International journal of sports physiology and performance最新文献

Purpose: To investigate the effects of running repeated-sprint training with voluntary hypoventilation at low lung volume (RSH-VHL) including prolonged end-expiratory breath holding (EEBH) on running repeated-sprint ability (RSA).

Methods: Twenty semiprofessional male soccer players completed 12 sessions of repeated 50-m running sprints over a 6-week period either with EEBH (RSH-VHL, n = 10) or with normal breathing (RSN, n = 10). Before (Pre) and after (Post) training, a running RSA test consisting of performing maximum 30-m "all-out" sprints until task failure, with a minimum of 10 sprints, was implemented.

Results: The maximum number of sprints was increased at Post compared to Pre in RSH-VHL only (13.5 [4.4] vs 7.7 [2.3], P < .01) and was greater in RSH-VHL than in RSN at Post (P < .01). The mean velocity for sprints 1 to 10 and sprints 6 to 10 was increased in both groups at Post (P < .01) but was greater in RSH-VHL than in RSN after the training period (P < .01). There was no change in the reference velocity (P = .80) or in the maximal velocity reached during the RSA test (P = .52) in either group. The mean minimal arterial oxygen saturation recorded during training at the end of the sprints was lower in RSH-VHL (78.5% [1.4%]) than in RSN (97.3% [0.1%]).

Conclusions: This study shows that an RSH-VHL intervention including prolonged EEBH can provide an additional benefit for improving RSA in male semiprofessional soccer players. This result may be due in large part to the strong hypoxic effect induced by the prolonged EEBH.

Purpose: This study aimed to investigate differences in match physical and technical/tactical performance of teams across different competitive levels in international soccer: FIFA Men's World Cup Qatar 2022 (MWC), FIFA U20 World Cup Argentina 2023 (U20WC), and FIFA U17 World Cup Indonesia 2023 (U17WC).

Methods: From a total of 168 games, 138 games were analyzed (N = 276 game observations) using an optical tracking system.

Results: On average, the U17WC teams exhibited reduced total running (3% less), high-intensity running (14%-16% less), and sprinting (18%-26% less) distance than the MWC and U20WC teams (P ≤ .0023; effect size [ES]: 0.8-1.5). The MWC teams displayed 4% to 5% higher accuracy in passing and executing line breaks (P ≤ .0188; ES: 0.6-0.7), along with increased offers to receive the ball (53%-118% more) and movements to receive the ball (44%-101% more), and received the ball (61%-137%) more often than the U20WC and U17WC teams (P < .001; ES: 1.1-2.1). Moreover, notable decreases in defensive pressure (-18% to -32%) and forced turnovers (-26% to -32%) were observed in the U17WC than other competitions (P ≤ .0001; ES: 0.8-2.2). Greater variability was observed among the U17WC teams in several metrics, including high-intensity/sprinting distances, attempts at goal, and receptions in the final third.

Conclusions: These findings demonstrate that as the competitive level increases, so do the physical demands, advanced technical skills, and tactical fluidity/adaptability. However, caution should be exercised when interpreting match performance of younger age groups, as higher variability was evident in both physical and technical/tactical performance in matches.

Purpose: To explore the influence of menstrual phase on postmatch perceptual responses and the time course of recovery for professional footballers.

Methods: Thirteen naturally menstruating footballers tracked their menstrual cycle and reported perceptual responses for up to 4 cycles. Menstrual phases were determined by calendar-based tracking and urinary hormone tests and classified as menstruation, follicular, or luteal. On match days (MDs) and the following 2 days (MD+1 and MD+2), players completed perceptual questionnaires on fatigue, soreness, stress, sleep, and perceived recovery status (PRS). Total high-speed running distance during matches was recorded using GPS devices to represent load. Data were analyzed using linear mixed models.

Results: Day × total high-speed running distance affected PRS (P < .001), total wellness (P < .001), fatigue (P = .047), soreness (P < .001), and stress (P = .044). Significant main effects were found for menstrual phase on PRS (P = .038), Day on stress (P = .034), and total high-speed running distance on soreness (P = .045). During the menstruation phase, moderate effect sizes (ES) existed for worse PRS on MD and MD+2 (P = .07-.28, ES > 0.51) and better sleep quality on MD+2 (P = .13, ES = 0.56). No significant differences between menstrual phases existed (P > .05), and all other ESs were trivial to small (ES < 0.50). All perceptual measures, except stress, differed significantly between days (P < .05), with differences based on match load and, to a lesser extent, menstrual phase.

Conclusion: PRS may be worse during menstruation, although menstrual phase has limited association with postmatch perceptual responses. Variability in the recovery time course for perceptual measures exists between menstrual phases, but evidence for consistently impaired recovery time course in any phase was not evident.

Purpose: To evaluate the within-athlete sensitivity, validity, and dose-response relationships of exercise heart rate (HRex) from a submaximal fitness test (SMFT) as a proxy measure of cardiorespiratory fitness.

Methods: This study follows an observational, repeated-measures design. Twenty-five trained female football players' training loads (GPS and HR metrics) were collected throughout an 8-week preseason period. A 4-minute continuous-fixed SMFT protocol was administered weekly to evaluate HRex. A running time-trial assessment was conducted in weeks 2 and 8 to calculate mean velocity (5-min-30-s time-trial mean velocity) as a proxy measure of cardiorespiratory fitness. SMFT HRex measurement properties were determined via within- and between-athletes correlations and linear mixed models.

Results: The overall preseason change in SMFT HRex derived from weekly repeated measures was -4.7% points (90% CIs, -3.9 to -5.6). The association between SMFT HRex and 5-minute-30-second time-trial mean velocity changes was large (-0.55), with 90% CIs ranging from negative moderate to negative very large magnitudes (-0.31 to -0.71). A 1% point decrease in SMFT HRex corresponded to an increase in 5-minute-30-second time-trial mean velocity of 0.13 (90% CIs, 0.03-0.24) km·h-1. Within-athlete correlations between training loads and SMFT HRex demonstrated moderate inverse relationships with external-load parameters (-0.39 to -0.47) and small inverse relationships with HR-based internal metrics (-0.25 to -0.29). Accumulated high- and very high-speed running throughout the entire preseason showed consistent inverse dose-response relationships with SMFT HRex (moderate and large, respectively), while all other load measures displayed unclear associations.

Conclusions: SMFT HRex is a sensitive and valid tool to evaluate preseason cardiorespiratory-fitness changes in female football players.

Background: Sport scientists aim to enhance athletic performance by developing, implementing, and evaluating evidence-based strategies. However, a common challenge to maximize sport science's impact is the limited involvement of "research end users" (ie, athletes, coaches, and practitioners) in contextualizing these strategies. To address this, research-embedded training camps (RETCs) offer a collaborative opportunity bringing together all stakeholders to tackle real-world challenges by blending scientific insight with practical application for better knowledge translation or production.

Purpose: This invited commentary explores the behind-the-scenes aspects of conducting successful RETCs. We discuss opportunities and challenges involved, drawing on our practical experience with environmental stress interventions.

Evidence: Implementing an RETC requires a tailored intervention, shaped by the athlete group, research questions, and available resources-essentially answering the who, what, why, when, and where questions. Key principles for success include an athlete-centered focus, a diverse multidisciplinary team, scientific rigor, balancing control with flexibility, and adaptability. A coconstructed design ensures that the intervention remains scientifically relevant and practical and directly addresses real-world needs of athletes.

Conclusion: Through the lens of environmental stress interventions, RETCs should prioritize practicality, collaboration, and athlete-focused approaches. Conducting interventions with athletes rather than on them can significantly enhance performance and support evidence-based training strategies (knowledge translation) and/or provide new actionable insights (knowledge production).

Purpose: To compare the frequency and severity of self-perceived negative symptoms associated with the menstrual cycle or hormonal-contraceptive (HC) cycle between (1) HC users and non-HC users and (2) different competition levels. An additional aim was to describe the rate and type of HC use and prevalence of potential menstrual-cycle disturbances in female team handball players.

Methods: A total of 136 team handball players, competing at different levels (international, 48; national, 52; local/regional, 36), completed a cross-sectional survey regarding self-reported negative cycle-related symptom frequency and severity, perceived influence on training/competition performance, menstrual function, and current and/or past HC use.

Results: Although most players regularly experienced negative cycle-related symptoms, non-HC users reported more frequent and severe cramps (P = .001 to .026), as well as a higher occurrence of fatigue and skin problems (P = .019 to .045), compared with HC users. Negative symptoms such as fatigue were more common and severe for local/regional-level players compared with players at higher (international) competition levels (P = .006-.046). Half (47%) of the players currently used HC, primarily long-acting reversible contraceptives (52%), as well as the combined oral (33%) or progestin-only pill (14%). Notably, only 2% of players altered their training in response to negative cycle-related symptoms, despite 41% perceiving that these symptoms interfered with training quality and athletic performance.

Conclusions: Negative cycle-related symptoms are common among team handball players, regardless of HC use, and are perceived by many players to adversely influence their athletic performance.

Predictions of performances should be evaluated to confirm their accuracy. Work by this group has resulted in 3 sets of predictions being generated for swimming events at the Paris 2024 Olympic Games, using the same statistical approach for each set.

Purpose: To examine the accuracy of swimming predictions for the Paris 2024 Olympic Games and generate updated predictions for both the Singapore 2025 World Aquatics Championships and Los Angeles 2028 Olympic Games.

Methods: A linear regression and forecasting function was used to generate predictions for the Paris 2024 Olympic Games across 3 performance categories (rank 1st-3rd, 4th-8th, and 9th-16th). Mean absolute error was used to assess the accuracy of the predicted versus actual Paris 2024 Olympic Games times for all events across the 3 performance categories. New predictions for the 2028 Olympic cycle were subsequently generated using results from the World Championships and Olympic Games between 2011 and 2024.

Results: Across all events, a mean absolute error value of 0.84% was observed between the Paris 2024 Olympic Games predicted and actual times. Predicted times were highly correlated with actual times (r2 = .99). Across the 3 sets of predictions (created in 2022, 2023, and 2024), the 2023 set of predictions had the lowest overall mean absolute error value (0.55%).

Conclusions: The methods used to create predictions for swimming performances at the Paris 2024 Olympic Games were deemed accurate. These methods enable national swimming federations to create a series of predictions for a given major championship, inform athlete identification and development pathways, and allocate appropriate resources, including sport-science provision.

Background: Travel can disrupt sleep and reduce perceived recovery in athletes. While the impact of travel on physical performance has been studied, its effect on cognitive performance remains unexplored.

Purpose: This study investigated the consequences of overnight long-haul travel on physical (part I) and cognitive performance (part II) in professional rugby players traveling overseas for competition.

Methods: In part I (n = 24), vertical-jump performance was assessed across 5 mornings surrounding travel (HOME, TRAVEL, and AWAY 1, 2, and 3). In part II (n = 24), mental fatigue and psychomotor vigilance (defined as the ability to respond to stimuli effectively) were assessed across 3 days (HOME, TRAVEL, and AWAY 1). Sleep was monitored on all nights preceding performance assessment using activity monitoring.

Results: Compared with HOME, TRAVEL reduced sleep quantity (part I. -219 [112] min; part II, -334 [233] min; both P < .001) and elevated in-flight mental fatigue (part II, +12 [18]; P < .05). Psychomotor vigilance was impaired during TRAVEL (+8% [6%] in valid response latencies ≤500 milliseconds; P < .001), and reactive jump strength was reduced at AWAY 1 (-7% [10%] in drop jump; P < .001). While psychomotor vigilance was restored by AWAY 1 (after hotel sleep), reactive jump strength remained diminished until AWAY 3 (-12% [9%] in drop jump compared with HOME; P < .001) after travel.

Conclusion: For teams traveling on long-haul journeys overnight for competition, it is recommended to arrive more than 3 days before matches to enable sufficient physical and cognitive recovery at the new destination to optimize performance away from home.

Purpose: To examine the association between reactive strength index (RSI) and metabolic cost of running (MCr) in master athletes. We hypothesized that individuals with a higher RSI would exhibit a lower MCr, that both variables would be associated, and that age would moderate this relationship.

Methods: Forty-five male master athletes participated to this study. A median split was performed to constitute 2 age groups (group 1, 47.7 [1.7] y old; group 2, 56.3 [4.6] y old). Participants underwent a single 45-minute session during which RSI was assessed with drop jumps, and MCr, during a continuous exercise of submaximal intensity performed on a treadmill.

Results: A small negative association was found between net MCr and RSI in the overall sample (RSI mean r = -.38, P < .05; RSI max r = -.38, P < .05). Group 1 exhibited a lower net MCr (P < .01, d = -0.84) and higher RSI (P < .01, d > 0.82) than group 2. However, the association between the 2 measures was verified specifically in group 2 (RSI from a 20-cm drop jump, r = -.53, P < .01; RSI mean, r = -.50, P < .05; RSI maximum, r = -.57, P < .01).

Conclusions: RSI is associated with net MCR in master athletes, particularly in older participants. Additional intervention studies are now required to further explore this association.