***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: Abstract Schoenfeld , BJ , Ratamess , NA , Peterson , MD , Contreras , B , Sonmez , GT , and Alvar , BA . Effects of different volume-equated resistance training loading strategies on muscular adaptations in well-trained men . J Strength Cond Res 28(10 ) : 2909–2918 , 2014—Regimented resistance training has been shown to promote marked increases in skeletal muscle mass . Although muscle hypertrophy can be attained through a wide range of resistance training programs , the principle of specificity , which states that adaptations are specific to the nature of the applied stimulus , dictates that some programs will promote greater hypertrophy than others . Research is lacking , however , as to the best combination of variables required to maximize hypertophic gains . The purpose of this study was to investigate muscular adaptations to a volume-equated bodybuilding-type training program vs. a powerlifting-type routine in well-trained subjects . Seventeen young men were r and omly assigned to either a hypertrophy-type resistance training group that performed 3 sets of 10 repetition maximum ( RM ) with 90 seconds rest or a strength-type resistance training ( ST ) group that performed 7 sets of 3RM with a 3-minute rest interval . After 8 weeks , no significant differences were noted in muscle thickness of the biceps brachii . Significant strength differences were found in favor of ST for the 1RM bench press , and a trend was found for greater increases in the 1RM squat . In conclusion , this study showed that both bodybuilding- and powerlifting-type training promote similar increases in muscular size , but powerlifting-type training is superior for enhancing maximal strength Objective The main purpose of the investigation reported here was to analyze the effect of resistance training ( RT ) performed at different weekly frequencies on flexibility in older women . Participants and methods Fifty-three older women ( ≥60 years old ) were r and omly assigned to perform RT either two ( n=28 ; group “ G2x ” ) , or three ( n=25 ; group “ G3x ” ) times per week . The RT program comprised eight exercises in which the participants performed one set of 10–15 repetitions maximum for a period of 12 weeks . Anthropometric , body-composition , and flexibility measurements were made at baseline and post- study . The flexibility measurements were obtained by a fleximeter . Results A significant group-by-time interaction ( P<0.01 ) was observed for frontal hip flexion , in which G3x showed a higher increase than G2x ( + 12.8 % and + 3.0 % , respectively ) . Both groups increased flexibility in cervical extension ( G2x=+19.1 % , G3x=+20.0 % ) , right hip flexion ( G2x=+14.6 % , G3x=+15.9 % ) , and left hip flexion ( G2x=+25.7 % , G3x=+19.2 % ) , with no statistical difference between groups . No statistically significant differences were noted for the increase in skeletal muscle mass between training three versus two times a week ( + 7.4 % vs + 4.4 % , respectively ) . Conclusion Twelve weeks of RT  improves the flexibility of different joint movements in older women , and the higher frequency induces greater increases for frontal hip flexion Abstract Schoenfeld , BJ , Ratamess , NA , Peterson , MD , Contreras , B , and Tiryaki-Sonmez , G. Influence of resistance training frequency on muscular adaptations in well-trained men . J Strength Cond Res 29(7 ) : 1821–1829 , 2015—The purpose of this study was to investigate the effects of training muscle groups 1 day per week using a split-body routine ( SPLIT ) vs. 3 days per week using a total-body routine ( TOTAL ) on muscular adaptations in well-trained men . Subjects were 20 male volunteers ( height = 1.76 ± 0.05 m ; body mass = 78.0 ± 10.7 kg ; age = 23.5 ± 2.9 years ) recruited from a university population . Participants were pair matched according to baseline strength and then r and omly assigned to 1 of the 2 experimental groups : a SPLIT , where multiple exercises were performed for a specific muscle group in a session with 2–3 muscle groups trained per session ( n = 10 ) or a TOTAL , where 1 exercise was performed per muscle group in a session with all muscle groups trained in each session ( n = 10 ) . Subjects were tested pre- and post study for 1 repetition maximum strength in the bench press and squat , and muscle thickness ( MT ) of forearm flexors , forearm extensors , and vastus lateralis . Results showed significantly greater increases in forearm flexor MT for TOTAL compared with SPLIT . No significant differences were noted in maximal strength measures . The findings suggest a potentially superior hypertrophic benefit to higher weekly resistance training frequencies Abstract Schoenfeld , BJ , Peterson , MD , Ogborn , D , Contreras , B , and Sonmez , GT . Effects of low- vs. high-load resistance training on muscle strength and hypertrophy in well-trained men . J Strength Cond Res 29(10 ) : 2954–2963 , 2015—The purpose of this study was to compare the effect of low- versus high-load resistance training ( RT ) on muscular adaptations in well-trained subjects . Eighteen young men experienced in RT were matched according to baseline strength and then r and omly assigned to 1 of 2 experimental groups : a low-load RT routine ( LL ) where 25–35 repetitions were performed per set per exercise ( n = 9 ) or a high-load RT routine ( HL ) where 8–12 repetitions were performed per set per exercise ( n = 9 ) . During each session , subjects in both groups performed 3 sets of 7 different exercises representing all major muscles . Training was performed 3 times per week on nonconsecutive days , for a total of 8 weeks . Both HL and LL conditions produced significant increases in thickness of the elbow flexors ( 5.3 vs. 8.6 % , respectively ) , elbow extensors ( 6.0 vs. 5.2 % , respectively ) , and quadriceps femoris ( 9.3 vs. 9.5 % , respectively ) , with no significant differences noted between groups . Improvements in back squat strength were significantly greater for HL compared with LL ( 19.6 vs. 8.8 % , respectively ) , and there was a trend for greater increases in 1 repetition maximum ( 1RM ) bench press ( 6.5 vs. 2.0 % , respectively ) . Upper body muscle endurance ( assessed by the bench press at 50 % 1RM to failure ) improved to a greater extent in LL compared with HL ( 16.6 vs. −1.2 % , respectively ) . These findings indicate that both HL and LL training to failure can elicit significant increases in muscle hypertrophy among well-trained young men ; however , HL training is superior for maximizing strength adaptations Changes in muscle mass and strength will vary , depending on the volume and frequency of training . The purpose of this study was to determine the effect of short-term equal-volume resistance training with different workout frequency on lean tissue mass and muscle strength .  Twenty-nine untrained volunteers ( 27–58 years ; 23 women , 6 men ) were assigned r and omly to 1 of 2 groups : group 1 ( n = 15 ; 12 women , 3 men ) trained 2 times per week and performed 3 sets of 10 repetitions to fatigue for 9 exercises , group 2 ( n = 14 ; 11 women , 3 men ) trained 3 times per week and performed 2 sets of 10 repetitions to fatigue for 9 exercises . Prior to and following training , whole-body lean tissue mass ( dual energy x-ray absorptiometry ) and strength ( 1 repetition maximum squat and bench press ) were measured . Both groups increased lean tissue mass ( 2.2 % ) , squat strength ( 28 % ) , and bench press strength ( 22–30 % ) with training ( p < 0.05 ) , with no other differences . These results suggest that the volume of resistance training may be more important than frequency in developing muscle mass and strength in men and women initiating a resistance training program The purpose of this investigation was to study a high-intensity resistance exercise overtraining protocol result ing in muscular strength decrements .  Seventeen weight-trained males were divided into an  overtraining group ( OT ; N = 11 ; mean + /- SE , age = 22.0 + /- 0.9 yr , )  that exercised on a squat machine daily for 2 wk with 100 % of 1 repetition maximum ( RM ) relative intensity , and a control group ( CON ; N = 6 ; age = 23.7 + /- 2.4 yr )  that exercised 1 d.wk-1 with low intensity ( 50 % 1 RM ) . Test batteries were conducted at the beginning ( test 1 ) , after 1 wk ( test 2 ) , and after 2 wk ( test 3 ) of the study . One RM performance significantly decreased from test 1 to test 3 ( P < 0.05 ) for the OT group ( mean = -12.2 + /- 3.8 kg ) , but not the CON group ( mean = -1.1 + /- 0.8 kg ) . Isokinetic and stimulated isometric muscle force significantly decreased for the OT group compared with the CON group by test 3 . The primary site of maladaptation appeared to be in the periphery as indicated by changes in stimulated force , circulating CK activity , and exercise-induced lactate responses . This protocol produced a significant decrease in 1 RM performance , thus providing a model for the study of short-term , high-intensity resistance exercise overtraining The purpose of this study was to compare different split resistance training routines on body composition and muscular strength in elite bodybuilders . Ten male bodybuilders ( 26.7 ± 2.7 years , 85.3 ± 10.4 kg ) were r and omly assigned into one of two resistance training groups : 4 and 6 times per week ( G4 × and G6 × , respectively ) , in which the individuals trained for 4 weeks , 4 sets for each exercise performing 6 - 12 repetitions maximum ( RM ) in a pyramid fashion  . Body composition was assessed by dual energy X-ray absorptiometry , muscle strength was evaluated by 1RM bench-press testing . The food intake was planned by nutritionists and offered individually throughout the duration of the experiment . Significant increases ( p < .05 ) in fat-free mass ( G4 × = + 4.2 % , G6 × = + 3.5 % ) and muscular strength ( G4 × = + 8.4 % , G6 × = + 11.4 % ) with no group by time interaction were observed . We conclude that 4 and 6 weekly sessions frequencies of resistance training promote similar increases in fat-free mass and muscular strength in elite bodybuilders 
    Output:
    
Conclusions When comparing studies that investigated training muscle groups between 1 to 3 days per week on a volume-equated basis , the current body of evidence indicates that frequencies of training twice a week promote superior hypertrophic outcomes to once a week .