***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: The purpose of this study was to determine the effects of beta-alanine supplementation and high-intensity interval training ( HIIT ) on electromyographic fatigue threshold ( EMGFT ) and efficiency of electrical activity ( EEA ) . A total of 46 men completed four , 2-min work bouts on a cycle ergometer . Using bipolar surface electrodes , the EMG amplitude was averaged and plotted over the 2-min . The result ing slopes were used to calculate EMGFT and EEA . Following initial testing , all participants were r and omly assigned to either placebo ( PL ; n = 18 ) , beta-alanine ( BA ; n = 18 ) or control groups ( CON ; n = 10 ) . Following r and omization , participants engaged in 6 weeks of HIIT training . Significant improvements in EMGFT and EEA result ed for both training groups . In conclusion , HIIT appeared to be the primary stimulus effecting EMGFT or EEA , suggesting adaptations from HIIT may be more influential than increasing skeletal muscle carnosine levels on delaying fatigue in recreationally active men Summary .The effect of beta-alanine ( β-Ala ) alone or in combination with creatine monohydrate ( Cr ) on aerobic exercise performance is unknown . The purpose of this study was to examine the effects of 4 weeks of β-Ala and Cr supplementation on indices of endurance performance . Fifty-five men ( 24.5 ± 5.3 yrs ) participated in a double-blind , placebo-controlled study and r and omly assigned to one of 4 groups ; placebo ( PL , n = 13 ) , creatine ( Cr , n = 12 ) , beta-alanine ( β-Ala , n = 14 ) , or beta-alanine plus creatine ( CrBA , n = 16 ) . Prior to and following supplementation , participants performed a grade d exercise test on a cycle ergometer to determine VO2peak , time to exhaustion ( TTE ) , and power output , VO2 , and percent VO2peak associated with VT and LT . No significant group effects were found . However , within groups , a significant time effect was observed for CrBa on 5 of the 8 parameters measured . These data suggest that CrBA may potentially enhance endurance performance The aim of this study was to examine the effect of β-alanine supplementation on repeated sprint performance during an intermittent exercise protocol design ed to replicate games play . Sixteen elite and twenty non-elite game players performed the Loughborough Intermittent Shuttle Test ( LIST ) on two separate occasions . Trials were separated by 4 weeks of supplementation with either β-alanine ( BA ) or maltodextrin ( MD ) . There was no deterioration in sprint times from Set 1 to Set 6 of the LIST in either group prior to supplementation ( elite : P = 0.92 ; non-elite : P = 0.12 ) . Neither BA nor MD supplementation affected sprint times . Blood lactate concentrations were elevated during exercise in both groups , with no effect of supplementation . β-Alanine supplementation did not significantly improve sprint performance during the LIST . Neither group showed a performance decrement prior to supplementation , which might have masked any benefit from increased muscle buffering capacity due to β-alanine supplementation Beta-alanine may benefit short- duration , high-intensity exercise performance . The aim of this r and omized double-blind placebo-controlled study was to examine the effects of beta-alanine supplementation on aspects of muscular performance in highly trained cyclists . Sixteen highly trained cyclists ( mean ± SD ; age = 24 ± 7 yr ; mass = 70 ± 7 kg ; VO2max = 67 ± 4 ml · kg(-1 ) · min(-1 ) )  supplemented with either beta-alanine ( n = 8 , 65 mg · kg - 1BM ) or a placebo ( n = 8 ; dextrose monohydrate ) over 4 weeks . Pre- and postsupplementation cyclists performed a 4-minute maximal cycling test to measure average power and 30 reciprocal maximal isokinetic knee contractions at a fixed angular velocity of 180 ° · sec(-1 ) to measure average power/repetition , total work done ( TWD ) , and fatigue index ( % ) . Blood pH , lactate ( La- ) and bicarbonate ( HCO3- ) concentrations were measured pre- and postisokinetic testing at baseline and following the supplementation period . Beta-alanine supplementation was 44 % likely to increase average power output during the 4-minute cycling time trial when compared with the placebo , although this was not statistically significant ( p = .25 ) . Isokinetic average power/repetition was significantly increased post beta-alanine supplementation compared with placebo ( beta-alanine : 6.8 ± 9.9 W , placebo : -4.3 ± 9.5 W , p = .04 , 85 % likely benefit ) , while fatigue index was significantly reduced ( p = .03 , 95 % likely benefit ) . TWD was 89 % likely to be improved following beta-alanine supplementation ; however , this was not statistically significant ( p = .09 ) . There were no significant differences in blood pH , lactate , and HCO3- between groups ( p > .05 ) . Four weeks of beta-alanine supplementation result ed in worthwhile changes in time-trial performance and short- duration muscular force production in highly trained cyclists Background Ageing is associated with a significant reduction in skeletal muscle carnosine which has been linked with a reduction in the buffering capacity of muscle and in theory , may increase the rate of fatigue during exercise . Supplementing beta-alanine has been shown to significantly increase skeletal muscle carnosine . The purpose of this study , therefore , was to examine the effects of ninety days of beta-alanine supplementation on the physical working capacity at the fatigue threshold ( PWCFT ) in elderly men and women . Methods Using a double-blind placebo controlled design , twenty-six men ( n = 9 ) and women ( n = 17 ) ( age ± SD = 72.8 ± 11.1 yrs ) were r and omly assigned to either beta-alanine ( BA : 800 mg × 3 per day ; n = 12 ; CarnoSyn ™ ) or Placebo ( PL ; n = 14 ) group . Before ( pre ) and after ( post ) the supplementation period , participants performed a discontinuous cycle ergometry test to determine the PWCFT . Results Significant increases in PWCFT ( 28.6 % ) from pre- to post-supplementation were found for the BA treatment group ( p < 0.05 ) , but no change was observed with PL treatment . These findings suggest that ninety days of BA supplementation may increase physical working capacity by delaying the onset of neuromuscular fatigue in elderly men and women . Conclusion We suggest that BA supplementation , by improving intracellular pH control , improves muscle endurance in the elderly . This , we believe , could have importance in the prevention of falls , and the maintenance of health and independent living in elderly men and women Abstract Smith-Ryan , AE , Fukuda , DH , Stout , JR , and Kendall , KL . High-velocity intermittent running : effects of beta-alanine supplementation . J Strength Cond Res 26(10 ) : 2798–2805 , 2012—The use of & bgr;-alanine in sport is widespread . However , the effects across all sport activities are inconclusive . The purpose of this study was to evaluate the effects of & bgr;-alanine supplementation on high-intensity running performance and critical velocity ( CV ) and anaerobic running capacity ( ARC ) .  Fifty recreationally trained men were r and omly assigned , in a double-blind fashion , to a & bgr;-alanine group ( BA , 2 × 800 mg tablets , 3 times daily ; CarnoSyn ; n = 26 ) or placebo group ( PL , 2 × 800 mg maltodextrin tablets , 3 times daily ; n = 24 ) . A grade d exercise test ( GXT ) was performed to establish peak velocity ( PV ) . Three high-speed runs to exhaustion were performed at 110 , 100 , and 90 % of PV , with 15 minutes of rest between bouts . The distances achieved were plotted over the time to exhaustion ( TTE ) . Linear regression was used to determine the slope ( CV ) and y-intercept ( ARC ) of these relationships to assess aerobic and anaerobic performances , respectively . There were no significant treatment effects ( p > 0.05 ) on CV or ARC for either men or women . Additionally , no TTE effects were evident for bouts at 90–110%PV lasting 1.95–5.06 minutes . There seems to be no ergogenic effect of & bgr;-alanine supplementation on CV , ARC , or high-intensity running lasting approximately 2–5 minutes in either men or women in the current study Carnosine ( β-alanyl-l-histidine ) is found in high concentrations in skeletal muscle and chronic β-alanine ( BA ) supplementation can increase carnosine content . This placebo-controlled , double-blind study compared two different 8-week BA dosing regimens on the time course of muscle carnosine loading and 8-week washout , leading to a BA dose – response study with serial muscle carnosine assessment s throughout . Thirty-one young males were r and omized into three BA dosing groups : ( 1 ) high – low : 3.2 g BA/day for 4 weeks , followed by 1.6 g BA/day for 4 weeks ; ( 2 ) low – low : 1.6 g BA/day for 8 weeks ; and ( 3 ) placebo . Muscle carnosine in tibialis-anterior ( TA ) and gastrocnemius ( GA ) muscles was measured by 1H-MRS at weeks 0 , 2 , 4 , 8 , 12 and 16 . Flushing symptoms and blood clinical chemistry were trivial in all three groups and there were no muscle carnosine changes in the placebo group . During the first 4 weeks , the increase for high – low ( TA 2.04 mmol/kgww , GA 1.75 mmol/kgww ) was ~twofold greater than low – low ( TA 1.12 mmol/kgww , GA 0.80 mmol/kgww ) . 1.6 g BA/day significantly increased muscle carnosine within 2 weeks and induced continual rises in already augmented muscle carnosine stores ( week 4–8 , high – low regime ) . The dose – response showed a carnosine increase of 2.01 mmol/kgww per 100 g of consumed BA , which was only dependent upon the total accumulated BA consumed ( within a daily intake range of 1.6–3.2 g BA/day ) . Washout rates were gradual ( 0.18 mmol/kgww and 0.43 mmol/kgww/week ; ~2%/week ) . In summary , the absolute increase in muscle carnosine is only dependent upon the total BA consumed and is not dependent upon baseline muscle carnosine , the muscle type , or the daily amount of supplemented BA Background β-Alanine ( βA ) has been shown to improve performance during cycling . This study was the first to examine the effects of βA supplementation on the onset of blood lactate accumulation ( OBLA ) during incremental treadmill running . Methods Seventeen recreationally-active men ( mean ± SE 24.9 ± 4.7 yrs , 180.6 ± 8.9 cm , 79.25 ± 9.0 kg ) participated in this r and omized , double-blind , placebo-controlled pre/post test 2-treatment experimental design . Subjects participated in two incremental treadmill tests before and after 28 days of supplementation with either βA ( 6.0 g·d-1)(βA , n = 8) or an equivalent dose of Maltodextrin as the Placebo ( PL , n = 9 ) . Heart rate , percent heart rate maximum ( % HRmax ) , % VO2max@OBLA ( 4.0 mmol . L-1 blood lactate concentration ) and VO2max ( L.min-1 ) were determined for each treadmill test . Friedman test was used to determine within group differences ; and Mann-Whitney was used to determine between group differences for pre and post values ( p < 0.05 ) . Results The βA group experienced a significant rightward shift in HR@OBLA beats.min-1 ( p < 0.01 ) pre/post ( 161.6 ± 19.2 to 173.6 ± 9.9 ) but remained unchanged in the PL group ( 166.8 ± 15.8 to 169.6 ± 16.1 ) . The % HRmax@OBLA increased ( p < 0.05 ) pre/post in the βA group ( 83.0 % ± 9.7 to 88.6 % ± 3.7 ) versus no change in the PL group ( 86.3 ± % 4.8 to 87.9 % ± 7.2 ) . The % VO2max@OBLA increased ( p < 0.05 ) in the βA group pre/post ( 69.1 ± 11.0 to 75.6 ± 10.7 ) but remained unchanged in the PL group ( 73.3 ± 7.3 to 74.3 ± 7.3 ) . VO2max ( L.min-1 ) decreased ( p < 0.01 ) in the βA group pre 
    Output:
    
Summary / conclusions & bgr;-alanine had a significant overall effect while subgroup analyses revealed a number of modifying factors .
These data allow individuals to make informed decisions as to the likelihood of an ergogenic effect with & bgr;-alanine supplementation based on their chosen exercise modality