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Age-Related Reference Intervals for Physical Performance Test Outcomes Relevant to Male Youth Middle Eastern Football Players

Lorenzo Lolli, Warren Gregson, Daniele Bonanno, Sami Kuitunen, and Valter Di Salvo

Purpose: To develop age-specific reference intervals for physical performance test outcomes relevant to male youth Middle Eastern football players. Methods: We analyzed mixed-longitudinal data (observations range: 1751–1943 assessments) from a sample of 441 male youth outfield football players (chronological age range: 11.7–18.4 y) as part of the Qatar Football Association and Aspire Academy development program over 14 competitive seasons. Semiparametric generalized additive models for location, scale, and shape estimated age-specific reference centiles for 10-m sprinting, 40-m sprinting, countermovement jump height, and maximal aerobic speed variables. Results: The estimated reference intervals indicated that the distribution of the physical performance test scores increased monotonically and nonlinearly with advancing chronological age for sprinting and countermovement jump outcome measures, reaching a plateau after 16 years common to each of these performance variables. The maximal aerobic speed median score increased substantially until ∼14.5 years, with the nonlinear trend flattening off toward relatively older chronological ages. Conclusions: We developed age-related reference intervals for physical performance test outcomes relevant to youth Qatari football players. Country-wide age-specific reference intervals can assist in the longitudinal tracking of the individual players’ progress over time against benchmark values derived from the reference population.

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Exhaustive Intermittent Cycling Preferentially Decreases Explosive Over Maximal Voluntary Torque in the Knee Extensors, With No Difference Between Normoxia and Moderate to Severe Hypoxia

Olivier Girard and Sébastien Racinais

Purpose: To compare the effects of graded hypoxia during exhaustive intermittent cycling on subsequent rapid and maximal torque-production capacity. Methods: Fifteen well-trained cyclists repeated intermittent cycling bouts (15 s at 30% of anaerobic power reserve; rest = 45 s) until exhaustion at sea level (FiO2 ∼0.21/end-exercise arterial oxygen saturation ∼96%), moderate hypoxia (FiO2 ∼0.16/∼90%), and severe hypoxia (FiO2 ∼0.12/∼79%). Rapid (rate of torque development [RTD]) and maximal isometric torque-production capacities of the knee extensors were assessed at baseline (visit 1) and exhaustion (visits 2–4). Results: Exercise capacity decreased with hypoxia severity (39 [30], 22 [13], and 13 [6] cycle efforts in sea level, moderate hypoxia, and severe hypoxia, respectively; P = .002). Changes in maximal-voluntary-contraction torque between baseline and postexercise in all conditions were not statistically significant (pooled values: −2.6% [5.7%]; P = .162). Peak RTD measured postexercise was reduced below baseline in all conditions (–21.5% [5.1%]; P ≤ .015). Compared with baseline, absolute RTD values were lower at 0- to 30-millisecond (–35.1% [5.3%], P ≤ .020), 0- to 50-millisecond (–40.0% [3.9%], P ≤ .002), 0- to 100-millisecond (–30.7% [3.7%], P ≤ .001), and 0- to 200-millisecond (–18.1% [2.4%], P ≤ .004) time intervals in all conditions. Conclusions: Exhaustive intermittent cycling induces substantial yet comparable impairments in RTD of knee extensors between normoxia and moderate to severe hypoxia.

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Blood Lactate Responses of Male and Female Players Across an International Rugby Sevens Tournament

Carl James, James Rees, Henry Chong, Lee Taylor, Christopher M. Beaven, Mitch Henderson, and Julien S. Baker

Purpose: This study investigated within- and between-matches blood lactate (La) responses across an international Rugby Sevens tournament (5 matches over 2 d) in male and female players. Methods: Earlobe blood samples were taken from 25 professional players around matches: before warm-up (PRE), immediately upon finishing match participation (POST), and 30 minutes postmatch (30 min). Results: POST [La] (mean [SD], range) for males was 10.3 (3.2; 2.9–20.2) mmol·L−1 and for females was 9.1 (2.3; 3.4–14.6) mmol·L−1. Linear mixed-effects models revealed a decrease in POST [La] after match 5, compared to match 1. Increased PRE [La] was found before match 2 (+0.8 [0.6–1.1] mmol·L−1), match 3 (+0.8 [0.5–1.1] mmol·L−1), and match 5 (+0.6 [0.4–0.9] mmol·L−1) compared to match 1 (all P < .001). The [La] remained elevated at 30 min, compared to PRE (+1.7 [1.4–2.0] mmol·L−1, P < .001), with ∼20% of values persisting >4 mmol·L−1. Higher POST was observed in males compared to females (+1.6 [0.1–3.2] mmol·L−1, P = .042); however, no differences between sexes were found across 30 min or PRE [La]. No [La] differences between positions (backs and forwards) were identified. Conclusions: Lactate concentrations above 10 mmol·L−1 are required to effectively simulate the anaerobic demands of international Rugby Sevens matches. Practitioners are advised to individualize anaerobic training prescription due to the substantial variability observed within positional groups. Additionally, improving athletes’ metabolic recovery capacity through training, nutrition, and recovery interventions may enhance physical preparation for subsequent matches within a day, where incomplete lactate clearance was observed.

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Classifying Winning Performances in International Women’s Rugby Union

Georgia A. Scott, Ollie Edwards, Neil E. Bezodis, Mark Waldron, Eifion Roberts, David B. Pyne, Jocelyn Mara, Christian Cook, Laura Mason, M. Rowan Brown, and Liam P. Kilduff

Purpose: The efficacy of isolated and relative performance indicators (PIs) has been compared in rugby union; the latter more effective at discerning match outcomes. However, this methodology has not been applied in women’s rugby. The aim of this study was to identify PIs that maximize prediction accuracy of match outcome, from isolated and relative data sets, in women’s rugby union. Methods: Twenty-six PIs were selected from 110 women’s international rugby matches between 2017 and 2022 to form an isolated data set, with relative data sets determined by subtracting corresponding opposition PIs. Random forest classification was completed on both data sets, and feature selection and importance were used to simplify models and interpret key PIs. Models were used in prediction on the 2021 World Cup to evaluate performance on unseen data. Results: The isolated full model correctly classified 75% of outcomes (CI, 65%–82%), whereas the relative full model correctly classified 78% (CI, 69%–86%). Reduced respective models correctly classified 74% (CI, 65%–82%) and 76% (CI, 67%–84%). Reduced models correctly predicted 100% and 96% of outcomes for isolated and relative test data sets, respectively. No significant difference in accuracy was found between data sets. In the relative reduced model, meters made, clean breaks, missed tackles, lineouts lost, carries, and kicks from hand were significant. Conclusions: Increased relative meters made, clean breaks, carries, and kicks from hand and decreased relative missed tackles and lineouts lost were associated with success. This information can be utilized to inform physical and tactical preparation and direct physiological studies in women’s rugby.

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Performance Science Domains: Contemporary Strategies for Teams Preparing for the Rugby World Cup

Liam P. Kilduff, David B. Pyne, and Christian J. Cook

Purpose: As the start of the 10th Rugby Union World Cup approaches, performance staff will be working on the final elements of their teams’ preparation. Much of this planning and preparation will be underpinned by the latest performance science research. In this invited commentary, we discuss contemporary performance science research in rugby union centered around 4 key performance domains. First, we outline a systematic approach to developing an overall understanding of the game demands and how performance staff can enhance the players’ preparedness for competition. We then move on to outline our understanding of the training science domain, followed by a brief overview of effective recovery strategies at major tournaments. Finally, we outline research in the area of competition-day strategies and how they can positively impact players’ readiness to compete. Conclusions: Evaluating a team’s preparation for the Rugby Union World Cup can be achieved by mapping their performance plan based on the 4 domains outlined above.

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The Physical Preparation of Players for the Rugby World Cup

David B. Pyne, Christian J. Cook, and Liam P. Kilduff

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Erratum. Hematological Adaptations Following a Training Camp in Hot and/or Hypoxic Conditions in Elite Rugby Union Players

International Journal of Sports Physiology and Performance

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Change-of-Direction and Deceleration Deficits in National-Team Female Rugby Sevens Players: Interrelationships and Associations With Speed-Related Performance

Tomás T. Freitas, Lucas A. Pereira, Santiago Zabaloy, Pedro E. Alcaraz, Ademir F.S. Arruda, Valter P. Mercer, Chris Bishop, and Irineu Loturco

Purpose: To investigate the relationships between a series of direct and indirect measures of linear and multidirectional speed performance in elite female rugby sevens players. Methods: Nineteen players from the Brazilian national team performed 40-m linear sprint and 505 change-of-direction (COD) tests on the same day. Based on the linear sprint and COD test performances, the COD deficit (CODD) and deceleration deficit (DD) were also obtained. A Pearson product–moment correlation analysis was used to determine the relationships between linear sprint and COD-derived variables. Results: Linear sprint and 505 COD velocities were not significantly associated (P > .05). Large to very large significant associations (r values ranging from .54 to .78; P < .05) were detected between linear sprint velocity for the different distances tested (10, 15, 30, and 40 m) and CODD. The COD velocity presented a very large inverse significant correlation with CODD and DD (r = −.77 and −.79 respectively; P < .05). A large and significant correlation was identified between CODD and DD (r = .79; P < .05). Conclusions: Significant associations were observed between linear sprint and CODD, suggesting that faster players are less efficient at changing direction. No relationship was found between sprint velocity and DD, highlighting the independent nature of linear sprints and deceleration capabilities. A comprehensive and detailed analysis of multidirectional speed performance should consider not only linear sprint and COD performances but also complementary COD-derived variables such as the CODD and DD.

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Competitive Cross-Country Skiers Have Longer Time to Exhaustion Than Recreational Cross-Country Skiers During Intermittent Work Intervals Normalized to Their Maximal Aerobic Power

Eivind Holsbrekken, Øyvind Gløersen, Magne Lund-Hansen, and Thomas Losnegard

Purpose: To investigate differences in time to exhaustion (TTE), O2 uptake ( V ˙ O 2 ), and accumulated O2 deficit ( O 2 def ) between competitive and recreational cross-country (XC) skiers during an intermittent-interval protocol standardized for maximal aerobic power (MAP). Methods: Twelve competitive (maximal V ˙ O 2 [ V ˙ O 2 max ] = 76.5 ± 3.8 mL · kg 1 · min 1 ) and 10 recreational ( V ˙ O 2 max = 63.5 ± 6.3 mL · kg 1 · min 1 ) male XC skiers participated. All tests were performed on a rollerski treadmill in the V2 ski-skating technique. To quantify MAP and maximal accumulated oxygen deficit (MAOD), the skiers performed a steady-state submaximal test followed by a 1000-m time trial. After a 60-minute break, TTE, V ˙ O 2 , and accumulated O 2 def were measured during an intermittent-interval protocol (40-s work and 20-s recovery), which was individually tailored to 120% and 60% of each subject’s MAP. Results: During the 1000-m time trial, the competitive skiers had 21% (95% CI, 12%–30%) shorter finish time and 24% (95% CI, 14%–34%) higher MAP (all P < .01) than the recreational skiers. No difference was observed in relative exercise intensity (average power/MAP; P = .28), MAOD (P = .18), or fractional utilization of V ˙ O 2 max . During the intermittent-interval protocol, the competitive skiers had 34% (95% CI, 3%–65%) longer TTE (P = .03) and accumulated 61% (95% CI, 27%–95%) more O 2 def (P = .001) than the recreational skiers during work phases. Conclusions: Competitive XC skiers have longer TTE and accumulate more O 2 def than recreational XC skiers during an intermittent-interval protocol at similar intensity relative to MAP. This implies that performance in intermittent endurance sports is related to the ability to repeatedly recharge fractions of MAOD.

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A Systematic Review on the Physical, Physiological, Perceptual, and Technical–Tactical Demands of Official 3 × 3 Basketball Games

Pierpaolo Sansone, Daniele Conte, Antonio Tessitore, Ermanno Rampinini, and Davide Ferioli

Purpose: To systematically review the physical, physiological, perceptual, and technical–tactical demands of official 3 × 3 basketball games. Methods: The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were followed. Three electronic databases (PubMed, Scopus, and Web of Science) were systematically searched to identify studies assessing physical, physiological, perceptual, and technical–tactical demands of 3 × 3 games. Data were also coded according to player sex and tournament phase. Quality assessment of the included studies was performed using a modified Downs and Black checklist. Results: Thirteen articles were finally included, with a mean quality of 8.6 (1.1) out of 11. Three-by-three basketball games have an intermittent profile (1:1 work–rest ratio), with a duration of ∼15 minutes, and are characterized by short (6–8 s) ball possessions and considerable physical (17–33 accelerations, 24–44 decelerations, 62–94 changes of directions, and 17–24 jumps per game) and physiological (lactate: ∼6.2 mmol·L−1) demands. Overall, the game performance profile is similar in males and females, with minor changes happening across tournament phases. Several key technical–tactical indicators were identified as discriminating winning and losing teams, such as better shooting and defensive efficiency, low number of turnovers, and implementing tactical actions involving more players, passing first, and ending possessions with shots from outside of the arch from the top of the key. Conclusions: Three-by-three basketball is an intermittent, physically demanding sport characterized by quick plays and specific tactical constraints. This review provides information that should be considered by performance staff to improve training prescription, game tactical plans, and for player selection and talent identification.