***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: PURPOSE The purpose of this study was to determine whether ballistic resistance training would increase the vertical jump ( VJ ) performance of already highly trained jump athletes . METHODS Sixteen male volleyball players from a NCAA Division I team participated in the study . A Vertec was used to measure st and ing vertical jump and reach ( SJR ) and jump and reach from a three-step approach ( AJR ) . Several types of vertical jump tests were also performed on a Plyometric Power System and a forceplate to measure force , velocity , and power production during vertical jumping . The subjects completed the tests and were then r and omly divided into two groups , control and treatment . All subjects completed the usual preseason volleyball on-court training combined with a resistance training program . In addition , the treatment group completed 8 wk of squat jump training while the control group completed squat and leg press exercises at a 6RM load . Both groups were retested at the completion of the training period . RESULTS The treatment group produced a significant increase in both SJR and AJR of 5.9+/-3.1 % and 6.3+/-5.1 % . respectively . These increases were significantly greater than the pre- to postchanges produced by the control group , which were not significant for either jump . Analysis of the data from the various other jump tests suggested increased overall force output during jumping , and in particular increased rate of force development were the main contributors to the increased jump height . CONCLUSIONS These results lend support to the effectiveness of ballistic resistance training for improving vertical jump performance in elite jump athletes 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 Abstract The aim of this study was to examine the effect of a 10-week combined resistance/sprint training programme in the post-activation potentiation of sprint performance before , between and after resistance training sets . Twenty-six junior basketball players were r and omly divided into a control and a combined training group . The combined training group performed a combined training programme consisting of 5 sets at 5–8 RM ( Repetition Maximum ) half-squats with sprints performed between each set . Post-activation potentiation was considered as the increase in sprint velocity in trials executed between and after the resistance sets compared with the sprint trial performed before the resistance sets of the respective first and last training session . For sprint evaluation the running distances 0–10 and 0–30 m were selected . The intervention increased both strength and sprint performance . No post-activation potentiation effect was observed during the first training session in either group . Post-activation potentiation appeared in the combined training group during the last training session of the intervention in both 0–10 and 0–30 m sprint . This study illustrates that post-activation potentiation effect on sprint performance in junior basketball players , who did not previously follow systematic resistance training , emerges after a 10-week resistance/sprint combined training programme PURPOSE There is little literature comparing contrast training programs typically performed by team-sport athletes within a competitive phase . We compared the effects of two contrast training programs on a range of measures in high-level rugby union players during the competition season . METHODS THE programs consisted of a higher volume-load ( strength-power ) or lower volume-load ( speed-power ) resistance training ; each included a tapering of loading ( higher force early in the week , higher velocity later in the week ) and was performed twice a week for 4 wk . Eighteen players were assessed for peak power during a  bodyweight countermovement jump  ( BWCMJ ) ,  bodyweight squat jump  ( BWSJ ) ,  50 kg countermovement jump  ( 50CMJ ) , 50 kg squat jump ( 50SJ ) , broad jump ( BJ ) , and reactive strength index ( RSI ; jump height divided by contact time during a depth jump ) . Players were then r and omized to either training group and were reassessed following the intervention . Inferences were based on uncertainty in outcomes relative to thresholds for st and ardized changes . RESULTS There were small between-group differences in favor of strength-power training for mean changes in the 50CMJ ( 8 % ; 90 % confidence limits , ±8 % ) , 50SJ ( 8 % ; ±10 % ) , and BJ ( 2 % ; ±3 % ) . Differences between groups for BWCMJ , BWSJ , and reactive strength index were unclear . For most measures there were smaller individual differences in changes with strength-power training . CONCLUSION Our findings suggest that high-level rugby union athletes should be exposed to higher volume-load contrast training which includes one heavy lifting session each week for larger and more uniform adaptation to occur in explosive power throughout a competitive phase of the season Crewther , BT , Kilduff , LP , Cook , CJ , Middleton , MK , Bunce , PJ , and Yang , G-Z. The acute potentiating effects of back squats on athlete performance . J Strength Cond Res 25(12 ) : 3319–3325 , 2011—This study examined the acute potentiating effects of back squats on athlete performance with a specific focus on movement specificity and the individual timing of potentiation . Nine subelite male rugby players performed 3 protocol s on separate occasions using a r and omized , crossover , and counterbalanced design . Each protocol consisted of performance testing before a single set of 3 repetition maximum ( 3RM ) back squats , followed by retesting at ∼15 seconds , 4 , 8 , 12 , and 16 minutes . The 3 tests were countermovement jumps ( CMJs ) , sprint performance ( 5 and 10 m ) , and 3-m horizontal sled pushes with a 100-kg load . Relationships between the individual changes in salivary testosterone and cortisol concentrations and performance were also examined . The 3RM squats significantly ( p < 0.001 ) improved CMJ height at 4 ( 3.9 ± 1.9 % ) , 8 ( 3.5 ± 1.5 % ) , and 12 ( 3.0 ± 1.4 % ) minutes compared with baseline values , but no temporal changes in sprinting and sled times were identified . On an individual level , the peak relative changes in CMJ height ( 6.4 ± 2.1 % , p < 0.001 ) were greater than the 3-m sled ( 1.4 ± 0.6 % ) , 5-m ( 2.6 ± 1.0 % ) , and 10-m sprint tests ( 1.8 ± 1.0 % ) . In conclusion , a single set of 3RM squats was found effective in acutely enhancing CMJ height in the study population , especially when the recovery period was individualized for each athlete . The study results also suggest that the potentiating effects of squats may exhibit some degree of movement specificity , being greater for those exercises with similar movement patterns . The current findings have practical implication s for prescribing warm-up exercises , individualizing training programs , and for interpreting postactivation potentiation research Complex training is the simultaneous combination of heavy resistance training and plyometrics . The objective of this study was to test the effects of complex training vs. heavy resistance or plyometric interventions alone on various power-specific performance measures . Forty-five male division II junior college baseball players participated in 3 separate 4-week resistance training interventions . Subjects were r and omly assigned to one of three groups . In a counterbalanced rotation design , each group participated in complex , heavy resistance , and plyometric training interventions . Each individual was tested in  20-yd ( SP20 ) , 40-yd ( SP40 ) , 60-yd ( SP60 ) , vertical jump , st and ing broad jump , and T-agility measures pre– and post–4-week training interventions . There was no statistical significant difference ( p = 0.11 ) between groups across all performance measures . Review of each distinct training intervention revealed greater percent improvements in SP20 ( 0.55 ; −0.49 ; −0.12 ) , SP40 ( 0.26 ; −0.72 ; −1.33 ) , SP60 ( 0.27 ; 0.15 ; −0.27 ) , st and ing broad jump ( 1.80 ; 0.67 ; 1.1 ) , and T-agility ( 2.33 ; 1.23 ; −0.04 ) with complex training interventions than with the heavy resistance or plyometric training interventions , respectively . Plyometric-only training showed greater percent changes in vertical jump ( 1.90 ) than with complex ( 0.97 ) or heavy resistance training ( 0.36 ) . The present results indicate that complex training can provide strength and conditioning professionals equal , if not slightly greater , improvements in muscular power than traditional heavy resistance– and plyometric-only interventions in moderately trained athletes . Complex training can be another valuable method for short-term power and speed improvements in athletes in isolation or in conjunction with other power development methods OBJECTIVES To compare the impact of short term training with resistance plus plyometric training ( RT+P ) or electromyostimulation plus plyometric training ( EMS+P ) on explosive force production in elite volleyball players . DESIGN Sixteen elite volleyball players of the first German division participated in a training study . METHODS The participants were r and omly assigned to either the RT+P training group ( n=8 ) or the EMS+P training group ( n=8 ) . Both groups participated in a 5-week lower extremity exercise program . Pre and post tests included  squat jumps ( SJ ) , countermovement jumps ( CMJ ) , and drop jumps ( DJ ) on a force plate . The three-step reach height ( RH ) was assessed using a custom-made vertec apparatus . Fifteen m straight and lateral sprint ( S15s and S15l ) were assessed using photoelectric cells with interims at 5 m and 10 m. RESULTS RT+P training result ed in significant improvements in SJ ( + 2.3 % ) and RH ( + 0.4 % ) performance . The EMS+P training group showed significant increases in performance of CMJ ( + 3.8 % ) , DJ ( + 6.4 % ) , RH ( + 1.6 % ) , S15l ( -3.8 % ) and after 5 m and 10 m of the S15s ( -2.6 % ; -0.5 % ) . The comparison of training-induced changes between the two intervention groups revealed significant differences for the SJ ( p=0.023 ) in favor of RT+P and for the S15s after 5 m ( p=0.006 ) in favor of EMS+P. CONCLUSIONS The results indicate that RT+P training is effective in promoting jump performances and EMS+P training increases jump , speed and agility performances of elite volleyball players BACKGROUND AND PURPOSE Assessment of the quality of r and omized controlled trials ( RCTs ) is common practice in systematic review s. However , the reliability of data obtained with most quality assessment scales has not been established . This report describes 2 studies design ed to investigate the reliability of data obtained with the Physiotherapy Evidence Data base ( PEDro ) scale developed to rate the quality of RCTs evaluating physical therapist interventions . METHOD In the first study , 11 raters independently rated 25 RCTs r and omly selected from the PEDro data base . In the second study , 2 raters rated 120 RCTs r and omly selected from the PEDro data base , and disagreements were resolved by a third rater ; this generated a set of individual rater and consensus ratings . The process was repeated by independent raters to create a second set of individual and consensus ratings . Reliability of ratings of PEDro scale items was calculated using multirater kappas , and reliability of the total ( summed ) score was calculated using intraclass correlation coefficients ( ICC [ 1,1 ] ) . RESULTS The kappa value for each of the 11 items ranged from.36 to.80 for individual assessors and from.50 to.79 for consensus ratings generated by groups of 2 or 3 raters . The ICC for the total score was.56 ( 95 % confidence interval=.47-.65 ) for ratings by individuals , and the ICC for consensus ratings was.68 ( 95 % confidence interval=.57-.76 ) . DISCUSSION AND CONCLUSION The reliability of ratings of PEDro scale items varied from " fair " to " substantial , " and the reliability of the total PED 
    Output:
    
As compared to more traditional training regimens , alternating and sequenced complex training showed only small effects in measures of strength , power , and speed .
Based on the relevant and currently available literature , missing data ( e. g. , time for rest interval ) and diverse information regarding training volume and intensity do not allow us to establish evidence -based dose-response relations for complex training .
CONCLUSION Complex training represents an effective training regimen for athletes if the goal is to enhance strength , power , and speed .
Finally , it should be clarified whether alternated and /or sequenced conditioning activities implemented in complex training actually elicit acute PAP effects