Knee peak torque (PT) is associated to jump performance in volleyball players. It is not clear whether muscle strength imbalances of the knee joint can influence jump performance. The purpose of study was to analyse the association between PT and knee muscular imbalances with jump performance in professional volleyball players. Eleven elite male volleyball players (90.3 ± 9.7 kg body mass and 1.94 ± 0.06 m height) were evaluated in an isokinetic dynamometer at speeds of 60, 180 and 300 deg/s. Muscle strength imbalances were obtained through calculation of contralateral deficit between limbs and the conventional ratio (hamstrings/quadriceps). Countermovement jump (CMJ) was performed on a force plate to calculate mechanical power and height. Association was found between knee extensor PT at 180 deg/s with CMJ power (r = 0.610, p = 0.046). Conventional ratio at 300 deg/s showed negative association with CMJ (r = −0.656, p = 0.029). The optimal ratio between knee extensors PT in relation to the flexors PT is associated with the greater mechanical power in CMJ. Contralateral deficit does not seem to be associated with the CMJ performance. Considering the knee extensor PT is associated with CMJ power, our findings suggest that strength-based training in volleyball athletes should not omit the conventional muscle ratio.

Background: Training load and adequate recovery have been identified as essential elements to improve well-being and performance in team sports and avoid non-functional overreaching and overtraining. Objective: This cohort study sought to analyze the stress and recovery perceptions, creatine kinase levels (CK), and vertical jump performance of volleyball athletes at different training times during a championship preseason. Methods: Thirteen high-level male volleyball players (23.80 ± 5.40 years, 91.50 ± 8.80 kg, and 193.10 ± 6.40 cm) completed the RESTQ-Sport questionnaire on stress and recovery perception, and blood samples were collected to evaluate CK levels. These measures were performed six times over 16 weeks, while jumps such as squat jump (SJ), countermovement jump (CMJ), and countermovement jump arm (CMJA) were performed at three of those times for specific performance evaluation. Results: The stress perception and recovery perception indices increased and decreased, respectively, in the pre-competitive phase, while CK levels presented an initial rise, maintenance over the training period, and a drop. Vertical jump heights increased significantly throughout the preparatory period regardless of the type of jump. In all training phases, CMJA values exceeded CMJ and SJ values, and CMJ values exceeded SJ values. Conclusions: Positive adaptations were elicited by training stimuli, resulting in improvements in performance. Conversely, load training variables indicated higher levels of stress and muscle damage, together with lower perceptions of recovery during the championship preseason.

For male soccer players, the anthropometric profile and physical performance is already known but in women it is not well documented, the knowledge of these differences can qualify the training. Therefore, the aim of this study was two-fold: (i) to compare the anthropometric profile and physical fitness of Brazilian professional female and male soccer players; and (ii) analyze the relationships between anthropometric and physical fitness measures per sex. A cross-sectional study including 92 professional soccer players 44 women and 48 men was conducted. After one week of the end of the pre-season, the players from four different teams were assessed to anthropometric profile assessments and physical performance tests (e.g., jumping, linear sprint, change-of-direction and aerobic based test). Comparisons, correlation, and effect size analysis were performed between groups. Apart from the age and change-of-direction test, all other anthropometric and physical performance variables were significant different between women and men. Men were significantly faster than women in the 20 m linear sprint test (8.87%; p < .001; d = 2.382). The sum of skinfolds was correlated with some physical performance variables; however, body mass and body height were corrected with physical performance only for female soccer players. Thus, men performed better than women for most physical tests and presents differences in the anthropometric profile. Finally, coaches should consider that the anthropometric and performance profile are correlated differently between female and male soccer players. Thus, coaches should consider gender-specific parameters to create goals about the anthropometric and physical performance profile of players.

The objective of the present study was to describe the total and fragmented external loads, at different intensities, of soccer referees in European and South American competitions during official matches through a systematic review and meta-analysis of cross-sectional studies. A systematic review was conducted in April, 2020. In all, 32 studies were included, incorporating 578 referees evaluated in 3170 games through video analysis or a global positioning system. Regarding external loads, it was observed that the total average distance covered by the referees was 10,461.74 m, with running speeds predominantly below 13 km.h^-1. The total distance covered by the referees in the European competitions was higher and more intense than that of the referees in the South American tournaments, being 11,187.02 m and 9319.61 m, respectively. We suggest that referees' training can be organized according to the distances found at different intensities, in which low-intensity races can be performed below 13 km.h-¹ with distances of approximately 4500 m, while high-intensity training can be developed with speeds from 18 to 24 km.h-¹ for approximately 800 m. In addition, planning must consider the competition characteristics.

The objective of this study was to identify parameters that best discriminate between selected and non-selected players for the Brazilian under-19 men’s volleyball team and propose mathematical models to identify high-performance players. To this end, 18 selected (16.89±0.96 years) and 138 non-selected (16.91±0.74 years) players for the under-19 team were assessed for the training profile, anthropometric profile, and physical performance level. The discriminant function analysis was used to build the models, with a significance of α<0.05. The spike jump reach showed a greater correlation with the discriminant scores obtained in the two models (r=0.701; r=0.782). The 10 variables included in Model 1 helped identify 88.9% of the players selected in their group of origin; Model 2 – obtained by the spike jump reach and duration of playing experience – identified 83.3% of the players selected. Therefore, coaches should be aware that differences between the selected and non-selected players are multi-factorial, with the spike jump reach being the most relevant assessment factor. Furthermore, good players for the selection can be identified using the two models: Model 1 promises greater success with ten assessments, whereas Model 2 allows the identification of suitable players for the under-19 men’s volleyball team with only two simple assessments.

The objectives of this study were: i) to analyze the sequence of game complexes in male youth volleyball categories, considering their frequency and effectivity of final actions, ii) to assess the importance of each complex within the overall game by the Social Network Analysis. We analyzed the behavior of 16 teams that participated in the Brazilian Selection Championship in 2019 in two levels (Special and First Division). The 56 games resulted in 200 sets, totaling 357,707 actions. We used the Fisher exact test, calculation of the significance of observation independence, and Social Network Analysis using eigenvector centrality. As result, there were fewer cases than expected for error in K0, continuity in KI and KV, and point in K0; there were more cases than expected for error in KI, continuity in K0, and point in KI and KV. The most frequent sequences of complexes and effectivity were K0E1-KIE2, K0E1-KIE0, K0E0, K0E2E2, K0E1-KIE1-KIIE2. The Eigenvector Centrality presented as results: KIIIE1, KIVE1, KV(2)E1, KIII(2)E1, KIII(3)E1 in the Special Division; KIII(3)E1, KIII(2)E1, KVE1, KV(2)E1, KIVE1 in the First Division. This study highlighted the main sequences, effectivity and differences that occurred in the Brazilian U-17 Male Selection Championship, assisting coaches in problem solving for training.