International journal of sports physiology and performance最新文献

Purpose: The purpose of this research was to report isometric hip adduction and abduction strength reference values of men's and women's Gaelic football and rugby union players and compare values between sexes and between sports.

Methods: This cross-sectional cohort study consisted of 331 club-level athletes. Maximum isometric hip adduction squeeze and abduction press strength values were measured with a ForceFrame across several testing positions.

Results: Hip adduction squeeze and abduction press strength reference values for men's and women's Gaelic and rugby union footballers were provided with mean and 1 SD. A 2-way analysis of variance demonstrated significant sport × sex interaction main effects for hip adduction squeeze (η2 = .159-.228), abduction press (η2 = .099-.144), and adduction:abduction ratio (η2 = .120). Men demonstrated significantly greater relative (Newtons per kilogram) maximum isometric hip adduction squeeze (15.5%-26.4%, 0.48-1.00 N/kg) and hip abduction press (9.6%-19.6%, 0.20-0.67 N/kg) strength across all testing positions when compared with women of the same sport. Male Gaelic football players demonstrated significantly greater hip adduction (8.7%-14.0%, 0.30-0.52 N/kg) and abduction (6.1%-8.6%, 0.16-0.31 N/kg) strength (Newtons per kilogram) than their rugby counterparts, while no significant between-sports differences in strength were observed between female athletes.

Conclusion: Reference values are provided with mean and 1 SD. Sport and sex interaction had significant main effects for hip adduction, abduction, and adduction:abduction ratio, with medium to large effect sizes. Male athletes demonstrate significantly greater hip strength than female athletes of the same sport, and male Gaelic players demonstrate greater hip strength than male rugby players.

Purpose: Previous research has primarily focused on bounce drop jump (BDJ) rather than countermovement drop jump (CDJ) in studying optimal drop heights for drop jump. This study explored the biomechanic parameters of both BDJ and CDJ and their relationship with performance across varying drop heights based on the percentage of squat-jump height (SJH).

Methods: Twenty-four college basketball athletes were recruited and divided into low- and high-strength groups. Participants performed BDJ and CDJ at 50%, 75%, 100%, 125%, 150%, and 175% of SJH. The point or zone with the largest reactive strength index (RSI) corresponds to the optimal drop height for a drop jump.

Results: Optimal drop heights were determined to be 84.7% of SJH for BDJ low strength and 84.1% of SJH for BDJ high strength, with no significant difference between groups (P = .213). For CDJ, relative optimal drop heights were 104.6% of SJH for CDJ low strength and 106.1% of SJH for CDJ high strength, also with no significant difference (P = .717). Mechanical power with RSI exhibited a coefficient close to 1 (r = .98-.99), while average propulsive force demonstrated a very strong positive correlation with RSI (r = .72-.77).

Conclusions: It is recommended that basketball athletes incorporate particular percentages of SJH into drop jump, with 75% to 100% of SJH for BDJ and 100% to 125% of SJH for CDJ, as these heights are associated with achieving an optimal RSI and mechanical power. Tailoring the inclusion of BDJ or CDJ in training should account for the specific demands of on-court positions and task objectives for basketball players.

Purpose: Confirmation bias, a cognitive phenomenon deeply ingrained in human thinking, shapes our perception of reality. It leads individuals to favor information that aligns with their preexisting beliefs while dismissing or undervaluing the contrary evidence. In sport science, where precision and evidence-based practices are critical aspects to optimize performance, confirmation bias can decisively impact decision-making processes. In this context, practitioners rely on both objective and subjective data to be interpreted to enhance athletic performance. However, confirmation bias introduces a subtle yet powerful distortion, which is difficult to control and quantify. We usually believe that our observations can justify expectations or predictions about future observations, as well as broader generalizations beyond what we have directly observed-inductive inferences. Researchers and practitioners may therefore unknowingly seek out evidence that confirms their beliefs, inadvertently overlooking alternative viewpoints and interpretations.

Conclusions: This paper explores the concept of confirmation bias in sport science, providing practical examples in the contexts of testing, training, and monitoring. By understanding how confirmation bias operates (ie, heuristic of decision making), we may develop strategies to mitigate its effects and promote more accurate and effective decision making in sport science (eg, performance).

Purpose: Although women's futsal has experienced great growth recently, few studies have analyzed the physical profiles of female futsal players. The objectives of this study were to determine the physical and anthropometric characteristics in elite women's futsal using laboratory and field tests and to analyze the differences between the different playing positions.

Methods: Forty-one female futsal players from the second division of the Spanish league (age 22.69 [4.76] y; body height 161.28 [6.03] cm; body mass 62.20 [10.34] kg) were evaluated for body composition with dual-energy X-ray absortiometry anthropometrically, lower-body power using a force platform (countermovement jump, squat jump, and drop jump), linear speed (5, 10, 15, and 25 m), changes of direction (505 modified, V-Cut, and L-Run), and repeated-sprint ability measured through photoelectric cells.

Results: The results reveal that there are no significant differences between the physical profiles of players depending on playing position. Despite this, wingers seem to have the best physical profiles, and goalkeepers have the highest body mass index (26.9 [4.48] vs 23.3 [2.82]; P = .069) and fat percentage (31.9 [7.81] vs 29.96 [6.08]; P = .101), but they present very similar values to the other positions in all other tests performed, except for repeated-sprint ability (4.64 [0.45]; P = .009).

Conclusion: Relevant descriptive data were presented to provide useful information for coaches to optimize their training programs, reporting that playing position does not identify different physical profiles in elite female futsal players.

Purpose: The present study analyzed the effects of a maximal-power-endurance (MPE) versus a repeated-power-ability (RPA) training program on different strength, power, and repeated-power measurements in a short- and long-term training period and the relationships between changes in all variables.

Methods: Twenty-two young highly trained male basketball players were randomly allocated to 1 of the 2 groups (MPE, n = 11; RPA, n = 11) and evaluated by 1-repetition maximum and incremental load, RPA, and MPE tests in the bench-press exercise before and after a period of 4 and 8 weeks. The MPE group performed 2 to 4 sets of a postdetermined number of repetitions (ie, set stopped when maximum power output decreased >10%) using the load that maximized power output. The RPA group carried out 1 to 3 blocks of 5 sets of 5 repetitions with a load that maximized power output.

Results: Both groups significantly (P < .001; effect size = 0.58; 1.56) improved 1-repetition maximum, maximum power output, and 20%, 40%, 60%, and 80% of 1-repetition maximum from pretest to posttest in the incremental load test. Significant improvements (P < .001) were found for the RPA and MPE groups in the best, mean, and last set in the RPA test at all times. Furthermore, a significant (P < .001) time × group interaction was found in the MPE test, showing significant improvements in both groups at posttest. In addition, at posttest, intraset power fluctuation in the mean was significantly (P < .05; effect size = 0.45) better in MPE group compared with RPA group.

Conclusion: In conclusion, both training programs represent appropriate methods to improve neuromuscular measurements, although MPE training seems to be a more volume-efficient strategy (∼50% fewer repetitions) to enhance several fatigue-resistance indexes (intraset power fluctuation in the mean).

Purpose: Pacing is crucial in endurance sports such as running, and its importance is also prominent in trail running due to the unique challenges, including high elevation gains and varied terrain. This study aimed to explore the pacing strategies of elite athletes during the 2023 World Mountain and Trail Running Championships for the Trail Short distance.

Methods: The participants included 12 elite trail runners who provided their race data from sport watches for analysis.

Results: The findings indicate a significant decrease in grade-adjusted pace (vi) as the race progressed, with an average change of -18.7% from the start to the last downhill segment. A linear correlation of -.55 (P = .031) was observed between the winning time and the evolution of vi, suggesting that more consistent pacing led to better performance. The Student t test (t = 2.628, numerator degrees of freedom = 10, P = .013) confirmed that even pacing is significantly correlated with superior race results at a confidence level above 95%.

Conclusions: A more even pacing strategy is associated with success during elite trail-running races.

Purpose: This study aimed to (1) classify the external-load measures carried out during the preseason period by male volleyball players via cluster technique identifying the most important external-load measures and (2) assess the differences between clusters in internal-load variables.

Methods: Twenty-two male Division 1 and 2 volleyball players (mean [SD] age 21.2 [3.0] y, stature 186.4 [6.0] cm, body mass 80.0[10.5 kg]) were recruited for this study. Players' external (jump, player load, acceleration, deceleration, and change of direction) and internal (percentage of peak heart rate, summated heart-rate zones, and session rating of perceived exertion) loads were monitored during 5 weeks of the preseason period for both Division 1 and Division 2 teams. External-load measures were classified via a 2-step cluster analysis followed by predicting importance analysis, while differences in internal-load measures between clusters were analyzed using linear mixed models.

Results: The 3 identified clusters classified the sessions in high (C1, 30.1%) moderate (C2, 31.8%), and low (C3, 38.1%) load. Predicting importance analysis found jump as the main cluster predictor (predicting value = 1), followed by player load (predicting value = 0.73). An effect of cluster was found on each internal-load measure (P < .001), with post hoc analyses showing lower values in C3 compared with C1 and C2 (P < .05, effect sizes ranges from small to moderate).

Conclusions: Volleyball coaches can adopt a monitoring system including cluster analysis to classify the preseason training sessions' load having a higher consideration for jump and player load as the main external-load measures.

Purpose: To analyze tactical behaviors associated with performance in track middle-distance global championship finals.

Methods: Finalists' season-best finishing race time, 100-m section times, and intermediate positions were obtained from 800- and 1500-m men's and women's finals in 2 Olympic Games and 5 World Championships. Differences between medalists, fourth- to eighth-ranked (T8), and ninth- to 12th/13th-ranked finalists in relative performance (relative to season-best), race time, and section times were determined. Pearson correlations between intermediate position and section speed with final position and probability of winning a medal at each race point were calculated.

Results: A very high correlation was found between intermediate and final position at the first 100 m in the women's 800-m (r = .84; P = .008), which was maintained throughout the race. Medalists were relatively faster than T8 in men's and women's 800-m finals (P = .006; d = 0.87, and P = .039; d = 0.59, respectively). Differences in relative performance between groups in 1500-m finals appeared at the end of the race, although they arose earlier in women's races. The probability of winning a medal decreased with lower intermediate positions, especially in the latest race stages.

Conclusions: A high intermediate position, as well as the ability to run fast in the latest race stages, seems critical to medaling in track middle-distance global championship finals. The abilities to adopt leading positions for the whole 800-m event and to generate an end spurt relatively faster than the rest of competitors in the 1500-m event are critical.

Iron and vitamin D are essential for physiological mechanisms underpinning physical capacities characterizing team-sport performance. Yet, the impact of iron deficiency on physical capacities beyond endurance is not clear.

Purpose: The purpose of this study was to assess variations in seasonal micronutrient concentrations and how iron deficiency impacts external-load measures in elite female rugby league players.

Methods: Iron and vitamin D status were measured in 28 players (age 24 [4] y, body mass 76 [11] kg) across 3 time points of the 17-week National Rugby League Women's season. Physical demands were evaluated using external-load measures (eg, total distance, PlayerLoad) for training and competition. Linear mixed-effects models were employed to assess the effect of change in serum ferritin concentration on external-load measures. Effect sizes with 95% CIs were calculated to interpret the magnitude of difference in change in indices and performance outcomes between iron-deficient and iron-sufficient players.

Results: Iron-deficiency prevalence ranged from 26% to 57% across the season, and <22% of players were vitamin D deficient at each time point. Weak to strong positive associations (R2 = .3-.6) were observed between all external-load measures and moderating variables (serum ferritin, week, position, and athlete). However, these associations were largely attributable to the contribution of week and position. Differences in load measures between iron-deficient and iron-sufficient players were mostly trivial to small.

Conclusions: Iron status of elite female rugby league players had little effect on most workload measures within this cohort. However, longitudinal monitoring is warranted to identify how external-load measures are affected individually in response to fluctuations in serum ferritin.