***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: Vibration exercise ( VbX ) has been a popular modality to enhancing physical performance , where various training methods and techniques have been employed to improve immediate and long-term sprint performance . However , the use of acute side-alternating VbX on sprint and agility performance remains unclear . Eight female athletes preformed side-alternating vibration exercise ( VbX ) and control ( no VbX ) in a cross over r and omised design that was conducted one week apart . After performing a warm-up , the athletes undertook maximal 5 m sprints and maximal reactive agility sprints ( RAT ) , this was followed by side-alternating VbX ( 26 Hz , 6 mm ) or control ( no VbX ) . Immediately following the intervention , post-sprint tests and RAT were performed . There was a significant treatment effect but there was no time effect ( pre vs. post ) or interaction effect for sprint and RAT ; however , side-alternating VbX did not compromise sprint and agility performance . Key PointsAcute VbX could be beneficial for the acceleration phase ( 1.5 m ) of a short-distance sprint . Acute VbX does not have positive influence on short-distance ( 3 m & 5 m ) sprint performance . Acute VbX does not enhance reactive agility performance Abstract We investigated the relationship between skill qualities and contact injury risk in professional rugby league players . Sixty-six professional rugby league players aged 23 ± 4 years ( mean ± s ) participated in this three-year prospect i ve study . Players underwent assessment s of  tackling proficiency , dual-task draw- and -pass proficiency  ,  reactive agility , pattern recall  , and  pattern prediction . The frailty model was applied to calculate the adjusted risk ratios of injury . When the players ' age and playing position were adjusted in the frailty model , the risk ratios showed that reactive agility was a predictor for the risk of injury . Players with reactive agility decision times of > 80 ms had a lower incidence ( relative risk = 0.68 , 95 % CI 0.47–0.98 , P = 0.04 ) of injuries than players with reactive agility decision times of ≤80 ms . Although there was no relationship between injury and the majority of skill qualities ( P = 0.47–0.93 ) , players with poor reactive agility performances ( specifically longer decision times ) had a lower risk of injury , suggesting that poor perceptual skill is protective against contact injuries in professional rugby league players . These players might inadvertently avoid the heavy collisions that result in injury , or at best result in partial contact that does not result in exposure to the full force of a tackle PURPOSE This study examined the effects of acute caffeine ingestion on agility performance and decision-making accuracy after simulated team-sport exercise . METHODS Using a r and omized , double-blinded , counterbalanced design , 10 moderately trained male team-sport athletes ingested either caffeine ( 6 mg·kg(-1 ) ) or placebo ( dextrose ) 60 min before completing an 80-min ( 4 × 20 min ) simulated team-game , intermittent running protocol . Interspersed between each exercise quarter was a reactive agility test ( RAT ) consisting of five trials where measures of total time ( TT ) , reactive agility ( RA ) time , decision time ( DT ) , movement time ( MT ) , and decision-making accuracy were obtained . RESULTS Although there were no significant differences between trials for TT ( P = 0.54 ) , RA time ( P = 0.84 ) , MT ( P = 0.89 ) , or DT ( P = 0.91 ) , caffeine ingestion result ed in consistently faster TT ( 2.3 % ) , RA time ( 3.9 % ) , MT ( 2.7 % ) , and DT ( 9.3 % ) scores compared with placebo ( significant main effect for condition for RA time , TT , DT , and MT ; P < 0.05 ) . These faster times were supported by qualitative analyses of " almost certain benefit " and large effect size ( ES ) for RA ( quarter 3 ) and " likely " to " very likely benefits " and moderate to large ES for TT ( precircuit and quarters 1 , 2 , and 4 ) and RA time ( precircuit and quarters 1 , 2 and 4 ) . A " likely benefit " and moderate ES was found for MT ( quarters 1 and 3 ) , but the effect of caffeine on DT was largely " unclear , " with small ES and only a " likely " chance of benefit ( quarters 2 and 3 ) . Improved decision-making accuracy ( 3.8 % ) after caffeine ingestion was supported by a " likely benefit " ( quarter 1 ) and large ES ( quarters 1 and 4 ) . CONCLUSION Caffeine ingestion may be beneficial to RA performance when athletes are fresh and fatigued Objective : To quantify the acute effect of whole body vibration ( WBV ) training on arm countermovement vertical jump ( ACMVJ ) , grip strength , and flexibility performance . Methods : Eighteen female elite field hockey players each completed three interventions of WBV , control , and cycling in a balanced r and om manner . WBV was performed on a Galileo machine ( 26 Hz ) with six different exercises being performed . For the control , the same six exercises were performed at 0 Hz , whilst cycling was performed at 50 W. Each intervention was 5 min in duration with ACMVJ , grip strength , and flexibility measurements being conducted pre and post intervention . Results : There was a positive interaction effect ( intervention × pre-post ) of enhanced ACMVJ ( p<0.001 ) and flexibility ( p<0.05 ) parameters following WBV ; however no changes were observed after the control and cycling interventions . There was no interaction effect for grip strength following the three interventions . Conclusions : Acute WBV causes neural potentiation of the stretch reflex loop as shown by the improved ACMVJ and flexibility performance . Additionally , muscle groups less proportionally exposed to vibration do not exhibit physiological changes that potentiate muscular performance OBJECTIVES This study investigated the acute effects of a currently implemented team-sport warm-up and two alternative , high-intensity , short- duration protocol s - 5 repetition maximum leg press and small-sided games . DESIGN Ten male soccer players participated in a r and omised , cross-over study . METHODS Participants performed a team-sport , a leg-press , or a small-sided game warm-up . Subsequent performance tests included counter-movement jump , reactive agility , and 15 × 20 m sprints embedded in an intermittent exercise task . Physiological measures included core temperature , blood lactate concentration , heart rate and rating of perceived exertion . Data were analysed using the effect size statistic with 90 % confidence intervals , and percentage change , to determine magnitude of effects . RESULTS Counter-movement jump height improved following the small-sided game ( 6 % , ES : 0.8±0.8 ) and leg-press warm-up ( 2 % , ES : 0.3±0.5 ) , but not after the team-sport warm-up ( ' unclear ' effect ) . Reactive agility improved after the small-sided game ( 4 % , ES : 0.8±0.7 ) and leg-press warm-ups only ( 5 % , ES : 1.1±0.7 ) , when compared to baseline . Mean 20-m sprint times during the intermittent exercise task improved following the leg-press warm-up , when compared with the small-sided game ( 9 % , ES : 0.9±0.3 ) and team-sport warm-ups ( 7 % , ES : 0.6±0.6 ) . Core temperature was lower following the leg-press warm-up compared to small-sided game ( 1 % , ES : 0.9±0.7 ) and the team-sport WUs ( 2 % , ES : 2.4±0.8 ) . Blood lactate was highest following the small-sided game ( 67 % , ES : 2.7±0.8 ) and team-sport warm-ups ( 66 % , ES : 2.9±0.9 ) . CONCLUSIONS A leg-press and small-sided game warm-up may improve acute team-sport performance tests when compared to a traditional warm-up protocol This study examined the effects of caffeine supplementation ( 6 mg·kg-1 ) on performance of a reactive agility test ( RAT ) in 17 elite , male , youth ( M = 14 y ) soccer players . Using a double-blind , repeated- measures design , players completed 4 days of testing on the RAT after a st and ardized warm-up . On day 1 , anthropometric measurements were taken and players were accommo date d to the RAT . On day 2 , baseline performance was established . Caffeine or placebo conditions were r and omly assigned on day 3 and the condition was reversed on day 4 . Players completed 3 r and omized trials of the RAT on days 2 , 3 , and 4 with at least 1 trial to the players ' dominant and nondominant sides . There were no significant differences among conditions in reaction time ( RT ) to the dominant side , heart rates at any point of measurement , or ratings of perceived exertion ( RPE ) after completion of the warm-up . Caffeine produced faster RT to the nondominant side ( P = .041 ) and higher RPE at the conclusion of the RAT ( P = .013 ) . The effect on the total time ( TT ) to complete the agility test to the nondominant side approached significance ( P = .051 ) . Sprint time and TT to either side did not differ . Caffeine supplementation may provide ergogenic benefit to elite , male , youth soccer players UNLABELLED There is little evidence regarding the benefits of caffeine ingestion on cognitive function and skillful actions during sporting performance , especially in sports that are multifaceted in their physiological , skill , and cognitive dem and s. PURPOSE To examine the influence of caffeine on performance during simulated soccer activity . METHODS Twelve male soccer players completed two 90-min soccer-specific intermittent running trials interspersed with tests of soccer skill ( LSPT ) . The trials were separated by 7 days and adhered to a r and omized crossover design . On each occasion participants ingested 6 mg/kg body mass ( BM ) of caffeine ( CAF ) or a placebo ( PLA ) in a double-blind fashion 60 min before exercise .  Movement time , penalties accrued , and total time were recorded for the LSPT . Physiological and performance markers were measured throughout the protocol . Water ( 3 ml/kg BM ) was ingested every 15 min . RESULTS Participants accrued significantly less penalty time in the CAF trial ( 9.7 + /- 6.6 s vs. PLA 11.6 + /- 7.4 s ; p = .02 ) , leading to a significantly lower total time in this trial ( CAF 51.6 + /- 7.7 s vs. PLA 53.9 + /- 8.5 s ; p = .02 ) . This decrease in penalty time was probably attributable to an increased passing accuracy in the CAF trial ( p = .06 ) . Jump height was 2.7 % ( + /- 1.1 % ) higher in the CAF trial ( 57.1 + /- 5.1 cm vs. PLA 55.6 + /- 5.1 cm ; p = .01 ) . CONCLUSIONS Caffeine ingestion before simulated soccer activity improved players '  passing accuracy and jump performance without any detrimental effects on other performance parameters Gabbett , TJ , Sheppard , JM , Pritchard-Peschek , KR , Leveritt , MD , and Aldred , MJ . Influence of closed skill and open skill warm-ups on the performance of speed , change of direction speed , vertical jump , and reactive agility in team sports athletes . J Strength Cond Res 22(5 ) : 1413 - 1415 , 2008-In this study , we evaluated the efficacy of two different dynamic warm-up conditions , one that was inclusive of open skills ( i.e. , reactive movements ) and one that included only preplanned dynamic activities ( i.e. , closed skills ) on the performance of speed , change of direction speed , vertical jump , and reactive agility in team sport athletes . Fourteen ( six male , eight female ) junior ( mean ± SD age , 16.3 ± 0.7 year ) basketball players participated in this study . Testing was conducted on 2 separate days using a within-subjects cross-over study design . Each athlete performed a st and ardized 7-minute warm-up consisting of general dynamic movements and stretching . After the general warm-up , athletes were r and omly allocated into one of two groups that performed a dynamic 15-minute warm-up consisting entirely of open or closed skills . Each of the warm-up conditions consisted of five activities of 3 minute duration . At the completion of the warm-up protocol , players completed assessment s of reactive agility , speed ( 5- , 10- , and 20-m sprints ) , change of direction speed ( T-test ) , and vertical jump . No significant differences ( p > 0.05 ) were detected among warm-up conditions for speed , vertical jump , change of direction speed , and reactive agility performances . The results of this study demonstrate that either open skill or closed skill warm-ups can be used effectively for team sport athletes without compromising performance on open skill and closed skill tasks The purpose of this study was to present a new methodology for the measurement of agility for netball that is considered more ecologically valid than previous agility tests . Specifically , the agility performance of highly-skilled ( n = 12 ) , moderately-skilled ( n = 12 ) and lesser-skilled players ( n = 8) when responding to a life-size , interactive video display of a netball player initiating a pass was compared to a traditional , 
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Reaction time and accuracy , foot placement , and in-line lunge movement have been shown to be related to agility performance .
The contribution of strength remains unclear .
Conclusions Agility tests generally offer good reliability , although this may be compromised in younger participants responding to various scenarios .
A human and /or video stimulus seems the most appropriate method to discriminate between st and ard of playing ability .
Small-sided games and video training may offer effective methods of improving agility , although practical issues may hinder the latter