***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 Shalfawi , SAI , Haugen , T , Jakobsen , TA , Enoksen , E , and Tønnessen , E. The effect of combined resisted agility and repeated sprint training vs. strength training on female elite soccer players . J Strength Cond Res 27(11 ) : 2966–2972 , 2013—The aim of this study was to compare the effects of in-season combined resisted agility and repeated sprint training with strength training on soccer players ' agility , linear single sprint speed , vertical jump , repeated sprint ability ( RSA ) , and aerobic capacity .  Twenty well-trained elite female soccer players of age ± SD 19.4 ± 4.4 years volunteered to participate in this study . The participants were r and omly assigned to either the agility and repeated sprint training group or to the strength training group . All the participants were tested before and after a 10-week specific conditioning program . The pretest and posttest were conducted on 3 separate days with 1 day of low-intensity training in between . Test day 1 consisted of squat jump ( SJ ) , countermovement jump ( CMJ ) , and RSA . Test day 2 consisted of a 40-m maximal linear sprint and an agility test , whereas a Beep test was conducted on test day 3 to assess aerobic capacity . The agility and repeated sprint training implemented in this study did not have a significant effect on agility , although there was a tendency for moderate improvements from 8.23 ± 0.32 to 8.06 ± 0.21 seconds ( d = 0.8 ) . There was a significant ( p < 0.01 ) and moderate-positive effect on Beep-test performance from level 9.6 ± 1.4 to level 10.8 ± 1.0 , and only a trivial small effect on all other physical variables measured in this study . The strength training group had a positive , moderate , and significant ( p < 0.01 ) effect on Beep-test performance from level 9.7 ± 1.3 to level 10.9 ± 1.2 ( d = 1.0 ) and a significant ( p < 0.05 ) but small effect ( d = 0.5 ) on SJ performance ( 25.9 ± 2.7 to 27.5 ± 4.1 cm ) . Furthermore , the strength training implemented in this study had a trivial and negative effect on agility performance ( d = −0.1 ) . No between-group differences were observed . The outcome of this study indicates the importance of a well-planned program of conditioning that does not result in a decreased performance of the players , the great importance of strength and conditioning specialist in implementing the training program , and the importance of choosing the time of the year to implement such conditioning training programs . However , the fact that the present training program did not cause any decline in performance indicates that it is useful in maintaining the soccer players ' physical performance during the competition period ABSTRACT This study aim ed to investigate the effect of air pollution on diurnal variation of performance in anaerobic tests , cardiovascular and hematological parameters , and blood gases on soccer players following the Yo – Yo Intermittent Recovery Test Level-1 ( YYIRT1 ) . In a r and omized order , 11 healthy soccer players ( mean age : 21.8 [ range : 20–24 ] years ; height : 178.00 [ range : 1.64–1.83 ] cm ; body mass index [ BMI ] : 23.57 [ range : 20.45–28.03 ] kg.m−2 ) performed a YYIRT1 at two different times of day ( TOD ) ( 08:00 h and 18:00 h ) in two areas ( i.e. polluted ( PA ) and non-polluted ( NPA ) ) with a recovery period of ≥ 72 h in between , to determine the maximal oxygen uptake ( VO2max ) . In each test session : resting oral temperature is measured , anaerobic performances ( pre- and post-YYIRT1 ) were performed , cardiovascular parameters and blood sample s were collected at : rest , 3 min and 60 min after the YYIRT1 , to assess blood gases and hematological parameters . Our results showed that , agility performance , VO2max , red blood cells ( RBC ) , hemoglobin ( Hb ) , pH , and bicarbonate levels ( HCO3− ) decrease significantly ( p < 0.001 ) following the YYIRT1 in PA compared to NPA . Likewise , the heart rate ( HR ) , systolic blood pressure ( SBP ) , platelets ( PLT ) , white blood cells ( WBC ) , neutrophiles ( NEUT ) , lymphocytes ( LYM ) , and partial pressure of CO2 levels ( PvCO2 ) were significantly higher ( p < 0.001 ) in PA . This effect was slightly accentuated at 18:00 h for some parameters ( i.e. Agility , HCO3− , HR , PvCO2 , RBC , SBP ) . However , performances of sprint and Sargent jump test ( SJT ) , oral temperature , rate of perceived exertion scales ( RPE ) , partial pressure of O2 ( PvO2 ) , diastolic blood pressure ( DBP ) , and monocytes ( MON ) were not affected by pollution ( p > 0.05 ) . In conclusion , pollution seems to be critical for health stability and performance in response to YYIRT1 especially in the evening and the winter season . Therefore , coaches and athletes should draw attention to the potential importance of l and use planning in their training sessions and competitions in the morning in polluted area to minimize the risk of pollution exposure The purpose of this study was to compare the effects of combined strength and plyometric training with strength training alone on power-related measurements in professional soccer players . Subjects in the intervention team were r and omly divided into 2 groups . Group ST ( n = 6 ) performed heavy strength training twice a week for 7 weeks in addition to 6 to 8 soccer sessions a week . Group ST+P ( n = 8) performed a plyometric training program in addition to the same training as the ST group . The control group ( n = 7 ) performed 6 to 8 soccer sessions a week . Pretests and posttests were 1 repetition maximum ( 1RM ) half squat , countermovement jump ( CMJ ) , squat jump ( SJ ) , 4-bounce test ( 4BT ) , peak power in half squat with 20 kg , 35 kg , and 50 kg ( PP20 , PP35 , and PP50 , respectively ) , sprint acceleration , peak sprint velocity , and total time on 40-m sprint . There were no significant differences between the ST+P group and ST group . Thus , the groups were pooled into 1 intervention group . The intervention group significantly improved in all measurements except CMJ , while the control group showed significant improvements only in PP20 . There was a significant difference in relative improvement between the intervention group and control group in 1RM half squat , 4BT , and SJ . However , a significant difference between groups was not observed in PP20 , PP35 , sprint acceleration , peak sprinting velocity , and total time on 40-m sprint . The results suggest that there are no significant performance-enhancing effects of combining strength and plyometric training in professional soccer players concurrently performing 6 to 8 soccer sessions a week compared to strength training alone . However , heavy strength training leads to significant gains in strength and power-related measurements in professional soccer players 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 Sayers , AL , Farley , RS , Fuller , DK , Jubenville , CB , and Caputo , JL . The effect of static stretching on phases of sprint performance in elite soccer players . J Strength Cond Res 22(5 ) : 1416 - 1421 , 2008-The purpose of this study was to determine which phase of a 30-m sprint ( acceleration and /or maximal velocity ) was affected by preperformance static stretching . Data were collected from 20 elite female soccer players . On two nonconsecutive days , participants were r and omly assigned to either the stretch or no-stretch condition . On the first day , the athletes in the no-stretch condition completed a st and ard warm-up protocol and then performed three 30-m sprints , with a 2-minute rest between each sprint . The athletes in the stretch condition performed the st and ard warm-up protocol , completed a stretching routine of the hamstrings , quadriceps , and calf muscles , and then immediately performed three 30-m sprints , also with a 2-minute rest between each sprint . On the second day , the groups were reversed , and identical procedures were followed . One-way repeated- measures analyses of variance revealed a statistically significant difference in acceleration ( p < 0.0167 ) , maximal-velocity sprint time ( p < 0.0167 ) , and overall sprint time ( p < 0.0167 ) between the stretch and no-stretch conditions . Static stretching before sprinting result ed in slower times in all three performance variables . These findings provide evidence that static stretching exerts a negative effect on sprint performance and should not be included as part of the preparation routine for physical activity that requires sprinting Thomas , K , French , D , and Hayes , PR . The effect of two plyometric training techniques on muscular power and agility in youth soccer players . J Strength Cond Res 23(1 ) : 332 - 335 , 2009-The aim of this study was to compare the effects of two plyometric training techniques on power and agility in youth soccer players . Twelve males from a semiprofessional football club 's academy ( age = 17.3 ± 0.4 years , stature = 177.9 ± 5.1 cm , mass = 68.7 ± 5.6 kg ) were r and omly assigned to 6 weeks of depth jump ( DJ ) or countermovement jump ( CMJ ) training twice weekly . Participants in the DJ group performed drop jumps with instructions to minimize ground-contact time while maximizing height . Participants in the CMJ group performed jumps from a st and ing start position with instructions to gain maximum jump height . Posttraining , both groups experienced improvements in vertical jump height ( p < 0.05 ) and agility time ( p < 0.05 ) and no change in sprint performance ( p > 0.05 ) . There were no differences between the treatment groups ( p > 0.05 ) . The study concludes that both DJ and CMJ plyometrics are worthwhile training activities for improving power and agility in youth soccer players Spierer , DK , Petersen , RA , and Duffy , K. Response time to stimuli in Division I soccer players . J Strength Cond Res 25(4 ) : 1134 - 1141 , 2011-The purpose of this investigation was to examine the effect of auditory stimuli ( AS ) and visual stimuli ( VS ) on sprint time , sprint speed , and reaction time in National Collegiate Athletic Association Division I male soccer players . Fifteen healthy subjects ( mean age 22.1 ± 1.6 years ) volunteered for the study . This experiment was conducted on a regulation soccer field , using a wireless timing system . Subjects stood on a touch- and -release pad and were instructed a prompt ( AS : “ go ” comm and via a microphone interface , VS : movement of a player located 10 m from the start ) to run 20 m through the finish line timing gates without decelerating . After 3 submaximal sprint trials at 50 % , conditions ( AS and VS ) were r and omized and performed 3 times by each subject . The best sprint time , sprint speed , and reaction time were recorded . Paired t-tests were conducted on dependent variables to determine statistically significant differences . An alpha level was set at p ≤ 0.05 . Sprint 
    Output:
    
Except for agility tests , several tests for all categories with acceptable levels of validity and high levels of reliability for adult soccer players are available .