***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: DiStefano , LJ , Padua , DA , Blackburn , JT , Garrett , WE , Guskiewicz , KM , and Marshall , SW . Integrated injury prevention program improves balance and vertical jump height  in children . J Strength Cond Res 24(2 ) : 332 - 342 , 2010-Implementing an injury prevention program to athletes under age 12 years may reduce injury rates . There is limited knowledge regarding whether these young athletes will be able to modify balance and performance measures after completing a traditional program that has been effective with older athletes or whether they require a specialized program for their age . The purpose of this study was to compare the effects of a pediatric program , which was design ed specifically for young athletes , and a traditional program with no program in the ability to change balance and performance measures in youth athletes . We used a cluster-r and omized controlled trial to evaluate the effects of the programs before and after a 9-week intervention period . Sixty-five youth soccer athletes ( males : n = 37 mass = 34.16 ± 5.36 kg , height = 143.07 ± 6.27 cm , age = 10 ± 1 yr ; females : n = 28 mass = 33.82 ± 5.37 kg , height = 141.02 ± 6.59 cm ) volunteered to participate and attended 2 testing sessions in a research laboratory . Teams were cluster-r and omized to either a pediatric or traditional injury prevention program or a control group . Change scores for anterior-posterior and medial-lateral time-to-stabilization measures and maximum vertical jump height and power were calculated from pretest and post-test sessions . Contrary with our original hypotheses , the traditional program result ed in positive changes , whereas the pediatric program did not result in any improvements . Anterior-posterior time-to-stabilization decreased after the traditional program ( mean change ± SD = −0.92 ± 0.49 s ) compared with the control group ( −0.49 ± 0.59 s ) ( p = 0.003 ) . The traditional program also increased vertical jump height ( 1.70 ± 2.80 cm ) compared with the control group ( 0.20 ± 0.20 cm ) ( p = 0.04 ) . There were no significant differences between control and pediatric programs . Youth athletes can improve balance ability and vertical jump height after completing an injury prevention program . Training specificity appears to affect improvements and should be considered with future program design Abstract Complex training , a combination of resistance training and plyometrics is growing in popularity , despite limited support for its efficacy . In pre- and early pubertal children , the study of complex training has been limited , and to our knowledge an examination of its effect on anaerobic performance characteristics of the upper and lower body has not been undertaken . Furthermore , the effect of detraining after complex training requires clarification . The physical characteristics ( mean±s ) of the 54 male participants in the present study were as follows : age 12.3 ± 0.3 years , height 1.57 ± 0.07 m , body mass 50.3 ± 11.0 kg . Participants were r and omly assigned to an experimental ( n = 33 ) or control group ( n = 21 ) . The training , which was performed three times a week for 12 weeks , included a combination of dynamic constant external resistance and plyometrics . After training , participants completed 12 weeks of detraining . At baseline , after training and after detraining , peak and mean anaerobic power , dynamic strength and athletic performance were assessed . Twenty-six participants completed the training and none reported any training-related injury . Complex training was associated with small increases ( ≤5.5 % ) in peak and mean power during training , followed by decreases of a similar magnitude ( ≤ −5.9 % ) during detraining ( P < 0.05 ) . No changes or minor , progressive increases ( ≤1.5 % ) were evident in the control group ( P > 0.05 ) . In the experimental group , dynamic strength was increased by 24.3 – 71.4 % ( dependent on muscle group ; P < 0.01 ) , whereas growth-related changes in the control group varied from 0 to 4.4 % ( P > 0.05 ) . For 40-m sprint running , basketball chest pass and vertical jump test performance , the experimental group saw a small improvement ( ≤4.0 % ) after training followed by a decline ( ≤ −4.4 % ) towards baseline during detraining ( P < 0.05 ) , whereas the control group experienced no change ( P > 0.05 ) . In conclusion , in pre- and early pubertal boys , upper and lower body complex training is a time-effective and safe training modality that confers small improvements in anaerobic power and jumping , throwing and sprinting performance , and marked improvements in dynamic strength . However , after detraining , the benefits of complex training are lost at similar rates to other training modalities Meylan , C and Malatesta D. Effects of in-season plyometric training within soccer practice on explosive actions of young players . J Strength Cond Res 23(9 ) : 2605 - 2613 , 2009-In soccer , explosive actions such as jumping , sprinting , and changes of direction are essential to optimal performance not only in adults , but also in children 's games . The purpose of the present investigation was to determine the influence of a short-term plyometric training within regular soccer practice on explosive actions of early pubertal soccer players during the in-season . Fourteen children ( 13.3 ± 0.6 years ) were selected as the training group ( TG ) and 11 children ( 13.1 ± 0.6 years ) were defined as the control group ( CG ) . All children were playing in the same league and trained twice per week for 90 minutes with the same soccer drills . The TG followed an 8-week plyometric program ( i.e. , jumping , hurdling , bouncing , skipping , and footwork ) implemented as a substitute for some soccer drills to obtain the same session duration as CG . At baseline and after training , explosive actions were assessed with the following 6 tests : 10-meter sprint , agility test , 3 vertical jump tests ( squat jump [ SJ ] , countermovement jump [ CMJ ] , contact test [ CT ] and multiple 5 bounds test [ MB5 ] ) . Plyometric training was associated with significant decreases in 10-m sprint time ( −2.1 % ) and agility test time ( −9.6 % ) and significant increases in jump height for the CMJ ( + 7.9 % ) and CT ( + 10.9 % ) . No significant changes in explosive actions after the 8-week period were recorded for the CG . The current study demonstrated that a plyometric program within regular soccer practice improved explosive actions of young players compared to conventional soccer training only . Therefore , the short-term plyometric program had a beneficial impact on explosive actions , such as sprinting , change of direction , and jumping , which are important determinants of match-winning actions in soccer performance BACKGROUND Demographic and psychosocial correlates of activity in domains other than recreational activity have not been well characterized and may be particularly relevant for health promotion efforts aim ed at women . METHODS Cross-sectional relationships between recreational , occupational , and household/caregiving physical activity and demographic and psychosocial factors were assessed with a mail survey in a r and om sample of 2,636 ethnically diverse women members of a large health maintenance organization , ages 20 - 65 . Activity was assessed with a modified Baecke question naire that uses categorical responses regarding frequency of domain-specific activities to create four semicontinuous activity indices ( sports/exercise , active living , occupational , household/caregiving ) . RESULTS Multivariable logistic regression analysis showed that the likelihood of being in the highest quartile of the sports/exercise and active-living indices , compared with the other three quartiles , was decreased among older , nonwhite , less well educated , heavier women who had young children at home , lacked motivation to exercise , and perceived external obstacles to exercise behavior . The odds ratios ( ORs ) ranged from 0.38 , 95 % confidence interval ( CI ) 0.33 - 0.45 , associated with low motivation , to 0.95 , 95 % CI 0.93 - 0.98 , associated with increasing body mass index . Social support and confidence in one 's ability to continue to exercise , even when faced with other pressures and dem and s ( termed self-efficacy ) , were associated with increased likelihood of high levels of sports/exercise and active living ( OR = 2.34 , 95 % CI 1 . 83 - 2.98 and OR = 3.96 , 95 % CI 2.92 - 5.38 , respectively ) . In contrast , the highest quartile of household/caregiving activity was positively associated with increasing age ( OR = 1.28 , 95 % CI 1.16 - 1.42 ) , Hispanic ethnicity ( OR = 1.58 , 95 % CI 0.55 - 1.01 ) , being married ( OR = 1.70 , 95 % CI 1.33 - 2.18 ) ,  having young children at home ( OR = 6.99 , 95 % CI 4.33 - 11 ) , and greater time constraints as a barrier to exercise ( OR = 1.55 , 95 % CI 1.38 - 1.74 ) and was negatively associated with employment ( OR = 0.38 , 95 % CI 0.30 - 0.47 ) . Increased likelihood of the highest quartile of occupational activity was associated with high school education or less ( OR = 2.26 , 95 % CI 1.74 - 2.94 ) and current smoking ( OR = 1.66 , 95 % CI 1.23 - 2.23 ) , while self-efficacy regarding exercise was associated with decreased likelihood ( OR = 0 . 77 , 95 % CI 0.61 - 0.96 ) . CONCLUSIONS These findings suggest that demographic and psychosocial correlates of physical activity vary by domain and that initiatives to promote physical activity in the population need to take these differences into account The purpose of this study was to investigate the effect of plyometric training on running velocity ( RV ) and squat jump ( SJ ) in prepubescent boys . Fifteen boys ( 11.1 ± 0.5 years ) followed a 10-week plyometric program ( JUMP group ) . Another group of 15 boys ( 10.9 ± 0.7 years ) followed only the physical education program in primary school and was used as the control group ( CONT group ) . Running distances ( 0–10 m , 10–20 m , 20–30 m , and 0–30 m ) , were selected as testing variables to evaluate the training program . The total number of jumps was initially 60 per session , which was gradually increased over a period of 10 weeks to 100 per session . Results revealed significant differences between CONT and JUMP groups in RV and SJ . In JUMP group the velocity for the running distances 0–30 , 10–20 , and 20–30 m increased ( p < 0.05 ) , but not for the distance 0–10 m ( p > 0.05 ) . Additionally , the SJ performance of the JUMP group increased significantly , as well ( p < 0.05 ) . There was no change in either RV or SJ for the CONT group . These results indicate that plyometric exercises can improve SJ and RV in prepubertal boys . More specifically , this program selectively influenced the maximum velocity phase , but not the acceleration phase The purpose of this study was to investigate the motor unit activation of the quadriceps ( Q ) , hamstring ( H ) , and gastrocnemius ( G ) muscle groups during a variety of plyometric exercises to further underst and the nature of these exercises . Twenty-three athletes volunteered to perform r and omly ordered plyometric exercises  , thought to cover a continuum of intensity levels , including two-foot ankle hops ; 15-cm cone hops ; tuck , pike , and box jumps ; one- and two-leg vertical jump and reach ; squat jumps with approximately 30 % of their 1RM squat load ; and 30- and 61-cm depth jumps . Integrated electromyographic data were analyzed for each exercise using a one-way repeated- measures ANOVA . Results revealed significant main effects for the Q when all subjects are analyzed , as well as for separate analysis of men , women , subjects with vertical jumps greater than 50 cm , and those with vertical jumps less than or equal to 50 cm ( p ≤ 0.05 ) . Significant main effects were also found for the G muscle group in the analysis of all subjects , as well as for men and subjects with vertical jumps greater than 50 cm ( p ≤ 0.05 ) . No significant main effects were found for the H muscle group . Pairwise comparisons revealed a variety of differences among plyometric exercises . In some cases , plyometrics previously reported to be of high intensity , such as the depth jump , yielded relatively little motor unit recruitment compared with exercises typically thought to be of low intensity . Results can assist the practitioner in creating plyometric programs based on the nature of the motor unit recruitment 
    Output:
    
Plyometric training had a large effect on improving the ability to run and jump .
Preliminary evidence suggests plyometric training also had a large effect on increasing kicking distance , balance , and agility .
The current evidence suggests that a twice a week program for 8 - 10 weeks beginning at 50 - 60 jumps a session and increasing exercise load weekly results in the largest changes in running and jumping performance .
An alternative program for children who do not have the capability or tolerance for a twice a week program would be a low-intensity program for a longer duration .