***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 This study compared the effects of skill-based and plyometric conditioning ( both performed in addition to regular volleyball training twice a week for 12 wk ) on fitness parameters in female junior volleyball players . METHODS The participants [ n = 47 ; age : 16.6 ( 0.6 ) y ; mass : 59.4 ( 8.1 ) kg ; height : 175.1 ( 3.0 ) cm ] were r and omized into a plyometric  ( n = 13 ) , a skill-based ( n = 17 ) , and a  control  ( n = 17 ) groups . The variables included body height , body mass , calf girth , calf skinfold , corrected calf girth , countermovement jump , 20-m-sprint , medicine ball toss , and sit- and -reach test . RESULTS Two-way analysis of variance ( time × group ) effects for time were significant ( P < .05 ) for all variables except body mass . Significant group × time interactions were observed for calf skinfold [ η2 = .14 ; medium effect size ( ES ) ] , 20-m sprint ( η2 = .09 ; small ES ) , countermovement jump ( η2 = .29 ; large ES ) , medicine ball ( η2 = .58 ; large ES ) , with greater gains ( reduction of skinfold ) for plyometric group , and sit- and -reach ( η2 = .35 ; large ES ) , with greater gains in plyometric and skill-based groups . The magnitude-based inference indicated positive changes in 1 ) medicine ball toss and countermovement jump for all groups ; 2 ) sit- and -reach for the plyometric and skill-based groups ; and 3 ) 20-m sprint , calf girth , calf skinfold , and corrected calf girth for plyometric group only . CONCLUSION Selected variables can be improved by adding 2 plyometric training sessions throughout the period of 12 weeks . Additional skill-based conditioning did not contribute to improvement in the studied variables compared with regular volleyball training OBJECTIVE To compare differences in kinematic and kinetic parameters of knee , hip and ankle joints between male and female college volleyball players . DESIGN Cross-sectional study . BACKGROUND L and ing injuries , which usually involve anterior cruciate ligament injuries , are common in volleyball with a higher incidence in females . L and ing preferences of both male and female players may provide additional background about the mechanisms contributing to the anterior cruciate ligament injuries . METHODS Eight female and eight male college volleyball players performed spike and block l and ings from 40 and 60 cm height platforms .  Lower extremity joint kinetics and kinematics , and leg muscle strengths were recorded . RESULTS Females demonstrated significantly lower knee and hip flexion angles compared to their male counterparts in knee flexion at 40 cm spike and hip flexion at 40 cm block l and ings . Group comparison also revealed that male players ' peak knee extensor moment at 60 cm block l and ing was significantly different than female players . Additionally , female players applied significantly higher normalized ground reaction forces and males knee flexion angles and thigh muscle strength results positive and highly correlated but relation could not found in females . It is likely that females may not use their thigh muscles as effective as males in l and ing . CONCLUSION Female volleyball players initiate different lower extremity mechanics during l and ings than that of males . RELEVANCE Identifying the l and ing strategy differences between female and male college volleyball players may provide detailed perspective about the load distribution in lower extremity joints for determining major factors affecting the increased incidence of anterior cruciate ligament injuries in females This study investigated the effects of a plyometric training program and a traditional weight-training program on the onset rate of fatigue in the vertical jump in women . Twenty-five untrained college women ranging in age from 18–35 were r and omly separated into 3 groups : a  plyometric group , a traditional weight-training group , and a control ( untrained ) group . For the purpose of this study , the traditional weight-training group was defined as performing 3 sets of 10 repetitions at 70 % of the subject 's 1 repetition maximum ( 1RM ) . Training took place over a 10-week period for both the plyometric and traditional weight-trained groups . The plyometric group prolonged the onset of fatigue by 3.85 seconds as compared with their pretest data . The traditional weight-training group fatigued 0.55 seconds faster after training was implemented as compared with their pretest data . These results showed a significant difference between the groups in their onset rates of fatigue ( p < 0.05 ) . The results of this study show that a plyometric training program prolongs the onset rate of fatigue in the vertical jump in women as compared with a traditional weight-training program 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 PURPOSE Numerous studies have reported that l and -based plyometrics can improve muscular strength , joint stability , and vertical jump ( VJ ) in athletes ; however , due to the intense nature of plyometric training , the potential for acute muscle soreness or even musculoskeletal injury exists . Performance of aquatic plyometric training ( APT ) could lead to similar benefits , but with reduced risks due to the buoyancy of water . Unfortunately , there is little information regarding the efficacy of APT . Thus , the purpose of this study was to examine the effects of APT on VJ and muscular strength in volleyball players . METHODS Nineteen female volleyball players ( aged 15 + /- 1 yr ) were r and omly assigned to perform 6 wk of APT or flexibility exercises ( CON ) twice weekly , both in addition to traditional preseason volleyball training . Testing of leg strength was performed at baseline and after 6 wk , and VJ was measured at baseline and after 2 , 4 , and 6 wk . RESULTS Similar increases in VJ were observed in both groups after 4 wk ( APT = 3.1 % , CON = 4.9 % ; both P < 0.05 ) ; however , the APT group improved by an additional 8 % ( P < 0.05 ) from week 4 to week 6 , whereas there was no further improvement in the CON group ( -0.9 % ; P = NS ) . After 6 wk , both groups displayed significant improvements in concentric peak torque during knee extension and flexion at 60 and 180 degrees x s(-1 ) ( all P < 0.05 ) . CONCLUSIONS The combination of APT and volleyball training result ed in larger improvements in VJ than in the CON group . Thus , given the likely reduction in muscle soreness with APT versus l and -based plyometrics , APT appears to be a promising training option CONTEXT Plyometric training is credited with providing benefits in performance and dynamic restraint . However , limited prospect i ve data exist quantifying kinematic adaptations such as amortization time , glenohumeral rotation , and scapulothoracic position , which may underlie the efficacy of plyometric training for upper-extremity rehabilitation or performance enhancement . OBJECTIVE To measure upper-extremity kinematics and plyometric phase times before and after an 8-wk upper-extremity strength- and plyometric-training program . DESIGN R and omized pretest-posttest design . SETTING Research laboratory . PARTICIPANTS 40 recreationally active men ( plyometric group , age 20.43 ± 1.40 y , height 180.00 ± 8.80 cm , weight 73.07 ± 7.21 kg ; strength group , age 21.95 ± 3.40 y , height 173.98 ± 11.91 cm , weight 74.79 ± 13.55 kg ) . INTERVENTION Participants were r and omly assigned to either a strength-training group or a strength- and plyometric-training group . Each participant performed the assigned training for 8 wk . MAIN OUTCOME MEASURES Dynamic and static glenohumeral and scapular-rotation measurements were taken before and after the training programs . Dynamic measurement of scapular rotation and time spent in each plyometric phase ( concentric , eccentric , and amortization ) during a ball-toss exercise were recorded while the subjects were fitted with an electromagnetic tracking system . Static measures included scapular upward rotation at 3 different glenohumeral-abduction angles , glenohumeral internal rotation , and glenohumeral external rotation . RESULTS Posttesting showed that both groups significantly decreased the time spent in the amortization , concentric , and eccentric phases of a ball-toss exercise ( P < .01 ) . Both groups also exhibited significantly decreased static external rotation and increased dynamic scapular upward rotation after the training period ( P < .01 ) . The only difference between the training protocol s was that the plyometric-training group exhibited an increase in internal rotation that was not present in the strength-training group ( P < .01 ) . CONCLUSION These findings support the use of both upper-extremity plyometrics and strength training for reducing commonly identified upper-extremity-injury risk factors and improving upper-extremity performance 
    Output:
    
The included studies indicated that plyometric training seems to increase vertical jump performance , strength , horizontal jump performance , flexibility and agility/speed in volleyball players .