BACKGROUND: The study aimed to assess the acute effects of overcoming isometric split squats on subsequent single-leg drop jump (DJ) performance and the contralateral effect in volleyball players, considering training status differences. METHODS: Ten male elite (ELI) and ten amateur (AMA) volleyball players took part in two experimental sessions in which they performed conditioning activity (CA) consisted of 3 sets of overcoming isometric 3-second split squats, differing in the limb used: dominant (DL) or non-dominant (ND-L). Single-leg DJ was performed before and at the 4th and 8th minute post-CA for both limbs. The best post-CA attempt in terms of jump height (JH) was analyzed. RESULTS: Results revealed a significant increase in jump height (JH) in the non-dominant limb (ND-L) from 13.7 ± 2.6 cm to 15.5 ± 2.7 cm after CA performed by the ND-L (p = 0.001; Hedge's g = 0.65). Similarly, the reactive strength index (RSI) of the ND-L improved from 0.40 ± 0.06 to 0.45 ± 0.08 (p = 0.008; g = 0.58). Additionally, contact time in the ND-L increased significantly from 342 ± 36 ms to 375 ± 42 ms after CA performed by the dominant limb (p = 0.001; g = 0.66). In the elite (ELI) group, JH significantly increased from 16.4 ± 2.4 cm to 18.3 ± 3.3 cm (p < 0.001; g = 0.79), while RSI in the dominant limb (DL) improved from 0.47 ± 0.06 to 0.53 ± 0.07 (p = 0.011; g = 0.68). CONCLUSIONS: Results suggest that the examined CA effectively induces the post-activation performance enhancement in DJ among elite volleyball players, with a predominantly local impact on the limb executing the CA. TRIAL REGISTRATION: NCT06459050 (Retrospectively registered).

• Klíčová slova
• Explosive strength, Isometric exercise, Neuromuscular performance, Plyometric training, Post-activation potentiation, Unilateral movement,
• Publikační typ
• časopisecké články MeSH

The aim of this cross-sectional study was to examine relationships of external load variables between beach and indoor volleyball amongst individual positions on the team. The movements of eight beach and fourteen indoor female volleyball players were recorded during elite playoff matches; in total, 2,336 three-dimensional trajectories were analyzed. Time-outs and intervals between rallies or sets were excluded from active play time. In both beach and indoor volleyball, 80% of rallies lasted up to 10 s, and players covered 4.5 to 10 m of court during 60% of rally play. Differences in dependent variables of external load were found between independent variables of sports and player positions (p < 0.05). The distance covered in beach volleyball rallies and Player Load™ parameters was significantly higher by up to 23%. The unstable court surface with sand in beach volleyball elevated explosive Player Load™ (accelerations in all three orthogonal planes of motion higher than 3.5 m/s3) in beach volleyball players compared to those of players on stable flooring in indoor. While beach volleyball blocker and defender positions showed no significant difference in parameters between each other, they differed in all parameters when compared to player positions in indoor volleyball. Indoor blocker and libero reached higher loads than setter, outside and opposite positions in various parameters. Factors that influence external load include the larger relative court areas covered by each player in beach volleyball, complexity of players' roles, and game strategy. This data adds to the knowledge of elite match demands in female volleyball. Specified agility-drill distances and times are essential for training optimization and must be supported by scientific observation. Researchers, coaches, and conditioning specialists should find this helpful for achieving a higher degree of training regulation.

• Klíčová slova
• Female athlete, Match performance, Motion analysis, Movement distance, Player load, Sand surface,
• MeSH
• lidé MeSH
• operantní podmiňování MeSH
• průřezové studie MeSH
• volejbal * MeSH
• výbušné látky * MeSH
• zrychlení MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• výbušné látky * MeSH

The aim of this study was to determine how elite volleyball players employed the arm swing (AS) to enhance their jump performance. The study assessed how the AS influenced the duration and magnitude of the vertical ground reaction force (VGRF) during the main phases (preparatory, braking and accelerating) of the countermovement vertical jump (CMVJ), the starting position of the body at the beginning of the accelerating phase and the moment when the AS began contributing to increasing the jump height. Eighteen elite volleyball players performed three CMVJs with and without an AS. Kinetics and kinematics data were collected using two Kistler force plates and the C-motion system. The time and force variables were evaluated based on the VGRF, and the position of the body and the trajectory of the arm movement were determined using kinematic analysis. The AS improved the CMVJ by increasing the jump height by 38% relative to jumping without an AS. The AS significantly shortened the braking phase and prolonged the accelerating phase, however, it did not influence the preparatory phase or the overall jump duration. The AS also significantly increased the average force during the accelerating phase as well as the accelerating impulse. The AS upward began at 76% into the overall jump duration. The AS did not influence the body position at the beginning of the accelerating phase. These findings can be used to improve performance of the CMVJ with the AS and in teaching beginning volleyball players proper jumping technique.

• Klíčová slova
• VGRF, jump height, jump phases, kinematic analysis, kinetic analysis,
• Publikační typ
• časopisecké články MeSH