***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 a 12 week conditioning programme involving speed , agility and quickness ( SAQ ) training and its effect on agility performance in young soccer players . Soccer players were r and omly assigned to two groups : experimental group ( EG ; n = 66 , body mass : 71.3 ± 5.9 kg ; body height : 1.77 ± 0.07 m ) and control group ( CG ; n = 66 , body mass : 70.6 ± 4.9 kg ; body height : 1.76 ± 0.06 m ) . Agility performance was assessed using field tests : Slalom ; Slalom with ball ; Sprint with 90 ° turns ; Sprint with 90 ° turns with ball ; Sprint with 180 ° turns ; Sprint with backward and forward running ; Sprint 4 x 5 m. Statistically significant improvements ( p < 0.05 ) between pre and post training were evident for almost all measures of agility , with and without the ball , with the exception being the Sprint with backward and forward running . This suggests that SAQ training is an effective way of improving agility , with and without the ball , for young soccer players and can be included in physical conditioning programmes . Key pointsSAQ training appears to be an effective way of improving agility with and without the ball in young soccer playersSoccer coaches could use this training during pre-season and in-season trainingCompared with pre-training , there was a statistically significant improvement in all but one measure of agility , both with and without the ball after SAQ training Abstract In a r and omised controlled trial design , effects of 6 weeks of plyometric training on maximal-intensity exercise and endurance performance were compared in male and female soccer players . Young ( age 21.1 ± 2.7 years ) players with similar training load and competitive background were assigned to training ( women , n = 19 ; men , n = 21 ) and control ( women , n = 19 ; men , n = 21 ) groups . Players were evaluated for lower- and upper-body maximal-intensity exercise , 30 m sprint , change of direction speed and endurance performance before and after 6 weeks of training . After intervention , the control groups did not change , whereas both training groups improved jumps ( effect size ( ES ) = 0.35–1.76 ) , throwing ( ES = 0.62–0.78 ) , sprint ( ES = 0.86–1.44 ) , change of direction speed ( ES = 0.46–0.85 ) and endurance performance ( ES = 0.42–0.62 ) . There were no differences in performance improvements between the plyometric training groups . Both plyometric groups improved more in all performance tests than the controls . The results suggest that adaptations to plyometric training do not differ between men and women The purpose of this study was to examine the effects of unilateral isometric leg extension strength training on the strength and integrated electromyogram ( IEMG ) of both the trained and untrained limbs at multiple joint angles . A training ( TRN ) group [ nine women ; mean ( SD ) age , 20(1 ) years ]  exercised for 6 weeks with isometric leg extensions at 80 % of maximal isometric torque . A control ( CTL ) group [ eight women ; 21(1 ) years ]  did not exercise . The training was performed three times per week on a Cybex II isokinetic dynamometer at a joint angle where the lever arm was 0.79 rad below the horizontal plane . The subjects were tested pre- and posttraining for maximal unilateral isometric torque in both limbs at joint angles of zero , 0.26 , 0.79,1.31 , and 1.57 rad below the horizontal plane . Bipolar surface electrodes were used to record the IEMG of the vastus lateralis ( VL ) and vastus medialis ( VM ) during the isometric tests . Three univariate ( torque , IEMG-VL , and IEMG-VM ) four-way ( group x time x limb x angle ) mixed factorial ANOVAs were used to analyze the data . The results indicated joint angle specificity for isometric torque in the TRN group only , with significant increases in torque at 0.79 ( P = 0.0004 ) and 1.31 ( P = 0.0039 ) rad . No significant increases in torque were found in the untrained limb of the TRN group or in either limb of the CTL group . Similarly , there were no significant changes in IEMG as a result of the training for the VL or VM . The joint-angle-specific strength increases without concomitant increases in IEMG were hypothesized to result from joint-angle-specific decreases in antagonistic co-contraction and /or preferential hypertropy of the quadriceps femoris at specific levels of the muscle group Abstract Ramírez-Campillo , R , Gallardo , F , Henriquez-Olguín , C , Meylan , CMP , Martínez , C , Álvarez , C , Caniuqueo , A , Cadore , EL , and Izquierdo , M. Effect of vertical , horizontal , and combined plyometric training on explosive , balance , and endurance performance of young soccer players . J Strength Cond Res 29(7 ) : 1784–1795 , 2015—The aim of this study was to compare the effects of 6 weeks of vertical , horizontal , or combined vertical and horizontal plyometric training on muscle explosive , endurance , and balance performance .  Forty young soccer players aged between 10 and 14 years were r and omly divided into control ( CG ; n = 10 ) , vertical plyometric group ( VG ; n = 10 ) , horizontal plyometric group ( HG ; n = 10 ) , and combined vertical and horizontal plyometric group ( VHG ; n = 10 ) . Players performance in the vertical and horizontal countermovement jump with arms , 5 multiple bounds test ( MB5 ) , 20-cm drop jump reactive strength index ( RSI20 ) , maximal kicking velocity ( MKV ) , sprint , change of direction speed ( CODS ) , Yo-Yo intermittent recovery level 1 test ( Yo-Yo IR1 ) , and balance was measured . No significant or meaningful changes in the CG , apart from small change in the Yo-Yo IR1 , were observed while all training programs result ed in meaningful changes in explosive , endurance , and balance performance . However , only VHG showed a statistically significant ( p ⩽ 0.05 ) increase in all performance test and most meaningful training effect difference with the CG across tests . Although no significant differences in performance changes were observed between experimental groups , the VHG program was more effective compared with VG ( i.e. , jumps , MKV , sprint , CODS , and balance performance ) and HG ( i.e. , sprint , CODS , and balance performance ) to small effect . The study demonstrated that vertical , horizontal , and combined vertical and horizontal jumps induced meaningful improvement in explosive actions , balance , and intermittent endurance capacity . However , combining vertical and horizontal drills seems more advantageous to induce greater performance improvements Abstract The aim of this study was to analyse the effects of a combined strength-training programme ( full-back squat , YoYoTM leg curl , plyometrics and sled towing exercises ) on performance in elite young soccer players and to examine the effects when this training programme was performed one or two days per week . Thirty-six male soccer players ( U-17 to U-19 ) were recruited and assigned to experimental groups ( EXP1 : 1 s w−1 ; EXP2 : 2 s w−1 ) or a control group ( CON ) . Performance was assessed through a countermovement jump ( CMJ ) test ( relative peak power [ CMJPP ] and CMJ height [ CMJH ] ) , a 20-m linear sprint test with split-times at 10-m , and a change of direction test ( V-cut test ) 1 week before starting the training programme and also 1 week after performing such training programme . Within-group analysis showed substantial improvements in CMJ variables ( ES : 0.39–0.81 ) and COD ( ES : 0.70 and 0.76 ) in EXP1 and EXP2 , while EXP2 also showed substantial enhancements in all linear sprinting tests ( ES : 0.43–0.52 ) . Between-group analysis showed substantially greater improvements in CMJ variables ( ES : 0.39–0.68 ) in experimental groups in comparison to CON . Furthermore , EXP2 achieved a substantial better performance in 20-m ( ES : 0.48–0.64 ) than EXP1 and CON . Finally , EXP2 also showed greater enhancements in 10-m ( ES : 0.50 ) and V-cut test ( ES : 0.52 ) than EXP1 . In conclusion , the combined strength-training programme improved jumping ability , independently of training frequency , though the achievement of two sessions per week also enhanced sprinting abilities ( linear and COD ) in young soccer players Power training programs have proved to be effective in improving components of physical fitness such as speed . According to the concept of training specificity , it was postulated that exercises must attempt to closely mimic the dem and s of the respective activity . When transferring this idea to speed development , the purpose of the present study was to examine the effects of resisted sprint ( RST ) vs. traditional power training ( TPT ) on physical fitness in healthy young adults . Thirty-five healthy , physically active adults were r and omly assigned to a RST ( n = 10 , 23 ± 3 years ) , a TPT ( n = 9 , 23 ± 3 years ) , or a passive control group ( n = 16 , 23 ± 2 years ) . RST and TPT exercised for 6 weeks with three training sessions/week each lasting 45–60 min . RST comprised frontal and lateral sprint exercises using an exp and er system with increasing levels of resistance that was attached to a treadmill ( h/p/cosmos ) . TPT included ballistic strength training at 40 % of the one-repetition-maximum for the lower limbs ( e.g. , leg press , knee extensions ) . Before and after training , sprint ( 20-m sprint ) , change-of-direction speed ( T-agility test ) , jump ( drop , countermovement jump ) , and balance performances ( Y balance test ) were assessed . ANCOVA statistics revealed large main effects of group for 20-m sprint velocity and ground contact time ( 0.81 ≤ d ≤ 1.00 ) . Post-hoc tests showed higher sprint velocity  following RST and TPT ( 0.69 ≤ d ≤ 0.82 ) when compared to the control group , but no difference between RST and TPT . Pre-to-post changes amounted to 4.5 % for RST [ 90%CI : ( −1.1%;10.1 % ) , d = 1.23 ] and 2.6 % for TPT [ 90%CI : ( 0.4%;4.8 % ) , d = 1.59 ] . Additionally , ground contact times during sprinting were shorter following RST and TPT ( 0.68 ≤ d ≤ 1.09 ) compared to the control group , but no difference between RST and TPT  . Pre-to-post changes amounted to −6.3 % for RST [ 90%CI : ( −11.4%;−1.1 % ) , d = 1.45 ) and −2.7 % for TPT [ 90%CI : ( −4.2%;−1.2 % ) , d = 2.36 ] . Finally , effects for change-of-direction speed , jump , and balance performance varied from small-to-large . The present findings indicate that 6 weeks of RST and TPT produced similar effects on 20-m sprint performance compared with a passive control in healthy and physically active , young adults . However , no training-related effects were found for change-of-direction speed , jump and balance performance . We conclude that both training regimes can be applied for speed development The purpose of this study was to examine the effect of 8 weeks combined balance and plyometric training on the physical fitness of female adolescent basketball players . Twenty six healthy regional-level players were r and omly assigned to either an  experimental group ( E ; n = 16 , age = 16.4 ± 0.5 ) or a  control group ( C ; n = 10 , age = 16.5 ± 0.5 ) . C maintained their normal basketball training schedule , whereas for 8 weeks E replaced a part of their st and ard regimen by biweekly combined training sessions . Testing before and after training included the Squat Jump ( SJ ) , Countermovement Jump ( CMJ ) , Drop Jump ( DJ ) , 5 , 10 and 20-m sprints , Stork Balance Test ( SBT ) , Y-Balance Test ( YBT ) and Modified Illinois Change of Direction Test ( MICODT ) . Results indicated no significant inter-group differences in SJ and CMJ height ; however , E increased their DJ height ( p<0.05 , Cohens'd = 0.11 ) . No significant inter-group differences were found for sprint performance or SBT , but dynamic YBT tended to a significant group interaction ( p = 0.087 , d = 0.006 ) . Post hoc analysis also showed a significant increase of MICODT for E ( Δ 6.68 % , p = 0.041 , d = 0.084 ) . In summary , the addition of 8 weeks of balance and plyometric training to regular in-season basketball training proved a safe and feasible intervention that enhanced DJ height , balance , and agility for female adolescent basketball players relative to the st and ard basketball training regimen The aim of this study was to compare changes in young soccer player 's fitness after traditional bilateral vs. unilateral combined plyometric and strength training .  Male athletes were r and omly divided in two groups ; both received the same training , including strength training for knee extensors and flexors , in addition to horizontal plyometric training drills . The only difference between groups was the mode of drills technique :  unilateral ( UG ; n = 9 ; age , 17.3  
    Output:
    
The review revealed no clear consensus on which training form is optimal to develop COD performance .
All training forms result ed in an increase in performance from almost no ES to large ES .
Conclusions The results of the study indicate that COD ability is a specific skill , whereas the COD task , the sports require determines which training form is the most effective to develop COD ability .