No abstract

Volleyball involves movements with and/or without horizontal approaches (i.e., spike jumps, jump setting, blocking). The 5-jump test (5JT) was suggested to assess lower limb explosive power of athletes competing in some disciplines (e.g., soccer, judo, running). It appears that no previous study has investigated the 5JT performance components in volleyball players. This study aimed to test the relationship between 5JT performance and two specific laboratory tests for explosive power (i.e., countermovement jump [CMJ] and squat jump [SJ]). Forty volleyball players (boys, mean age: 12.4 ± 0.8 years) were tested for 5JT, CMJ, and SJ tests. 5JT performance was expressed in absolute terms (m), and relative to leg length (5JTLL) and body mass (5JTBM). The SJ and CMJ tests were evaluated using the optojump photoelectric cells and the following data were collected: peak power (Pp) of jump (W, W.kg-0.67), peak jumping force (Fpeak, N), peak jumping velocity (Vpeak, m/s), peak heights of CMJ and SJ (CMJH and SJH, respectively, cm). Only significant ( p < .05) Pearson product-moment correlations ( r) > 0.30 were considered. 5JT performance was significantly correlated with SJ, Vpeak ( r = 0.90), SJH ( r = 0.88), Pp [W.kg-0.67 ( r = 0.86), W ( r = 0.72)], Fpeak ( r = 0.45); and CMJ, Vpeak ( r = 0.82), CMJH ( r = 0.80), Pp [W.kg-0.67 ( r = 0.89), W ( r = 0.85)], Fpeak ( r = 0.73). 5JTLL values were significantly related to SJ, Pp [W ( r = 0.81), W.kg-0.67 ( r = 0.74)], Vpeak ( r = 0.82); and CMJ, Pp [W ( r = 0.73), W.kg-0.67 ( r = 0.84)], Vpeak ( r = 0.75), Fpeak ( r = 0.67)]. 5JTBM values were significantly related to SJ, Pp (W, r = −0.43). To conclude, in youth volleyball players, the 5JT may be viewed as an explosive strength diagnostic instrument under field circumstances.

No abstract

This study compared the effects of different sprint ball-based training programs on fitness-related performances in youth soccer players. Forty male players (age: 15.2 ± 0.6 yrs) participated in a short-term (8 weeks) randomized parallel fully controlled training study, with pre-to-post measurements. Players were randomly assigned to 3 sprint ball-based training groups: training with combined sprint (performing linear and change of direction sprints; CST), or using linear sprint (LST), or performing sprint with change of direction (CODT) and to a control group (CONT). Pre- and post-training players completed a test battery involving linear sprinting (10 and 20 m, and flying 10 m), 505 test (COD), 15 m test with ball (CODB), countermovement jump test (CMJ test) and maximal oxygen consumption (VO2max). All physical performance’ variables improved after the training intervention (all p < 0.05; ES ≥ 0.2). No main effect of groups was observed in linear sprinting, CMJ and VO2max (p > 0.05; ES < 0.2). A training group main effect was found (p < 0.0001; ES = 0.50) for COD with CODT induced better performance than LST and CONT (all p <0.0001; ES > 0.8). Also, a training group main effect (p = 0.009; ES = 0.35) was found for CODB with CODT elicited better performance than LST and CONT (all p = 0.001; ES > 0.80). Our findings suggest that ball-based training programs were more effective to improve fitness levels in youth players during the in-season period and that CODT modality was more effective to improve COD and CODB performances.

Background: In youth volleyball players, no previous study has investigated the relationships between the components of the force-velocity test (FVt) and those of the horizontal jump approach, speed test, and agility test. We aimed to determine the relationships that exist between lower-body power measured via a laboratory test (ie; FVt) and some field tests [horizontal jump (ie; 5-jump test, speed test (ie; 20-m sprint) and agility test (ie; pro-agility shuttle)] in youth volleyball players. Methods: Thirty-one youth volleyball players were investigated for changing of direction (pro-agility shuttle), 5-jump test, and absolute/relative peak leg power (Ppeak) during the FVt. Speeds (s) during a 20-m sprint were measured at 5, 10, and 20 m (T5, T10 and T20, respectively). 5-jump test performance was expressed in absolute terms (5JTA, m), and relative to leg length (5JTLL) and body mass (5JTBM). Results: This study identified i) “high” correlations between FVtPpeak (W) and 20-m sprint [T5 (r=-0.858), T10 (r=-0.707), and T20 (r=-0.762)], and pro-agility shuttle (r=-0.745), ii) “good” correlations between FVtPpeak (W.kg) and 5JTA(r=0.531), and iii) “fair” correlations between FVtPpeak (W) and 5JTA(r=0.499),between FVtPpeak (W.kg-0.67) and 5JTA (r=0.489), and 20-m sprint [T5(r=-0.370), T10(r=-0.364)]. Conclusions: Tthe pro-agility shuttle, 20-m sprint, and 5JT can be used to evaluate lower limb explosive power in youth volleyball players.

No abstract

Background: Although previous research in pediatric populations has reported performance enhancements following long-term plyometric training, the acute effects of plyometric exercises on measures of balance, vertical jump, reactive strength, and leg stiffness remain unclear. Knowledge on the acute effects of plyometric exercises (i.e., maximal versus submaximal hurdle jumps) help to better plan and program warm-up sessions before training or competition.Objectives: To determine the acute effects of maximal vs. submaximal hurdle jump exercise protocols executed during one training session on balance, vertical jump, reactive strength, and leg stiffness in young volleyball players.Materials and methods: Thirty male youth volleyball players, aged 12–13 years, performed two plyometric exercise protocols in randomized order. In a within-subject design, the protocols were conducted under maximal (MHJ; 3 sets of 6 repetitions of 30-cm hurdle jumps) and submaximal (SHJ; 3 sets of 6 repetitions of 20-cm hurdle jumps) hurdle jump conditions. Pre- and post-exercise, balance was tested in bipedal stance on stable (firm) and unstable surfaces (foam), using two variables [center of pressure surface area (CoP SA) and velocity (CoP V)]. In addition, the reactive strength index (RSI) was assessed during countermovement maximal jumping and leg stiffness during side-to-side submaximal jumping. Testing comprised maximal countermovement jumps (CMJ).Results: Significant time-by-condition interactions were found for CoP SA firm (p &lt; .0001; d = 0.80), CoP SA foam (p &lt; .0001; d = 0.82), CoP V firm (p &lt; .0001; d = 0.85), and CoP V foam (p &lt; .0001; d = 0.83). Post-hoc analyses showed significant improvements for all balance variables from pretest to posttest for MHJ but not SHJ. All power tests displayed significant time-by-group interactions for countermovement jumps (p &lt; .05; d = 0.42), RSI (p &lt; .0001; d = 1.58), and leg stiffness (p &lt; .001; d = 0.78). Post-hoc analyses showed significant pre-post CMJ (p &lt; .001, d = 1.95) and RSI (p &lt; .001, d = 5.12) improvements for MHJ but not SHJ. SHJ showed larger pre-post improvements compared with MHJ for leg stiffness (p &lt; .001; d = 3.09).Conclusion: While the MHJ protocol is more effective to induce acute performance improvements in balance, reactive strength index, and vertical jump performance, SHJ has a greater effect on leg stiffness. Due to the importance of postural control and muscle strength/power for overall competitive performance in volleyball, these results suggest that young volleyball players should implement dynamic plyometric protocols involving maximal and submaximal hurdle jump exercises during warm-up to improve subsequent balance performance and muscle strength/power.

Background It has previously been shown that drop jump height is an effective programming parameter in plyometric jump training. Less is known on the usage of maximal rebound jump height from a distinct drop height as a parameter for individualized plyometric jump training. Aim This study examined the effects of 8-weeks of two drop jump (DJ) training modalities using maximal rebound height (MRHT) vs fixed (FDHT) drop height programming approaches on selected measures of physical fitness in young volleyball players. Methods Thirty male youth volleyball players aged 14 to 16 years were randomly assigned to a MRHT (n = 15) or a FDHT (n = 15) group. The MRHT group performed DJ exercises using a drop height according to the individual’s maximal rebound jump height from 20-cm, 30-cm, 40-cm, and 50-cm drop heights. The FDHT group performed DJs following a standardized drop height (30-cm) across the 8-week intervention period. The overall training volume was similar between MRHT and FDHT with 3 sets of 10 repetitions of DJ exercises per session. Pre- and post-training, DJs were tested from 30, 40, and 50-cm drop heights. In addition, dynamic balance (Y-balance test) as well as linear sprint and change-of-direction (CoD) speed were assessed. Results Significant group-by-time interactions were found for DJ, balance, and linear sprint tests (p < 0.0001; d = 0.12–0.88) but not for CoD speed. Post-hoc tests showed significant improvements in favor of the MRHT group for DJ heights from 30-cm (Δ20.4%, p < 0.0001, d = 6.31), 40-cm DJ (Δ20.3%, p < 0.0001, d = 3.46), 50-cm DJ (Δ18.3%, p < 0.0001, d = 4.99), 5-m (Δ9.2%, p < 0.001, d = 1.21) and 20-m (Δ7.4%, p < 0.01, d = 1.60) linear sprint speed. Conclusions MRHT is a safe and effective training regime to improve DJ and linear sprint speed performance. Due to the importance of vertical jumps and short accelerations for overall competitive performance in volleyball, our results suggest that young male players should perform MRHT as part of plyometric jump training if the goal is to improve acceleration and vertical jump performance.