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A Comment on González et al: Predicting Injuries in Elite Female Football Players With Global-Positioning-System and Multiomics Data

Lorenzo Lolli

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Response to Lolli: Predicting Injuries in Elite Female Football Players With Global-Positioning-System and Multiomics Data

Juan R. Gonzalez and Gil Rodas

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Strategic Analysis of Net Exchanges in Professional Padel: Insights From Different Competition Phases of the World Padel Tour Finland Padel Open Tournament

Adrián Escudero-Tena, Rafael Conde-Ripoll, Corrado Lupo, and Alexandru Nicolae Ungureanu

Purpose: This study analyzed the effectiveness of net exchanges (ie, number of times the pairs exchange their zone on the court from the net zone to the back zone or vice versa) in men’s and women’s professional padel depending on the competition phase. Methods: Data were collected from 41 matches, comprising a total of 4829 points, from both the qualifying and the main draws of the World Padel Tour Finland Padel Open tournament. Descriptive analysis (frequency and percentage) and inferential tests (Pearson chi-square [χ 2], Cramer V coefficient [Vc], corrected standardized residuals, and chi-squared automatic interaction detection) were carried out. Results: There were significant differences (P < .05) in net exchanges between the main and qualifying draws, both in men’s (79.6% vs 72.1% for no exchanges) and women’s (62.2% vs 57.6% for no exchanges) padel. Additionally, differences in the likelihood of winning points based on whether the serving pair or the returning pair finished the rally at the net were highlighted. Indeed, finishing rallies at the net for the serving pairs increased the probability of scoring a winning shot (ie, in even-numbered net exchanges), while finishing rallies away from the net (ie, in odd-numbered net exchanges) was more likely to result in errors, for both male and female players and main and qualifying draws. Conclusion: This study provides valuable insights into the strategic behavior of professional padel matches, highlighting the importance of net dominance and its impact on match outcomes, particularly in relation to gender differences and phase of competition.

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Effects of the Birthplace Altitude and Training Volume on Hematological Characteristics in Youth and Junior Male Colombian Cyclists

Erica Mancera-Soto, Mauricio Garzon, Alain S. Comtois, and Grégoire P. Millet

Purpose: The long-term development of talent in endurance sports is a topic of interest. Among various factors, the importance of total hemoglobin mass (tHbmass) and the potential benefits of being an altitude-native athlete remain unclear, particularly in young categories. This study aimed to investigate the impact of altitude and training content on hematological characteristics by comparing young male cyclists age 15–16 and 17–18 years who were born and trained at a moderate altitude (ie, greater than or equal to 2500 m; MA) and cyclists who were born and trained at low altitude (below 1000 m; LA). Methods: tHbmass (in grams and grams per kilogram), measured by using the optimized carbon monoxide rebreathing method during an incremental test on a cycle ergometer; hematocrit percentage, hemoglobin concentration; and erythrocyte, blood, and plasma volume were measured in youth male cyclists age 15–16 years and junior cyclists age 17–18 years who were born and trained at MA versus LA. All variables were analyzed with a 2-way (age [youth cyclist vs junior cyclist] × altitude level [MA vs LA]) analysis of variance with subsequent Tuckey post hoc test. Results and Conclusion: Some altitude-induced benefits were reported in cyclists at age 15–16 years in the MA group with higher values in hematocrit percentage, hemoglobin concentration, and tHbmass (grams per kilogram) (P < .05) than their LA counterparts. This was also observed at age 17–18 years (P < .001), except for tHbmass, wherein no significant difference was found between MA and LA groups. In contrast, plasma volume was lower in MA than LA junior cyclists. New Findings : (1) The altitude of birth and residence could generate an advantage in tHbmass in young male cyclists age 15–16 and 17–18 years who train at MA compared with cyclists who are born and train at LA. (2) Altitude-induced benefits in physiological variables (hematocrit percentage, hemoglobin concentration, tHbmass in g·kg−1) were reported in cyclists at age 15–16 years and partially at age 17–18 years. In contrast, plasma volume was lower in MA than in LA junior cyclists. This may impact the strategies for identifying and developing talent in cycling.

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Isometric Midthigh-Pull Testing: Reliability and Correlation With Key Functional Capacities in Young Soccer Players

Vincenzo Rago, Fábio Yuzo Nakamura, Carlos Suarez-Balsera, Javier Arnaiz-Lastras, and Pedro Figueiredo

Purpose: We examined the reliability of force parameters derived from the isometric midthigh pull (IMTP) and their correlation with the functional capacities of young soccer players. Methods: Data were collected from 20 young professional soccer players within and between 2 sessions (after 1 wk) using a 1000-Hz force plate. Results: Performance outputs in all IMTP parameters were consistent and showed moderate to excellent reliability (intraclass correlation coefficient = .72–1.00) within and between sessions. However, all parameters reported a marginal ability to detect chronic changes in performance (smallest worthwhile change [SWC] < standard error of measurement [SEM]) except for peak vertical force (PF) parameters, which showed good usefulness (SWC > SEM). Absolute PF was correlated with the countermovement-jump (CMJ) total impulse (CMJ-TI; r = .54), whereas relative PF (to body mass) was correlated with CMJ height, CMJ peak power, and the last speed of the 30:15 Intermittent Fitness Test (V IFT; r = .40 to .63). IMTP time-dependent forces were correlated with CMJ-TI (r = .52 to .62). The IMTP impulse parameters were positively correlated with CMJ-TI (r = .48 to .58) and negatively with V IFT (r = −.44 to −.38). None of the IMTP parameters were correlated either with the CMJ mean propulsive force or with any linear acceleration times. Conclusions: All IMTP parameters can be adopted by practitioners involved with testing young soccer players based on their acceptable reliability criteria. However, caution should be taken when interpreting the time-dependent variables based on their marginal usefulness when assessing performance. Generally, a greater PF was associated with a greater vertical power based on its correlation to CMJ.

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Sensitivity of Minimally Invasive Protocols to Monitor Changes in Endurance Performance in Elite Junior Football (Soccer) Players

Jan Schimpchen, Paulo F. Correia, and Tim Meyer

Purpose: Adequate physical fitness is a key requirement for elite footballers. Maximal fitness tests are the standard for evaluating fitness but are often fatiguing and time consuming. This study investigated the ability of various minimally invasive protocols to reflect changes in standard parameters of football players’ physical fitness. Methods: Twenty-one elite junior footballers performed 2 standard fitness tests (stepwise incremental treadmill test with blood-lactate and heart-rate [HR] measurements and Yo-Yo Intermittent Recovery 1 test) and various proxy fitness evaluations (submaximal runs with measurement of exercise HR and HR recovery and external-to-internal load ratios with data collected during match play) 3 times over the course of 19 weeks. Changes in the standard parameters were compared with changes in proxy parameters. Results: Changes in maximal endurance performance showed small to moderate associations with HR-based proxy parameters (r = −.1 to −.46; P = .004–.56), whereas changes in the running velocity at anaerobic threshold had trivial to moderate associations (r = −.07 to −.39; P = .01–.67). Alterations in HR recovery following 2 short, submaximal runs were very largely correlated with changes in the running velocity corresponding to an HR of 170 beats·min−1 (r = −.74 and r = –.75; P < .001). Changes in external-to-internal load ratios derived from match play were not significantly correlated with changes in any of the standard parameters (r = −.03 to .31; P > .05). Conclusions: Parameters of maximal running performance and parameters describing physiological thresholds do not seem to be adequately captured by different minimally invasive protocols. In contrast, HR recovery following short, submaximal runs may be a valid tool to monitor changes in aerobic endurance adaptations.

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Comparing the Effects of Aqua- and Land-Based Active Cooldown Exercises on Muscle Soreness and Sport Performance: A Randomized Crossover Study

Edwin Chun-Yip Chin, Steve Chung-Nam Lai, Sau-Fung Tsang, Sam Ho-Ngai Chung, Yik-Long Wong, Navjot Sran, Kwok-Keung Fung, and Fenghua Sun

Objective: Limited research has directly compared the effectiveness of aqua- and land-based exercises for postexercise recovery. This study aimed to fill this gap by comparing the effects of these 2 types of exercises on postexercise recovery. Methods: Sixteen male college athletes participated in an 8-day experimental study. The initial 2 days were dedicated to determining the intensity levels for the muscle-damaging exercise and recovery jogging. In a crossover design, participants underwent 2 sets of experimental trials. They were randomly assigned to either an aqua or land recovery intervention for days 3 to 5, and after a 1-week washout period they switched to the opposite intervention for days 6 to 8. Muscle soreness, creatine kinase, anaerobic performance, countermovement-jump height, and flexibility were assessed at different time points: baseline, immediately after downhill running, within 1 hour after jogging, and 24 hours and 48 hours after aqua or land jogging. Results: Significant group × time interaction effects were detected in the perceived soreness of the hamstring and quadriceps. However, the post hoc analysis showed no significant difference between aqua and land jogging groups. No significant group × time interaction effect was observed in creatine kinase, anaerobic performance, countermovement-jump height, or flexibility. Conclusion: Aqua and land jogging have similar recovery effects on muscle soreness and performance-based parameters.

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Assessment of the Relationship Between Physical Performance and Percentage Change-of-Direction Deficit in Highly Trained Female Football Players

Alberto Roso-Moliner, Elena Mainer-Pardos, Chris Bishop, and Oliver Gonzalo-Skok

Purpose: Different studies indicate that female players in team sports such as soccer tend to have a lower change-of-direction (COD) deficit (CODD) than their male counterparts and that players who performed better in linear and curved sprints tended to have a worse CODD, suggesting that maximum speed does not equate to a faster COD. This study assessed how performance variables related to speed and jumping influence the variability of %CODD among adult highly trained female soccer players. Methods: Fifty-two highly trained female soccer players (age 23.1 [3.25] y; height 163.6 [5.49] cm; weight 59.7 [5.71] kg) participated in this study and performed 180COD, 40-m sprint, countermovement jump, and standing broad jump tests. Results: Significant correlations were found between 180CODL, %CODDR, %CODDL, and between-limbs standing broad jump asymmetry (r = .28–.74). A very large correlation existed between %CODDR and %CODDL (r = .91). Regression analyses indicated a strong inverse relationship between the 10-m sprint time and %CODDR and %CODDL. No predictive models were found for 180COD in either limb. Differences in performance variables such as 180CODR, 180CODL, and asymmetry %CODD were significant between the high- and low-%CODD groups, with moderate to large effect sizes. Conclusion: The present study suggests that specific physical-performance variables, particularly acceleration and unilateral horizontal jumping, are vital to improving COD in highly trained female soccer players, highlighting the need for specific training interventions.

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Observation of the Achilles Tendon and Gastrocnemius Muscle’s Passive Stiffness During an Incremental Running Protocol

Anh Phong Nguyen, Laurent Bosquet, Laureen Cugnet-Evans, Christine Detrembleur, and Philippe Mahaudens

Objective: Passive stiffness, a biomechanical parameter, has a potential influence on running economy, thus playing a pivotal role in performance. This study aimed to quantify passive stiffness of the Achilles tendon and gastrocnemius muscle using myotonometry throughout an incremental running protocol. Methods: Twenty-one male participants underwent a multistage incremental test (Bordeaux test) on a treadmill until exhaustion. Passive stiffness of the gastrocnemius muscle and Achilles tendon was measured using a MyotonPRO device. Measurements were taken before, during, and after the incremental test. Results: Our findings indicated that passive stiffness of the medial gastrocnemius decreased at rest between prerun and postrun assessments (−20.12 N·m−1, P = .012). Furthermore, during the test, stiffness increased at low intensity (at 50% of maximal aerobic speed: +104.8 N·m−1, P = .042), returning to baseline values as intensity increased. Conclusions: Throughout an incremental running protocol, both Achilles tendon and gastrocnemius muscle stiffness initially increased and then decreased with escalating percentages of maximal aerobic speed. A deeper understanding of stiffness in running can inform more effective recommendations for runners’ strengthening and training.

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University Rankings in Sport Science: A True Reflection of Excellence?

Ivana Matic Girard and Olivier Girard

Background: University rankings often serve as benchmarks for excellence in academic evaluation. For example, ShanghaiRanking data from 2016 to 2023 for the Global Ranking of Sport Science Schools and Departments reveal consistent dominance by Australia (23.1%), Canada (18.0%), and the United States (12.0%), collectively counting over half of the top 50 universities worldwide. Nevertheless, there is uncertainty about how the methodology behind these rankings shapes a reality as much as it reflects one. Purpose: Our intention is to discuss the complexity of university rankings, using ShanghaiRanking as an example, to highlight how these rankings reflect academic excellence within the field of sport science. Current Evidence: When ranking universities in sport science, several aspects of academic excellence could be considered in addition to research metrics currently considered in ShanghaiRanking (publication, citation, citations per publication, top 25% journal publications, and internationally collaborated publications). These aspects may include (1) teaching quality, (2) practical training, (3) industry links and employability, (4) support services, (5) facilities and equipment, (6) international network, (7) community engagement, (8) sustainability and ethical practices, and (9) interdisciplinary approach. Altogether, they could provide a more comprehensive view of the quality and effectiveness of a sport-science program. Conclusions: The ranking of sport-science institutions poses a complex challenge due to diverse factors influencing academic excellence. Engaging in a broader dialogue and refining internationally relevant evaluation methodologies are crucial. These steps enable comparability between countries and provide a holistic understanding of the multidimensional nature of academic excellence in sport science.