***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: Creatine is an ergogenic aid used in individual and team sports . The aim of this study is to analyze the effect of monohydrate creatine supplementation on physical performance during 6 consecutive maximal speed 60 meter races , and the changes induced in some characteristic biochemical and ventilatory parameters . The study was carried out on nineteen healthy and physically active male volunteers , and r and omly distributed into two groups : Group C received a supplement of creatine monohydrate ( 20g/day for 5 days ) and group P received placebo . Tests were performed before and after supplementation . No significant changes were observed in weight or body water measured by bioimpedance or the sum of 7 skinfold or performance during the 6- meter races . Group C showed a statistically significant increase in plasma creatinine from 69.8±12.4 to 89.3±12.4 μmol·L−1 ( p<0.05 ) . In group C in the second control day ( after creatine  supplementation ) , expiratory volume VE , O2 uptake and CO2 production were lower after 2 minutes of active recovery period . These results indicate that creatine monohydrate supplementation does not appear to improve the performance in 6 consecutive 60 meter repeated races but may modify ventilatory dynamics during the recovery after maximal effort . ResumenLa creatina se considera una ayuda ergogénica , siendo utilizada en deportes individuales y de equipo . Se ha analizado el efecto de la ingesta de monohidrato de creatina sobre el rendimiento obtenido en 6 carreras máximas consecutivas de 60 metros y algunos parámetros bioquímicos o ventilatorios . Diecinueve varones sanos , voluntarios , físicamente activos se distribuyeron de manera aleatoria en dos grupos : Grupo C , que recibió un suplemento de monohidrato de creatina ( 20 g/día durante 5 días ) y grupo P , que recibió un placebo . Los tests se realizaron antes y después de recibir el respectivo suplemento . No se observaron diferencias significativas en el peso corporal , proporción hídrica medida por bioimpedancia , el sumatorio de 7 pliegues cutáneos ni en el rendimiento en las carreras de 60 metros tras la ingesta de monohidrato de creatina o de placebo . El grupo C mostró un aumento estadísticamente significativo en la concentración plasmática de creatinina pas and o de 69,8±12,4 a 89,3±12,4 μmol·L−1 ( p<0,05 ) . En el grupo C , en la prueba posterior a la ingesta de monohidrato de creatina , tras un periodo de dos minutos de recuperación activa , se observó un menor volumen espiratorio , VE , consumo de O2 y producción de CO2 . Los result ados indican que el suplemento de monohidrato de creatina no parece aumentar el rendimiento en 6 carreras máximas repetidas de 60 metros , pero podría modificar la dinámica ventilatoria durante la recuperación tras un esfuerzo máximo Creatine monohydrate ( CrH2O ) supplementation has been demonstrated to increase skeletal muscle power output in men . However , its effect upon women is not as clearly defined . This study investigated the effect of oral creatine supplementation upon muscle function , thigh circumference , and body weight in women . Twenty-two consenting college-age women were assigned to 1 of 2 groups matched for dietary and exercise habits , phase of menstrual cycle , and fat-free mass ( FFM ) . After familiarization with testing procedures , pretrial measures of muscle function ( 5 repetitions 60 deg x s(-1 ) and 50 repetitions 180 deg x s(-1 ) were conducted during maximal voluntary concentric contraction of the preferred quadriceps muscle using an isokinetic dynamometer . Subjects then ingested 0.5 g x kg(-1 ) FFM of either CrH2O or placebo ( one fourth dosage 4 times daily ) in a double-blind design for 5 days . Resistance exercise was prohibited . After the ingestion phase was completed , all measures were repeated at the same time of day as during pretrials . Statistical analysis revealed time to peak torque in quadriceps extension decreased from pre-test values of 255 + /- 11 ms ( mean + /- SEM ) to post-test values of 223 + /- 3 ms ; average power in extension increased from 103 + /- 7 W pre-test to 112 + /- 7 W post-test ; and , during flexion , average power increased from 59 + /- 5 W pre-test to 65 + /- 5 W post-test in the creatine group as compared to controls ( p .05 ) . FFM , percent body fat , mid-quadriceps circumference , skinfold thickness of the measured thigh , and total body weight did not change for both groups between trials . We conclude that CrH2O improves muscle performance in women without significant gains in muscle volume or body weight Oral supplementation with creatine monohydrate ( Cr . H2O ) has been reported to increase muscle creatine phosphate levels . The aim of the present study was to determine the effect of such supplementation on performance of a single-effort sprint by elite swimmers . Thirty-two elite swimmers ( M = 18 , F = 14 ; age = 17 - 25 years ) from the Australian Institute of Sport were tested on two occasions , 1 week apart . Tests performed were 25-m , 50-m , and 100-m maximal effort sprints ( electronically timed with dive start , swimmers performing their best stroke ) , each with approximately 10 min active recovery . A 10-s maximal leg ergometry test was also undertaken . Swimmers were divided into two groups matched for sex , stroke/event , and sprint time over 50 m , and groups were r and omly assigned to 5 days of Cr . H2O supplementation ( 4 . day-1 x 5 g Cr . H2O + 2 g sucrose , n = 16 ) or placebo ( 4 . day-1 x 5 g Polycose + 2 g sucrose , n = 16 ) prior to the second trial . Results revealed no significant differences between the group means for sprint times or between 10-s maximal leg ergometry power and work . This study does not support the hypothesis that creatine supplementation enhances single-effort sprint ability of elite swimmers AIM The purpose of this study was to determine the effects of Cr supplementation on muscle strength and endurance of the trained females , the effect of anaerobic exercises performed before the supplementation and disappearance of the effects on the performance . METHODS Twenty-six collegiate female softball players were divided into the Cr1 , 2 , Control (Cont.)1 or 2 group , r and omly . They performed maximal 2-isometric and 30-isokinetic knee extensions at the angular velocities of 180 degrees and 60 degrees /s . Thereafter , the subjects of the Cr2 and Cont.2 groups performed resistance exercises with 10 RM and cycling with 0.01 kg x kg-1 body weight , alternately during the 1(st ) week . During the 2(nd ) week , the subjects of the Cr1 and 2 groups ingested 20 g Cr a day for 1 week . Thereafter , the subjects in the Cr2 group continued 3 g Cr ingestion a day for 2 weeks while the Cr1 group ingested the same amount of placebo during the 3(rd ) and 4(th ) weeks . The subjects of the Cont.1 , 2 groups ingested the same amount and taste of placebo during the 1(st ) to 4(th ) weeks . This study was undergone in double blind fashion . The similar measurements , to which the subjects performed the 1(st ) day , were carried out on the final day of the 2(nd ) , 3(rd ) and 4(th ) weeks . RESULTS Though maximal isometric strength did not differ in intra- and intergroups , the isokinetic peak torque in the Cr1 group was significantly decreased in the 4(th ) measurement ( p<0.01 ) . The mean torque of the 1(st ) to 10th knee contractions at 60 inverted exclamation mark /s was significantly decreased from the 2(nd ) measurement in the Cont.1 , 2 groups , compared with that in the 1(st ) measurement ( p<0.01 ) . In the Cr groups , the significant decrease was detected from the 3(rd ) in the Cr1 and in the 4(th ) measurement in the Cr2 group . The mean torque of the latter 20 contractions at 180 inverted exclamation mark /s was significantly increased in the Cr2 group ( p<0.001 ) . In the 1(st ) measurement , the mean torque in the Cr1 group was significantly higher than that in the Cr2 group ( p<0.05 ) . However , the differences between Cr1 and 2 groups were not detected from the 2(nd ) measurement . CONCLUSION Twenty g Cr supplementation a day for a week to the trained females improves not the maximal static strength and dynamic peak torque but the mean strength and endurance of repeated contractions . However , the effects on females are not so great as that ever found in males . The effects are enhanced by anaerobic exercises performed before the supplementation and would disappear in a week if the supplementation were stopped PURPOSE This investigation examined the effects of creatine ( Cr ) supplementation on intermittent high-intensity exercise activities specific to competitive soccer . METHODS On two occasions 7 d apart , 17 highly trained male soccer players performed a counter-movement jump test ( CMJT ) , a repeated sprint test ( RST ) consisting of six maximal 15-m runs with a 30-s recovery , an intermittent endurance test ( IET ) consisting of forty 15-s bouts of high-intensity running interspersed by 10-s bouts of low-intensity running , and a recovery CMJT consisting of three jumps . After the initial testing session , players were evenly and r and omly included in a CREATINE ( 5 g of Cr , four times per day for 6 d ) or a PLACEBO group ( same dosage of maltodextrins ) using a double-blind research design . RESULTS The CREATINE group 's average 5-m and 15-m times during the RST were consistently faster after the intervention ( 0.95 + /- 0.03 vs 0.97 + /- 0.02 s , P < 0.05 and 2.29 + /- 0.08 vs 2.32 + /- 0.07 s , P = 0.07 , respectively ) . Neither group showed significant changes in the CMJT or the IET . The CREATINE group 's recovery CMJT performance relative to the resting CMJT remained unchanged postsupplementation , whereas it tended to decrease in the PLACEBO group . CONCLUSION In conclusion , acute Cr supplementation favorably affected repeated sprint performance and limited the decay in jumping ability after the IET in highly trained soccer players . Intermittent endurance performance was not affected by Cr Jump height is a critical aspect of volleyball players ' blocking and attacking performance . Although previous studies demonstrated that creatine monohydrate supplementation ( CrMS ) improves jumping performance , none have yet evaluated its effect among volleyball players with proficient jumping skills . We examined the effect of 4 wk of CrMS on 1 RM spike jump ( SJ ) and repeated block jump ( BJ ) performance among 12 elite males of the Sherbrooke University volleyball team . Using a parallel , r and omized , double-blind protocol , participants were supplemented with a placebo or creatine solution for 28 d , at a dose of 20 g/d in days 1 - 4 , 10 g/d on days 5 - 6 , and 5 g/d on days 7 - 28 . Pre- and postsupplementation , subjects performed the 1 RM SJ test , followed by the repeated BJ test ( 10 series of 10 BJs ; 3 s interval between jumps ; 2 min recovery between series ) . Due to injuries ( N = 2 ) and outlier data ( N = 2 ) , results are reported for eight subjects . Following supplementation , both groups improved SJ and repeated BJ performance . The change in performance during the 1 RM SJ test and over the first two repeated BJ series was unclear between groups . For series 3 - 6 and 7 - 10 , respectively , CrMS further improved repeated BJ performance by 2.8 % ( likely beneficial change ) and 1.9 % ( possibly beneficial change ) , compared with the placebo . Percent repeated BJ decline in performance across the 10 series did not differ between groups pre- and postsupplementation . In conclusion , CrMS likely improved repeated BJ height capability without influencing the magnitude of muscular fatigue in these elite , university-level volleyball players PURPOSE To determine whether low-dose creatine and protein supplementation during resistance training ( RT ; 3 d x wk(-1 ) ; 10 wk ) in older men ( 59 - 77 yr ) is effective for improving strength and muscle mass without producing potentially cytotoxic metabolites ( formaldehyde ) . METHODS Older men were r and omized ( double-blind ) to receive 0.1 g x kg(-1 ) creatine + 0.3 g x kg(-1 ) protein ( CP ; n = 10 ) , creatine ( C ; n = 13 ) , or placebo ( PLA ; n = 12 ) on training days . Measurements before and after RT included lean tissue mass ( air-displacement plethysmography ) , muscle thickness ( ultrasound ) of elbow , knee , and ankle flexors and extensors , leg and bench press strength , and urinary indicators of cytotoxicity ( formaldehyde ) , myofibrillar protein degradation [ 3-meth 
    Output:
    
The meta-regression showed no links with characteristics of population or of supplementation , demonstrating the creatine efficacy effects , independent of all listed conditions .
Conclusion Creatine supplementation is effective in lower limb strength performance for exercise with a duration of less than 3 min , independent of population characteristic , training protocol s , and supplementary doses and duration