Purpose: This study aimed to characterize core-temperature (Tc) responses of swimmers competing at the 2024 3-km World Aquatics Masters Open Water Swimming Championships. Methods: Within a cross-sectional observational study design, swimmers (n = 48 [23 male, 25 female]) ingested a telemetric Tc pill 4 hours before their race. Water temperatures were 20.9 °C (male; mean wet-bulb-globe temperature 25.9 °C) and 20.5 °C (female; mean wet-bulb-globe temperature: 25.4 °C). Linear mixed models determined differences between males and females for race-start, mean in-race, and peak Tc. Random coefficient models determined relationships between (1) sex, race time, body mass index (BMI), body-mass change or age, and Tc peak; (2) sex, race time, BMI, body-mass change or age, and Tc nadir; (3) sex, Tc peak, BMI, body-mass change or age, and race time, and (4) sex, Tc peak, BMI, body-mass change, or age and race ranking. Results: The mean in-race Tc was 37.8 °C (36.1–38.8 °C); however, there were highly variable individual Tc responses (−3.1 to +2.7 °C). One swimmer experienced mild hypothermia (Tc ≤ 35.0 °C), and 5 exceeded 39.0 °C, a risk factor for heat-related illness. There were no statistical differences between males and females for race-start, mean, and peak Tc (P ≥ .243). Higher peak Tc was associated with faster race time (P = .05), higher race rank (P = .027), and higher BMI (P = .001). Conclusions: Highly variable Tc responses (−3.1 to +2.7 °C) were observed, demonstrating that organizers of mass-participation open-water swimming events should always be prepared for, and provide facilities to treat, swimmers experiencing cold-/heat-related health incidents during competition.
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Core-Temperature Responses at the 3-km World Aquatics Open-Water Swimming Masters Championships in Doha 2024
Chris J. Esh, Valentin Dablainville, Feriel Dalansi, Sayyam Kathuria, and Marco Cardinale
Flight-Time Method Modified: Development of a Novel and More Accurate Method for Measuring Vertical Jump Height Using a Smartphone Application
Takuya Nishioka, Shota Yamaguchi, and Takayuki Inami
Purpose: The flight-time method (FT) is used for measuring vertical jump height (JH) in the field because of its convenience; however, FT overestimates JH when the lower limb is flexed at landing. Herein, we proposed a new method (ie, flight-time method modified [FTM]) to address the problem of FT and evaluate its validity and reliability. Methods: A total of 24 men performed 6 countermovement jumps on force plates (sampling rate: 1000 Hz) while being recorded with a smartphone high-speed camera at 240 frames·s–1. JH was calculated by the impulse–momentum method (IM), FT, and FTM. For FTM, the flight time and JH were calculated based on the displacement of the greater-trochanter marker using a smartphone application. Results: JH calculated using FT was significantly higher (P < .001) compared with JH calculated by IM; however, JH calculated by FTM showed no significant difference with JH calculated by IM. Furthermore, JH calculated by FTM, compared with JH calculated by FT (ρ = .882; 95% CI, .838–.914), exhibited a stronger, nearly perfect, and significantly positive correlation (ρ = .987; 95% CI, .982–.991) with JH calculated by IM and showed high reliability. Conclusions: The FTM proposed in this study had higher concurrent validity compared with FT and a high reliability for measuring countermovement JH because it was not affected by lower-extremity flexion at landing. Therefore, practitioners should consider using FTM as a convenient, low-cost, reliable, and more valid method for measuring JH in the field.
Volume 19 (2024): Issue 11 (Nov 2024)
Effects of Training Volume in the Bench-Press Exercise Performed With Interrepetition Rest Periods on Strength Gains and Neuromuscular Adaptations
José A. Páez-Maldonado, Claro Cano, Pedro J. Cornejo-Daza, Juan Sánchez-Valdepeñas, Luis Rodiles-Guerrero, Mathias Wernbom, Manuel Ortega-Becerra, and Fernando Pareja-Blanco
Purpose: To investigate the effects of 3 training volumes in the bench-press exercise performed with interrepetition rest periods, matched for fatigue, on strength gains and neuromuscular adaptations. Methods: Forty-three resistance-trained men were randomized into 3 groups: low (LOW), moderate (MOD), and high (HIG) volume. The intensities increased from 70% to 85% of 1-repetition maximum (1RM) over the 8-week training period. Each session consisted of only 1 set with short interrepetition rest periods. LOW performed only 3 repetitions per session (8-wk total: 48 repetitions); MOD completed 15, 12, 10, and 8 repetitions per session with 70%, 75%, 80%, and 85% 1RM, respectively (8-wk total: 180); and HIG performed 24, 21, 18, and 15 repetitions per session with 70%, 75%, 80%, and 85% 1RM, respectively (8-wk total: 312). Progressive loading and fatigue tests were conducted in the bench-press exercise before and after the training period. Electromyography (EMG) signals from the triceps brachii were registered during these tests. Results: HIG and MOD showed higher velocity loss than LOW (16% vs 12%). No significant group × time interaction was observed for any variable. All groups improved significantly in all strength-related variables, except for maximal unloaded velocity, where only MOD obtained significant gains. Only LOW and MOD induced significant improvements in EMG. MOD obtained the greatest effect sizes in almost all strength variables. Conclusions: No significant differences were found in the performance gains obtained by each group despite the wide differences in the total volume accumulated by each group.
Factors Informing Training Load During the Transition From Club to National Football Teams
Joshua J Gould, Ewan Clements, Fabian Ehrmann, and Rob Duffield
Purpose: This study examined the relationship of precamp match exposure, travel demands, perceptual wellness, and musculoskeletal screening with ensuing training load (TL) during national-team (NT) duties for international footballers (soccer). Methods: Match minutes and days since last match prior to NT arrival were collected for match exposure. Travel duration and time-zone difference were included as travel demands. Perceptual fatigue, soreness, sleep quality, and stress scores were collected via self-report questionnaire on arrival to NT. Musculoskeletal testing on day 1 of NT included knee to wall and hip internal and external rotation. Relative TL across the first 3 days of NT camp was measured via total distance, high-speed running distance, very high-speed running distance, and accelerations and decelerations per minute. Linear mixed models determined the influence of independent variables on respective TL metrics, with the player included as a random effect. Results: Total distance, high-speed running, very high-speed running, and decelerations per minute were all highest on day 3 (P < .001). Small relationships existed (R 2 < .15) between decreased total distance per minute and increased soreness (P = .037), while decreased high-speed running per minute was associated with increased fatigue (P = .017). Small associations existed between decreased accelerations per minute, increased hip internal rotation (P < .001), fatigue (P = .033), and knee to wall (P = .016), while decreased decelerations per minute were associated with increased soreness (P = .001), knee to wall (P = .024), and days between recent match and arrival (P = .003). Conclusions: Very small relationships existed between fatigue, soreness, musculoskeletal screening, and prior match exposure with TL. The larger influence of camp day suggests that deliberate periodization of training is a major factor for prescription on arrival into NT duties.
Greater Relative First and Second Lactate Thresholds in Females Compared With Males: Consideration for Exercise Prescription
José Antonio Benítez-Muñoz, Miguel Ángel Rojo-Tirado, Pedro José Benito Peinado, Juan M. Murias, Domingo González-Lamuño, and Rocío Cupeiro
Purpose: To investigate differences between females and males at lactate thresholds 1 (LT1) and 2 (LT2). Methods: Twenty-four female and twenty male participants performed an incremental cycle-ergometer test until exhaustion, where LT1 and LT2 were determined in each volunteer. Results: Power output at LT1 and LT2 was lower in females than in males (P < .001). In addition, power output relative to peak power was higher in females at LT1 and LT2 (P < .001). However, heart rate was higher in females than males at LT1 and LT2 (P = .008). Furthermore, the heart rate relative to maximal heart rate was higher in females compared with males at LT1 and LT2 (P = .002). Conclusion: Females and males may be in a different metabolic situation at the same percentage of maximum. This study helps to reduce sex bias in science, and future guidelines should consider establishing exercise prescription recommendations according to sex. Clinical Trial: NCT06104150.
Neuromuscular Fatigue During Brazilian Jiujitsu Matches: Analysis of Upper and Lower Limbs
Athos da Silva Fagundes, Alisson Henrique Marinho, Iron Lopes Freitas, Brandel José Pacheco Lopes Filho, Cintia Rodacki, Romulo Bertuzzi, Adriano Eduardo Lima-Silva, and Gislaine Cristina-Souza
Purpose: To determine the effects of repeated Brazilian jiujitsu (BJJ) matches on neuromuscular fatigue in forearm-flexor and knee-extensor muscles. Methods: Twelve BJJ athletes (8 men and 4 women) performed a simulated BJJ tournament composed of four 8-minute matches interspersed by 16-minute intervals. Neuromuscular fatigue was assessed via prematch to postmatch(es) reductions in maximal voluntary isometric contraction (MVIC), voluntary activation, and potentiated twitch force (Ptwpot) in the forearm-flexor and knee-extensor muscles. Results: The MVIC of the knee extensors and forearm flexors reduced from prematch 1 to postmatch 2 and remained suppressed until postmatch 4 (P < .034). The voluntary activation of the knee extensors declined only after match 4, whereas the voluntary activation of the forearm flexors did not change throughout the matches (P = .102). Ptwpot of knee extensors decreased from prematch 1 to postmatch 1 (P < .001) and remained reduced until postmatch 4 (P < .001). Ptwpot of the forearm flexors reduced after every match (P < .010), with complete recovery occurring only before the second match (P = .99). The magnitude of the prematch-to-postmatch reduction in Ptwpot was lower in knee extensors than in forearm flexors (P = .044). Conclusions: Repeated BJJ matches induced neuromuscular fatigue, mainly due to impairments in muscle contractile function (ie, peripheral fatigue). The time between BJJ matches seems to be insufficient to allow complete recovery of neuromuscular function, which may influence performance during subsequent matches.
Influence of Menstrual-Cycle Phase on Sleep and Recovery Following High- and Low-Intensity Training in Eumenorrheic Endurance-Trained Women: The Female Endurance Athlete Project
Madison Y. Taylor, Maria Hrozanova, Liv Nordengen, Øyvind Sandbakk, John O. Osborne, and Dionne A. Noordhof
Purpose: To investigate the influence of menstrual-cycle (MC) phase on objective sleep and perceived recovery following high- (HIT) and low-intensity training (LIT) in endurance-trained women. Methods: Fifteen naturally menstruating, endurance-trained women completed standardized HIT and LIT sessions during the early follicular phase (EFP), ovulatory phase (OP), and midluteal phase (MLP) of 2 MCs. Overnight sleep was monitored using a Somnofy sleep monitor after each training session, and perceived recovery was assessed after 24 hours using self-report scales. MC phases were determined using the 3-step method, and noneumenorrheic MCs were retrospectively excluded from analysis. Results: MC phase had a main effect on wake after sleep onset (P ≤ .001), with higher values in MLP (33 [22] min) than EFP (22 [19] min, P = .043) and OP (14 [9] min, P = .001), sleep efficiency (P = .033), with lower values in MLP (87% [6%]) than OP (90% [8%], P = .047), and light sleep (P = .023) with higher values in MLP (59% [6%]) than EFP (54% [7%], P = .037). Session type had a main effect on perceived recovery (P < .018) and perceived muscle soreness (P = .007), indicating lower perceived recovery and higher perceived muscle soreness following HIT compared to LIT (P < .001, P = .018, respectively). No interactions were found between MC phase and session type for any of the measured variables. Conclusions: Objective sleep quality, but not perceived recovery, was influenced by MC phase, as indicated by small impairments to multiple indices of objective sleep during MLP. There were no interactions between MC phase and session type, indicating that the effect of MC on sleep and recovery is consistent regardless of session type.
Impact of Generalized Versus Individualized Load–Velocity Equations on Velocity-Loss Magnitude in Bench-Press Exercise: Mixed-Model and Equivalence Analysis
Miguel Sánchez-Moreno, Beatriz Bachero-Mena, Juan Sánchez-Valdepeñas, Fabio Yuzo Nakamura, and Fernando Pareja-Blanco
Purpose: This study analyzed the influence of 2 velocity-based training-load prescription strategies (general vs individual load–velocity equations) on the relationship between the magnitude of velocity loss (VL) and the percentage of repetitions completed in the bench-press exercise. Methods: Thirty-five subjects completed 6 sessions consisting of performing the maximum number of repetitions to failure against their 40%, 60%, and 80% of 1-repetition maximum (1RM) in the Smith machine bench-press exercise using generalized and individualized equations to adjust the training load. Results: A close relationship and acceptable error were observed between percentage of repetitions completed and the percentage of VL reached for the 3 loading magnitudes and the 2 load-prescription strategies studied (R 2 from .83 to .94; standard error of the estimate from 7% to 10%). A simple main effect was observed for load and VL thresholds but not for load-prescription strategies. No significant interaction effects were revealed. The 40% and 60% 1RM showed equivalence on data sets and the most regular variation, whereas the 80% 1-repetition maximum load showed no equivalence and more irregular variation. Conclusion: These results suggest that VL is a useful variable to predict percentage of repetitions completed in the bench-press exercise, regardless of the strategy selected to adjust the relative load. However, caution should be taken when using heavy loads.
Warm-Up in Triathlon: Do Triathletes Follow the Scientific Guidelines?
Claudio Quagliarotti, Simone Villanova, Alessio Marciano, Óscar López-Belmonte, Cristiano Caporali, Alessandro Bottoni, Romuald Lepers, and Maria Francesca Piacentini
Purpose: Warming up before competition is universally recognized as an effective way to enhance performance. However, only a few articles have directly investigated different warm-up strategies adopted by triathletes and suggested by coaches. The Olympic-distance triathlon is an endurance competition characterized, at least for the elite, by a fast start with a strong correlation to the final position in the race. Thus, executing a proper warm-up protocol would be beneficial in optimizing performance. The present study aimed to provide an overview of the warm-up protocol adopted/suggested by national-caliber triathletes/coaches before an Olympic-distance triathlon race. Methods: Online surveys were created and shared between national- and international-caliber Italian, French, and Spanish triathletes and coaches. Information about the rationale, structure, and specific exercises adopted/suggested during personal warm-up protocols was collected. Thereafter, triathletes were grouped according to the discipline sequence reported. Results: Seventy-nine triathletes and nineteen coaches completed the survey. The cycle–run–swim was the most reported discipline sequence adopted, with a total time of 90.0 (25.0) minutes, against the 62.5 (25.0) minutes suggested by coaches. Conditioning exercises were performed by only 31.6% of triathletes 20 to 10 minutes before the race start. Conclusions: Triathletes who took part in this survey adopted very long protocols with the specific intention of including all disciplines. These results highlight the need to raise awareness in triathletes and coaches on the correct warm-up procedures and to stimulate researchers to design studies that directly investigate the effects of different warm-up protocols before competitions.