***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: OBJECTIVE To determine the effect of frequency of resistive training on gain in muscle strength and neuromuscular performance in healthy older adults . DESIGN A r and omized controlled trial with subjects assigned either to high-intensity resistance training 1 ( EX1 ) , 2 ( EX2 ) , or 3 ( EX3 ) days per week for 24 weeks or to a control group ( CO ) . SETTING An exercise facility at an academic medical center . SUBJECTS Forty-six community-dwelling healthy men ( n = 29 ) and women ( n = 17 ) aged 65 to 79 years . INTERVENTION Progressive resistance training consisting of three sets of eight exercises targeting major muscle groups of the upper and lower body , at 80 % of one-repetition maximum ( 1-RM ) for eight repetitions , either 1 , 2 , or 3 days per week . MEASURES Dynamic muscle strength ( 1-RM ) using isotonic equipment every 4 weeks , bone mineral density and body composition by dual energy X-ray absorptiometry ( DXA ) , and neuromuscular performance by timed chair rise and 6-meter backward t and em walk . RESULTS For each of the eight exercises , muscle strength increased in the exercise groups relative to CO ( P < .01 ) , with no difference among EX1 , EX2 and EX3 groups at any measurement interval . Percent change averaged 3.9 + /- 2.4 ( CO ) , 37.0 + /- 15.2 ( EX1 ) , 41.9 + /- 18.2 ( EX2 ) , and 39.7 + /- 9.8 ( EX3 ) . The time to rise successfully from the chair 5 times decreased significantly ( P < .01 ) at 24 weeks , whereas improvement in the 6-meter backward t and em walk approached significance ( P = .10 ) in the three exercise groups compared with CO . Changes in chair rise ability were correlated to percent changes in quadriceps strength ( r = -0.40 , P < .01 ) and lean mass ( r = -0.40 , P < .01 ) . CONCLUSIONS A program of once or twice weekly resistance exercise achieves muscle strength gains similar to 3 days per week training in older adults and is associated with improved neuromuscular performance . Such improvement could potentially reduce the risk of falls and fracture in older adults PURPOSE This investigation examined the effect of 6 months of high- or low-intensity resistance exercise ( REX ) on bone mineral density ( BMD ) and biochemical markers of bone turnover in adults aged 60 - 83 yr . METHODS Sixty-two men and women ( 68.4 + /- 6 yr ) were stratified for strength and r and omly assigned to a control ( CON , N = 16 ) , low-intensity ( LEX , N = 24 ) , or high-intensity ( HEX , N = 22 ) group . Subjects participated in 6 months of progressive REX training . Subjects trained at either 50 % of their one repetition maximum ( 1-RM ) for 13 repetitions ( LEX ) or 80 % of 1-RM for 8 repetitions ( HEX ) 3 times x wk(-1 ) for 24 wk . One set each of 12 exercises was performed . 1-RM was measured for eight exercises . BMD was measured for total body , femoral neck , and lumbar spine by dual energy x-ray absorptiometry ( DXA ) . Serum levels of bone-specific alkaline phosphatase ( BAP ) , osteocalcin ( OC ) , and pyridinoline cross-links ( PYD ) were measured . RESULTS 1-RM significantly increased for all exercises tested for both the HEX and LEX groups ( P < and = 0.050 ) . The percent increases in total strength ( sum of all eight 1-RMs ) were 17.2 % and 17.8 % for the LEX and HEX groups , respectively . Bone mineral density ( BMD ) of the femoral neck significantly ( P < 0.05 ) increased by 1.96 % for the HEX group . No other significant changes for BMD were found . OC increased by 25.1 % and 39.0 % for the LEX and HEX groups , respectively ( P < 0.05 ) . BAP significantly ( P < 0.05 ) increased 7.1 % for the HEX group . CONCLUSION These data indicate high-intensity REX training was successful for improving BMD of the femoral neck in healthy elderly subjects . Also , these data suggest REX increased bone turnover , which over time may lead to further changes in BMD This study compared the effects of two exercise training programs , 11 months in duration , on bone mineral density ( BMD ) in older , sedentary women . Thirty-nine women , aged 60 - 74 years , were assigned to the following groups : ( a ) a group that performed exercises that introduced stress to the skeleton through ground-reaction forces ( GRF ) ( i.e. , walking , jogging , stairs ) ; ( b ) a group that performed exercises that introduced stress to the skeleton through joint-reaction forces ( JRF ) ( i.e. , weight lifting , rowing ) ; or ( c ) a no-exercise control group .  BMD of the whole body , lumbar spine , proximal femur , and distal forearm was assessed five times at approximately 3-month intervals . The GRF and JRF exercise programs result ed in significant and similar increases in BMD of the whole body ( 2.0 + /- 0.8 % and 1.6 + /- 0.4 % , respectively ) , lumbar spine ( 1.8 + /- 0.7 % and 1.5 + /- 0.5 % , respectively ) , and Ward 's triangle region of the proximal femur ( 6.1 + /- 1.5 % and 5.1 + /- 2.1 % , respectively ) . There was a significant in BMD of the femoral neck only in response to the GRF exercise program ( GRF , 3.5 + /- 0.8 % ; JRF , -0.2 + /- 0.7 % ) . There were no significant changes in BMD in control subjects . Among all exercisers , there was a significant inverse ( r = -0.52 , p < 0.01 ) relationship between increases in whole body BMD and reductions in fat mass , suggesting a dose response effect of exercise on bone mass . Although femoral neck BMD was responsive only to the GRF exercise program , some adaptations ( i.e. , increase in lean body mass and strength ) that were specific to the JRF exercise program may be important in preventing osteoporotic fractures by reducing the risk for falls . It remains to be determined whether all of these benefits can be gained through a training program that combines the different types of exercises employed in this study PURPOSE The purpose of this study was to compare the effects of a high-load ( 80 % , 1-repetition maximum ( RM ) , 8 reps ) and a high-repetition ( 40 % , 1-RM , 16 reps ) resistance training protocol on muscular strength and bone mineral density ( BMD ) in early postmenopausal , estrogen-deficient women . The 6-month programs were matched initially for training volume ( 3 sets , 3 d x wk(-1 ) ) for 12 exercises selected to specifically load the spine and hip . METHODS Subjects included 25 women ( 41 - 60 yr ) who were matched by spine BMD then r and omly assigned to either the high-load ( HL , N = 10 ) , high-repetition ( HR , N = 7 ) , or control ( C , N = 8) groups . Dietary calcium intakes were supplemented to approximately 1500 mg x d(-1 ) . Total body , spine , and hip BMD ( DXA , Lunar Model DPX-IQ ) , upper and lower body muscular strength , and biochemical markers of bone turnover were measured at baseline and after 6 months of training . RESULTS There were no group differences in the baseline measures . Both training groups showed similar increases in biceps ( 20 % ) and rectus femoris ( 28 - 33 % ) cross-sectional areas , in lower body strength ( approximately 30 % ) and in hip strength ( 37 - 40 % ) . HL showed greater improvements in upper body strength ( HL 25 % , HR 16 % ) . Neither training group experienced significant increases in spine or hip BMD , although the HL total body BMD tended to decrease ( -1.1%+/-0.4 , P = 0.054 ) after training . Osteocalcin tended to increase ( P = 0.08 ) in all groups after training , and the % change in osteocalcin was positively related to % changes in the total hip ( r = 0.41 , P = 0.048 ) and the trochanter ( r = 0.42 , P = 0.04 ) BMD . CONCLUSION The high-load and high-repetition resistance training protocol s were both effective in improving muscular strength and size in postmenopausal women , indicating low-intensity resistance training can be beneficial for the muscular fitness in women for whom high-intensity exercise is contraindicated OBJECTIVE To determine how multiple risk factors for osteoporotic fractures could be modified by high-intensity strength training exercises in postmenopausal women . DESIGN R and omized controlled trial of 1-year duration . SETTING Exercise laboratory at Tufts University , Boston , Mass. POPULATION Forty postmenopausal white women , 50 to 70 years of age , participated in the study ; 39 women completed the study . The subjects were sedentary and estrogen-deplete . INTERVENTIONS High-intensity strength training exercises 2 days per week using five different exercises ( n = 20 ) vs untreated controls ( n = 19 ) . MAIN OUTCOME MEASURES Dual energy x-ray absorptiometry for bone status , one repetition maximum for muscle strength , 24-hour urinary creatinine for muscle mass , and backward t and em walk for dynamic balance . RESULTS Femoral neck bone mineral density and lumbar spine bone mineral density increased by 0.005 + /- 0.039 g/cm2 ( 0.9 % + /- 4.5 % ) ( mean + /- SD ) and 0.009 + /- 0.033 g/cm2 ( 1.0 % + /- 3.6 % ) , respectively , in the strength-trained women and decreased by -0.022 + /- 0.035 g/cm2 ( -2.5 % + /- 3.8 % ) and -0.019 + /- 0.035 g/cm2 ( -1.8 % + /- 3.5 % ) , respectively , in the controls ( P = .02 and .04 ) . Total body bone mineral content was preserved in the strength-trained women ( + 2.0 + /- 68 g ; 0.0 % + /- 3.0 % ) and tended to decrease in the controls ( -33 + 77 g ; -1.2 % + /- 3.4 % , P = .12 ) . Muscle mass , muscle strength , and dynamic balance increased in the strength-trained women and decreased in the controls ( P = .03 to < .001 ) . CONCLUSIONS High-intensity strength training exercises are an effective and feasible means to preserve bone density while improving muscle mass , strength , and balance in postmenopausal women The purpose of this study was to determine the effects of a 12-month resistance training program , of two different intensities , on bone mineral density ( BMD ) in healthy , older women . Twenty-six Caucasian women ( aged 65 - 79 years ) completed the study . Subjects were r and omly assigned to one of three groups : high-intensity ( HI ; n = 8) , low-intensity ( LI ; n = 7 ) , and control ( CON ; n = 11 ) . The active groups performed 10 exercises , 3 days/week under supervision . Exercise intensity was maintained at 80 % of one-repetition maximum ( 1-RM ) for the HI groups , and at 40 % 1-RM for the LI group . The volume of work was maintained constant between the two groups by assigning the LI group twice as many repetitions for each exercise . Maximal muscular strength and BMD of the lumbar spine and total hip were measured at baseline and at 12 months . Strength was evaluated using the 1-RM method , and BMD was determined by dual-energy X-ray absorptiometry . Exercise session attendance was similar for the two groups ( 81.0 % HI ; 76.8 % LI ) . Muscular strength improved in the exercisers compared with the CON group ( p < or = 0.05 ) . Percentage change in lumbar spine BMD was 0.7 + /- 1.9 % , 0.5 + /- 2.4 % , and -0.1 + /- 2.3 % for the HI , LI , and CON groups , respectively . Percentage change in total hip BMD was 0.8 + /- 2.3 % ( HI ) , 1.0 + /- 1.7 % ( LI ) , and 0.9 + /- 1.3 % ( CON ) . Group differences in BMD change were not significant ( p > 0.05 ) . These findings suggest that high-intensity and low-intensity resistance training regimens effectively increase muscular strength , but not lumbar spine or total hip BMD , in healthy , older women The separate and combined effects of weight-bearing exercise and hormone replacement therapy ( HRT ) on bone mineral density ( BMD ) were studied in 32 women , 60 to 72 years of age .  H 
    Output:
    
Subgroup analyses showed more anatomical variability of BMD responses to resistance training according to participants ’ hormone therapy use .
Conclusions These findings are relevant to the nonpharmacological treatment of postmenopausal bone loss