Muscle fibre type, size and satellite cell pool in male volleyball players

Introduction. Longitudinal volleyball training stimuli can cause an increase in muscle strength that is brought about by neurological and morphological adaptations, such as changes in muscle fibre composition percentage and cross-sectional area (CSA). Aim of Study. The aim of this study was to examine the biological adaptations of volleyball-players in terms of muscle fiber type composition, cross-sectional area, myonuclei and satellite cell pool in comparison to physically active controls. Material and Methods. Ten professional volleyball-players (VG) and five physically active-persons (CG) participated in this study. Muscle biopsies were obtained from the vastus-lateralis of the dominant leg. Results. Immunohistochemical analysis revealed that although MHC I and MHC IIC muscle fibre distribution was not different between the groups, MHC IIX and MHC IIAX were totally absent in VG and appeared only in the CG. The cross-sectional area revealed a slightly different pattern as both MHC I and IIA were larger for the volleyball players. In accordance, MHC II myonuclei number was moderately larger in the volleyball players, while the satellite cells and their ratio to number of fibres had a large and very large difference, respectively. Conclusions. In conclusion, our study reveals that volleyball training-induced hypertrophy for both type I and II muscle fibres in the vastus lateralis of volleyball players and resulted in a specific shift in muscle fibres containing MHC II isoforms. This hypertrophy of the muscle fibres is associated with an increase in the myonuclear number and satellite cells

Active and non-active time during elite men and women sitting volleyball matches

This paper aims to determine and sort the rally and break-time duration (including the rest time) in elite men’s and women’s Sitting Volleyball matches. The sample of study comprises 9195 rallies were retrieved from 68 (34 men and 34 women) Sitting Volleyball matches (corresponding to 224 sets) of the 2019 European Sitting Volleyball championship which monitored and recorded. Inter-rater and intra-rater reliability coefficients were estimated using Cohen’s kappa coefficient. The results of the study showed that the total average attempts in the block of serve, setting, attack, block and defence are higher in men compared to women (p≤.001). Also, the duration of the rally was longer in men, 5.98s, compared to 4.98s of women (p≤.001). The non-parametric Kruskal-Wallis test demonstrated that in both genders the highest average rally length was recorded in the 5th set (7.42s for men and 5.4s for women, respectively) and in the 3rd period of that set for men (6.22s) and the 1st period for women (5.06s). For both genders, the highest average break-times were recorded in the 5th set (28.23s for men and 27.73s for women) and, in particular, the 3rd period of that set (23.75s for men and 25.14s for women). According to the study result, one of the reasons contributing to the higher rally length in men’s matches is the higher number of attempts for all Sitting Volleyball skills that men performed comparing to women. The results of this study can be used by players, coaching staff, teams and federations for the organization, design, planning and managing of workouts and matches. © 2021, Editura Universitatii din Pitesti. All rights reserved

Spatiotemporal analysis of setting per game complex and origin of the ball in junior female volleyball players

In volleyball, the performance in the passing affects the setter’s strategy and the effectiveness of the attack after the reception or defense. This study aims to assess the spatial and temporal characteristics of the setting choices made by junior female volleyball setters and their performance concerning the origin of the ball and the game complex. The sample for this analysis consists of 3728 setting actions (Complex I = 1.616, Complex II = 1.212). A three-member group of experienced coaches assessed the setting zones’ choices as well as the setting tempo and the performance of junior female setters from 20 volleyball games of teams competing in the final phase of the Greek Junior Championship. The variables under consideration were complex of the game (C1 & CII), origin of the ball (left/middle/right lane for the vertical and front/centre/back lane for the horizontal axis of the court), setting zone (six zones of the court), setting tempo (1st, 2nd & 3rd tempo) and setting performance in a five-level ordinal scale. Inter-rater and intra-rater reliability coefficients were estimated using Cohen’s kappa coefficient with acceptable values. The test of independence for the categorical variables was carried out using the chi-square test. Following the overall independence test, the difference in proportions among all levels of variables was tested. Results showed that junior female setters regardless of the complex and the origin of the ball choose zone 4 in a 3rd tempo, performed in a moderate and good setting. However, the origin of the ball was an important variable for the subsequent setting. The most preferable route of the ball was from a pass in the left lane of the court to an attack in zone 4 regardless of the game complex. Additionally, setters when receiving the ball from the left and middle lane of the court prefer more often zone 3 in 1st tempo, during CI than CII. The results of the study will give useful directions to the coaches of the specific age category regarding the creation of appropriate training programs for the individual improvement of the setters and teams. © JPES

The effect of a proprioception and balance training program on balance and technical skills in youth female volleyball players

A skilled control of postural stability is fundamental in many of the actions performed by volleyball athletes. The effectiveness in serving, forearm passing or setting the ball is affected by the athlete’s ability to control their dynamic balance. When referring to team sports, earlier studies have shown that balance and proprioception training have the potential to induce performance enhancement in selected components of physical fitness and some technical skills but only few of them focus on the field of volleyball. Therefore, the purpose of this study is to investigate the effect of a balance and proprioception training program on dynamic balance and volleyball skills of female volleyball players aged 13-15 years. The sample is consisted by 18 participants who were divided into an experimental group (EG, N=10) and a control group (CG, N=8). In addition to volleyball training, the EG followed an 8-week proprioception and balance training program (3 times/week). Dynamic balance test results were obtained, and participants were rated for the movement outcome (performance score: PS) and movement form (Technique score: TS) of their motor tasks in volleyball skills. Two-factor ANOVA with repeated measurements on the second factor was used to examine the effects of groups and measurements and their interactions. The dynamic balance of the EG showed a significant improvement (p = 0.009). There was an increase in PS for serve (p = 0.022) and TS in forearm-passing (p = 0.001) for the EG, but not for the setting skill (p > 0.05). The study reveals that a targeted proprioception and balance training program can improve the dynamic balance of youth female volleyball players and contribute to the improvement of the movement form of the forearm passing and the movement outcome of the serve skill. © JPES

Upper and Lower Body Power Are Strong Predictors for Selection of Male Junior National Volleyball Team Players

Tsoukos, A, Drikos, S, Brown, LE, Sotiropoulos, K, Veligekas, P, and Bogdanis, GC. Upper and lower body power are strong predictors for selection of male junior National volleyball team players. J Strength Cond Res 33(10): 2760-2767, 2019-The purpose of this study was to determine whether a battery of anthropometric and lower and upper body strength and speed and power tests predicted selection of young volleyball players for a Junior National Team by expert coaches. Fifty-two male junior volleyball players (14.8 ± 0.5 years, height: 1.84 ± 0.05 m, body mass: 72.5 ± 7.1 kg) took part in a training camp and underwent a selection procedure by expert coaches' of the junior national team. Anthropometric data and fitness tests results were obtained and players were graded on a scale from 0 to 100 on the basis of their performance in a volleyball tournament. Selected players were superior in the majority of measured variables (p ≤ 0.017) and had higher grading scores compared with nonselected players (85.3 ± 4.1 vs. 70.5 ± 5.6, respectively, p < 0.01). The combination of spike jump and reach (SJR) test and 3-kg medicine ball throw (MB3) velocity explained 63.5% of the variance in expert coaches' grading (p < 0.001). A multivariate discriminant analysis yielded a significant discriminant function (Wilk's lambda = 0.55, χ = 29.324, p < 0.001, η = 0.82). Spike jump and reach and MB3 were the only variables that contributed to the discriminant function (standardized function coefficients: SJR = 0.68, MB3 = 0.67). Cross-validation results showed that selection was correctly predicted in 14 of the 16 selected players (predictive accuracy: 87.5%) and in 32 of the 36 nonselected players (predictive accuracy: 88.9%). The SJR and MB3 fitness tests can predict a large portion of the variance of expert coaches' grading and successfully discriminate elite young male volleyball players for selection vs. nonselection for a junior national team. This result is very important as performance testing during a selection process may be reduced to only 2 measurements

Upper and lower body power are strong predictors for selection of male junior National volleyball team players

The purpose of this study was to determine whether a battery of anthropometric and lower and upper body strength and speed and power tests predicted selection of young volleyball players for a Junior National Team by expert coaches. Fifty-two male junior volleyball players (14.8 6 0.5 years, height: 1.84 6 0.05 m, body mass: 72.5 6 7.1 kg) took part in a training camp and underwent a selection procedure by expert coaches' of the junior national team. Anthropometric data and fitness tests re- sults were obtained and players were graded on a scale from 0 to 100 on the basis of their performance in a volleyball tour- nament. Selected players were superior in the majority of mea- sured variables (p # 0.017) and had higher grading scores compared with nonselected players (85.3 6 4.1 vs. 70.5 6 5.6, respectively, p , 0.01). The combination of spike jump and reach (SJR) test and 3-kg medicine ball throw (MB3) veloc- ity explained 63.5% of the variance in expert coaches' grading (p , 0.001). A multivariate discriminant analysis yielded a signifi- cant discriminant function (Wilk's lambda = 0.55, x2 = 29.324, p , 0.001, h2 = 0.82). Spike jump and reach and MB3 were the only variables that contributed to the discriminant function (stan- dardized function coefficients: SJR = 0.68, MB3 = 0.67). Cross- validation results showed that selection was correctly predicted in 14 of the 16 selected players (predictive accuracy: 87.5%) and in 32 of the 36 nonselected players (predictive accuracy: 88.9%). The SJR and MB3 fitness tests can predict a large portion of the variance of expert coaches' grading and successfully discriminate elite young male volleyball players for selection vs. nonselection for a junior national team. This result is very important as performance testing during a selection process may be reduced to only 2 measurements