) ( p < .0001 ) . Average muscle endurance increased in G80 ( 185 + /- 126 % , p < .0001 ) , G50 ( 103 + /- 75 % , p = .0004 ) , and G20 ( 82 + /- 57 % , p = .0078 ) compared to CON ( 28 + /- 29 % ) . CONCLUSION Peak muscle power may be improved similarly using light , moderate , or heavy resistances , whereas there is a dose-response relationship between training intensity and muscle strength and endurance changes . Therefore , using heavy loads during explosive resistance training may be the most effective strategy to achieve simultaneous improvements in muscle strength , power , and endurance in older adults OBJECTIVE To determine the effect of training intensity on the contributions of force and velocity to improvements in peak power ( PP ) after explosive resistance training in older adults . METHODS 112 healthy older adults ( 69 + /- 6 yr ) were r and omized to explosive resistance training at 20 % ( G20 ) , 50 % ( G50 ) , or 80 % ( G80 ) maximal strength ( 1-repetition maximum ) for 8 - 12 wk ( twice weekly , 5 exercises , 3 sets of 8 explosive concentric/slow eccentric repetitions ) using pneumatic resistance machines or a nontraining control group ( CON ) . RESULTS Force at peak power ( FPP ) increased significantly and similarly among training groups compared with CON . Velocity at peak power ( VPP ) did not improve significantly and remained similar between all groups . Force contributed significantly more to PP production in G80 and G50 than in CON . The change in PP was independently predicted by changes in fat-free mass in G80 and by changes in both FPP and VPP in G50 and G20 . CONCLUSION Explosive resistance training in older adults results in the ability to produce higher PP outputs with heavier loads without loss of movement velocity . Moderate- to high-intensity training induced a greater relative contribution of force to PP production in this cohort Background and aims : This study investigated whether high-velocity high-power training ( POW )  improved lower extremity muscle power and quality in functionally-limited elders greater than traditional slow-velocity progressive resistance training ( STR ) . Methods : Fifty-seven community-dwelling older adults aged 74.2±7 ( range 65–94 yrs ) , Short Physical Performance Battery score 7.7±1.4 , were r and omized to either POW ( n=23 ) ( 12 females ) , STR ( n=22 ) ( 13 females ) or a control group of lower extremity stretching ( CON ) ( n=12 ) ( 6 females ) . Training was performed three times per week for 12 weeks and subjects completed three sets of double leg press and knee extension exercises at 70 % of the one repetition maximum ( 1RM ) . Outcome measures included 1RM strength and peak power ( PP ) . Total leg lean mass was determined using dual-energy X-ray absorptiometry to estimate specific strength and specific PP . Results : During training , power output was consistently higher in POW compared to STR for knee extension ( ∼2.3-fold ) and leg press ( ∼2.8-fold ) exercises ( p<0.01 ) . Despite this , PP and specific PP of the knee extensors increased similarly from baseline in POW and STR compared to CON ( p<0.01 ) , and no significant time-group interaction occurred for PP of the leg extensors . However , gains in leg press specific PP were significantly greater in POW compared to both STR and CON ( p<0.05 ) . Total leg lean mass did not change within any group . Conclusions : A short-term intervention of high-velocity power training and traditional slow-velocity progressive resistance training yielded similar increases of lower extremity power in the mobility-impaired elderly . Neuromuscular adaptations to power training , rather than skeletal muscle hypertrophy , may have facilitated the improvements in muscle quality . Additional studies are warranted to test the efficacy of power training in older individuals with compromised physical functioning OBJECTIVES To evaluate a dynamic form of weighted vest exercise suitable for home use and design ed to enhance muscle power , balance , and mobility . DESIGN A single-blind , r and omized , controlled trial . SETTING Outpatient exercise research facility situated within an academic long-term care center . PARTICIPANTS Twenty-one community-dwelling women aged 70 and older with a Short Physical Performance Battery ( SPPB ) score between 4 and 10 ( out of 12 ) . INTERVENTIONS Subjects were r and omized into a progressive resistance-training program using weighted vests for resistance with exercises design ed to be specific to mobility tasks and have a component performed at the fastest possible velocity ( Increased Velocity Exercise Specific to Task ( InVEST ) , n=11 ) or a control exercise group ( control , n=10 ) , which performed slow-velocity , low-resistance exercise . Both groups exercised three times a week for 12 weeks . MEASUREMENTS Changes in muscle power , balance , and physical performance were compared . RESULTS In comparison to control group , InVEST group manifested significant improvements ( P<.05 ) in leg power across measurements obtained at 75 % to 90 % of the one-repetition maximum . Both groups demonstrated significant improvements in chair st and and SPPB score from baseline , and the InVEST group showed significant improvements in gait speed and chair st and from baseline ( P<.05 ) . InVEST produced significantly greater changes in chair st and time than control ( P<.05 ) . CONCLUSION InVEST training appears be an effective means of enhancing leg power and chair rise in this population and is worthy of further investigation as a means of enhancing balance and mobility Cycling on a mechanically braked cycle ergometer was used as a novel approach to compare the effects of three different 16-wk resistance-training programs on isometric force , power output , and selected functional abilities in 31 healthy 65- to 74-yr-old women . Training was conducted three times per week . During each session , individuals of the speed group performed 8 sets of 16 pedal revolutions at 40 % of the maximal resistance to complete two revolutions ( 2 RM ) ; strength group performed 8 sets of 8 revolutions at 80 % of 2 RM ; and combination group performed 4 sets of 16 revolutions at 40 % and 4 sets of 8 revolutions at 80 % of 2 RM . During each set , all participants were required to pedal as fast as possible with a 2-min interval between sets . All training groups significantly increased force , power , and functional abilities ( maximal treadmill walking speed , vertical jumping , and box stepping ) at week 8 ( in the range from 6.5 to 20.8 % ) with no further improvement at week 16 ( except maximal treadmill walking speed ) , but no significant differences were observed between the three groups . The novel approach to performing both low- and high-resistance training , based on the use of a cycle ergometer , has been shown to be effective in improving strength , power , and functional abilities in a group of healthy women . Even fit older women can still improve in functional abilities . Interestingly , the " high-speed " and " low-speed " programs induced an increase in both power and strength of similar magnitude Background Although progressive resistance strength training ( ST ) has been found to improve various measures of physical functioning in older adults , the benefit to quality of life is unclear . Additionally , recent evidence suggests that high velocity power training ( PT ) may be more beneficial for physical functioning than ST , but it is not known whether this type of training impacts quality of life . The purpose of this study was to compare changes in multiple measures of quality of life result ing from ST vs. PT in older adults . A no exercise group was also included as control comparison condition . Methods Forty-five older adults ( M age = 74.8 years ; SD = 5.7 ) were r and omly assigned to either a ) PT , b ) ST , or c ) control group ( no exercise ) . Measures of self-efficacy ( SE ) , satisfaction with physical function ( SPF ) , and the Satisfaction with Life Scale ( SWL ) were assessed at baseline and following training . The resistance training conditions met 3 times per week for 12 weeks at an intensity of 70 % 1 repetition maximum . Results A series of ANCOVA 's comparing between group differences in change and controlling for baseline values revealed significant group differences in all three measures : SE ( F(2,31 ) = 9.77 ; p < .001 ) ; SPF ( F(2,32 ) = 3.36 ; p = .047 ) ; SWL ( F(2,31 ) = 4.76 ; p = .016 ) . Follow up analyses indicated that the PT group reported significantly more change in SE , SPF , and SWL than the control group whereas the ST group reported greater change than the control group only in SE . Conclusion These pilot data indicate that high velocity power training may influence multiple levels of quality of life over and above the benefits gained through traditional strength training BACKGROUND Loss of muscle power due to normal aging has greater functional impact than loss of strength alone . The present study compared two resistance training programs , one aim ed at enhancing muscle power and one at increasing muscle strength , on muscle function and functional performance in older adults . METHODS Sixty-seven healthy , independent older adults ( 65 - 84 years ) were r and omized to a high-velocity varied resistance ( HV ) , constant resistance ( ST ) , or nontraining control ( CO ) group . Participants trained twice weekly for 24 weeks using six exercises .  Dynamic and isometric muscle strength , muscle power , movement velocity , muscle endurance , and a battery of functional performance tasks were assessed . Secondary outcomes included body composition , quality of life , and balance confidence . RESULTS Muscle strength increased significantly ( p < .001 ) and similarly in the training groups compared to controls ( HV , 51.0 + /- 9.0 % ; ST , 48.3 + /- 6.8 % ; CO , 1.2 + /- 5.1 % ) . Peak muscle power also increased with training ( p < .05 ) , with no difference between training groups . The change in peak power was 50.5 + /- 4.1 % , 33.8 + /- 3.8 % , and -2.5 + /- 3.9 % in the HV , ST , and CO groups , respectively . Training also improved selected functional performance tasks in the HV and ST groups compared to controls ( p < .05 ) , and the HV group reported improved quality of life ( p = .018 ) . CONCLUSION Muscle power and muscle strength improved similarly using either resistance training protocol , and these 
    Output:
    
agent
power training is feasible for elderly persons and has a small advantage over strength training for functional outcomes .
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Periodization is the most effective approach to resistance training ; however , optimal cycle lengths for older persons are not known . This study examined the duration s of performance increments , plateaus , and decrements in women , ages 61 - 75 yr , over 9 wk of isokinetic training .  After a 2-wk adaptation cycle , older women trained for either power ( PWR ; 4.73 rad/s ; n = 9 ) or strength ( STR ; 1.05 rad/s ; n = 8) , 3 days/wk with a 1-day recovery between sessions . Repetitions were initially selected to equilibrate work volume between groups . Average power ( AP ) , peak torque ( PT ) , and total work ( TW ) curves were analyzed using forward and backward stepwise regression to ascertain inflections and plateaus . PWR training produced the highest AP , whereas STR produced the highest PT . TW was similar between groups . The AP curves of the PWR group initially showed a steep positive slope and then plateaued during week 3 . The right leg plateau lasted throughout training , whereas the left leg showed another positive inflection during weeks 7 and 8 . PWR group TW curves showed positive slopes throughout training . STR group PT curves for both legs showed initial positive slopes peaking between weeks 3 and 4 and declining thereafter . The TW curves for both legs showed slight negative slopes across the first 2 wk , steep positive slopes during weeks 3 - 6 , and a final plateau . Because improvements plateau early during PWR and STR training , isokinetic training prescriptions for optimizing strength and power improvements in older persons should use cycles of 3 - 4 wk to maximize gains BACKGROUND Muscle power ( force x velocity ) recedes at a faster rate than strength with age and may also be a stronger predictor of fall risk and functional decline . The optimal training paradigm for improving muscle power in older adults is not known , although some literature suggests high velocity , low load training is optimal in young adults . METHODS One hundred twelve healthy older adults ( 69 + /- 6 years ) were r and omly assigned to either explosive resistance training at 20 % ( G20 ) , 50 % ( G50 ) , or 80 % ( G80 ) one repetition maximum ( 1RM ) for 8 - 12 weeks or to a nontraining control group ( CON ) . Participants trained twice per week ( five exercises ; three sets of eight rapidly concentric and slow eccentric repetitions ) using pneumatic resistance machines . Repeated- measures analysis of variance and covariance ( ANOVA and ANCOVA ) were used to determine the effects of training . RESULTS Average peak power increased significantly and similarly in G80 ( 14 + /- 8 % ) , G50 ( 15 + /- 9 % ) , and G20 ( 14 + /- 6 % ) compared to CON ( 3 + /- 6 % ) ( p < .0001 ) . By contrast , a positive dose-response relationship with training intensity was observed for relative changes in average strength ( r = .40 , p = .0009 ) and endurance ( r = .43 , p = .0005 ) . Average strength increased in G80 ( 20 + /- 7 % ) , G50 ( 16 + /- 7 % ) , and G20 ( 13 + /- 7 % ) compared to CON ( 4 + /- 4 % ) ( p < .0001 ) . Average muscle endurance increased in G80 ( 185 + /- 126 % , p < .0001 ) , G50 ( 103 + /- 75 % , p = .0004 ) , and G20 ( 82 + /- 57 % , p = .0078 ) compared to CON ( 28 + /- 29 % ) . CONCLUSION Peak muscle power may be improved similarly using light , moderate , or heavy resistances , whereas there is a dose-response relationship between training intensity and muscle strength and endurance changes . Therefore , using heavy loads during explosive resistance training may be the most effective strategy to achieve simultaneous improvements in muscle strength , power , and endurance in older adults OBJECTIVE To determine the effect of training intensity on the contributions of force and velocity to improvements in peak power ( PP ) after explosive resistance training in older adults . METHODS 112 healthy older adults ( 69 + /- 6 yr ) were r and omized to explosive resistance training at 20 % ( G20 ) , 50 % ( G50 ) , or 80 % ( G80 ) maximal strength ( 1-repetition maximum ) for 8 - 12 wk ( twice weekly , 5 exercises , 3 sets of 8 explosive concentric/slow eccentric repetitions ) using pneumatic resistance machines or a nontraining control group ( CON ) . RESULTS Force at peak power ( FPP ) increased significantly and similarly among training groups compared with CON . Velocity at peak power ( VPP ) did not improve significantly and remained similar between all groups . Force contributed significantly more to PP production in G80 and G50 than in CON . The change in PP was independently predicted by changes in fat-free mass in G80 and by changes in both FPP and VPP in G50 and G20 . CONCLUSION Explosive resistance training in older adults results in the ability to produce higher PP outputs with heavier loads without loss of movement velocity . Moderate- to high-intensity training induced a greater relative contribution of force to PP production in this cohort Background and aims : This study investigated whether high-velocity high-power training ( POW )  improved lower extremity muscle power and quality in functionally-limited elders greater than traditional slow-velocity progressive resistance training ( STR ) . Methods : Fifty-seven community-dwelling older adults aged 74.2±7 ( range 65–94 yrs ) , Short Physical Performance Battery score 7.7±1.4 , were r and omized to either POW ( n=23 ) ( 12 females ) , STR ( n=22 ) ( 13 females ) or a control group of lower extremity stretching ( CON ) ( n=12 ) ( 6 females ) . Training was performed three times per week for 12 weeks and subjects completed three sets of double leg press and knee extension exercises at 70 % of the one repetition maximum ( 1RM ) . Outcome measures included 1RM strength and peak power ( PP ) . Total leg lean mass was determined using dual-energy X-ray absorptiometry to estimate specific strength and specific PP . Results : During training , power output was consistently higher in POW compared to STR for knee extension ( ∼2.3-fold ) and leg press ( ∼2.8-fold ) exercises ( p<0.01 ) . Despite this , PP and specific PP of the knee extensors increased similarly from baseline in POW and STR compared to CON ( p<0.01 ) , and no significant time-group interaction occurred for PP of the leg extensors . However , gains in leg press specific PP were significantly greater in POW compared to both STR and CON ( p<0.05 ) . Total leg lean mass did not change within any group . Conclusions : A short-term intervention of high-velocity power training and traditional slow-velocity progressive resistance training yielded similar increases of lower extremity power in the mobility-impaired elderly . Neuromuscular adaptations to power training , rather than skeletal muscle hypertrophy , may have facilitated the improvements in muscle quality . Additional studies are warranted to test the efficacy of power training in older individuals with compromised physical functioning OBJECTIVES To evaluate a dynamic form of weighted vest exercise suitable for home use and design ed to enhance muscle power , balance , and mobility . DESIGN A single-blind , r and omized , controlled trial . SETTING Outpatient exercise research facility situated within an academic long-term care center . PARTICIPANTS Twenty-one community-dwelling women aged 70 and older with a Short Physical Performance Battery ( SPPB ) score between 4 and 10 ( out of 12 ) . INTERVENTIONS Subjects were r and omized into a progressive resistance-training program using weighted vests for resistance with exercises design ed to be specific to mobility tasks and have a component performed at the fastest possible velocity ( Increased Velocity Exercise Specific to Task ( InVEST ) , n=11 ) or a control exercise group ( control , n=10 ) , which performed slow-velocity , low-resistance exercise . Both groups exercised three times a week for 12 weeks . MEASUREMENTS Changes in muscle power , balance , and physical performance were compared . RESULTS In comparison to control group , InVEST group manifested significant improvements ( P<.05 ) in leg power across measurements obtained at 75 % to 90 % of the one-repetition maximum . Both groups demonstrated significant improvements in chair st and and SPPB score from baseline , and the InVEST group showed significant improvements in gait speed and chair st and from baseline ( P<.05 ) . InVEST produced significantly greater changes in chair st and time than control ( P<.05 ) . CONCLUSION InVEST training appears be an effective means of enhancing leg power and chair rise in this population and is worthy of further investigation as a means of enhancing balance and mobility Cycling on a mechanically braked cycle ergometer was used as a novel approach to compare the effects of three different 16-wk resistance-training programs on isometric force , power output , and selected functional abilities in 31 healthy 65- to 74-yr-old women . Training was conducted three times per week . During each session , individuals of the speed group performed 8 sets of 16 pedal revolutions at 40 % of the maximal resistance to complete two revolutions ( 2 RM ) ; strength group performed 8 sets of 8 revolutions at 80 % of 2 RM ; and combination group performed 4 sets of 16 revolutions at 40 % and 4 sets of 8 revolutions at 80 % of 2 RM . During each set , all participants were required to pedal as fast as possible with a 2-min interval between sets . All training groups significantly increased force , power , and functional abilities ( maximal treadmill walking speed , vertical jumping , and box stepping ) at week 8 ( in the range from 6.5 to 20.8 % ) with no further improvement at week 16 ( except maximal treadmill walking speed ) , but no significant differences were observed between the three groups . The novel approach to performing both low- and high-resistance training , based on the use of a cycle ergometer , has been shown to be effective in improving strength , power , and functional abilities in a group of healthy women . Even fit older women can still improve in functional abilities . Interestingly , the " high-speed " and " low-speed " programs induced an increase in both power and strength of similar magnitude Background Although progressive resistance strength training ( ST ) has been found to improve various measures of physical functioning in older adults , the benefit to quality of life is unclear . Additionally , recent evidence suggests that high velocity power training ( PT ) may be more beneficial for physical functioning than ST , but it is not known whether this type of training impacts quality of life . The purpose of this study was to compare changes in multiple measures of quality of life result ing from ST vs. PT in older adults . A no exercise group was also included as control comparison condition . Methods Forty-five older adults ( M age = 74.8 years ; SD = 5.7 ) were r and omly assigned to either a ) PT , b ) ST , or c ) control group ( no exercise ) . Measures of self-efficacy ( SE ) , satisfaction with physical function ( SPF ) , and the Satisfaction with Life Scale ( SWL ) were assessed at baseline and following training . The resistance training conditions met 3 times per week for 12 weeks at an intensity of 70 % 1 repetition maximum . Results A series of ANCOVA 's comparing between group differences in change and controlling for baseline values revealed significant group differences in all three measures : SE ( F(2,31 ) = 9.77 ; p < .001 ) ; SPF ( F(2,32 ) = 3.36 ; p = .047 ) ; SWL ( F(2,31 ) = 4.76 ; p = .016 ) . Follow up analyses indicated that the PT group reported significantly more change in SE , SPF , and SWL than the control group whereas the ST group reported greater change than the control group only in SE . Conclusion These pilot data indicate that high velocity power training may influence multiple levels of quality of life over and above the benefits gained through traditional strength training BACKGROUND Loss of muscle power due to normal aging has greater functional impact than loss of strength alone . The present study compared two resistance training programs , one aim ed at enhancing muscle power and one at increasing muscle strength , on muscle function and functional performance in older adults . METHODS Sixty-seven healthy , independent older adults ( 65 - 84 years ) were r and omized to a high-velocity varied resistance ( HV ) , constant resistance ( ST ) , or nontraining control ( CO ) group . Participants trained twice weekly for 24 weeks using six exercises .  Dynamic and isometric muscle strength , muscle power , movement velocity , muscle endurance , and a battery of functional performance tasks were assessed . Secondary outcomes included body composition , quality of life , and balance confidence . RESULTS Muscle strength increased significantly ( p < .001 ) and similarly in the training groups compared to controls ( HV , 51.0 + /- 9.0 % ; ST , 48.3 + /- 6.8 % ; CO , 1.2 + /- 5.1 % ) . Peak muscle power also increased with training ( p < .05 ) , with no difference between training groups . The change in peak power was 50.5 + /- 4.1 % , 33.8 + /- 3.8 % , and -2.5 + /- 3.9 % in the HV , ST , and CO groups , respectively . Training also improved selected functional performance tasks in the HV and ST groups compared to controls ( p < .05 ) , and the HV group reported improved quality of life ( p = .018 ) . CONCLUSION Muscle power and muscle strength improved similarly using either resistance training protocol , and these 
    Output:
    