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Sweat Characteristics and Fluid Balance Responses During Two Heat Training Camps in Elite Female Field Hockey Players

Paul S.R. Goods, Bradley Wall, Brook Galna, Alannah K.A. McKay, Denise Jennings, Peter Peeling, and Greig Watson

We examined the sweat characteristics and fluid balance of elite female field hockey players during two heat training camps. Fourteen elite female field hockey players from the Australian national squad participated in two heat training camps held ∼6 months apart, following winter- (Camp 1) and summer-based training (Camp 2). Daily waking body mass (BM) and urine specific gravity (USG) were collected, along with several markers of sweat and fluid balance across two matches per camp. There was a 19% mean reduction in estimated whole-body sweat sodium concentration from Camp 1 (45.8 ± 6.5 mmol/L) to Camp 2 (37.0 ± 5.0 mmol/L; p < .001). Waking urine specific gravity ≥ 1.020 was observed in 31% of samples, with no significant differences in mean urine specific gravity or BM between camps (p > .05), but with substantial interindividual variation. Intramatch sweat rates were high (1.2–1.8 L/hr), with greater BM losses in Camp 1 (p = .030), resulting in fewer players losing ≥2% BM in Camp 2 (0%–8%), as compared with Camp 1 (36%–43%; p = .017). Our field data suggest that elite female field hockey players experience substantial sweat losses during competition in the heat regardless of the season. In agreement with previous findings, we observed substantial interindividual variation in sweat and hydration indices, supporting the use of individualized athlete hydration strategies.

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Training Regimen of an Elite Ultramarathon Runner: A Case Study of What Led Up to the 24-Hour World-Record Run

Jonathan Byrne, Sarah Lynch, and G. Monique Mokha

Purpose: Ultramarathon running has gained popularity over several decades. Although there has been considerable research on training for other running events, from the 100-m to the marathon at 26.2 miles (42.2 km), there is little evidence on best practices for ultramarathons, where distances potentially exceed 100 miles (160.9 km). Methods: In this case study, we examine the training regimen of an elite ultramarathon runner who broke 8 world records in 2021 and 2022, including the 24-hour run in which he ran 319.6 km in September 2022. Training data from December 28, 2020, to September 17, 2022, were collected from the Strava application database (recorded on Coros watch) and analyzed using Microsoft Excel and Tableau. Results: Our subject completed 5 training blocks, with volume per training block averaging 172.1 to 263 km/wk. Peak running volume per training block occurred on average 3.2 weeks out from races and reached a maximum of 378 km/wk. Recovery was emphasized the week following a race, with less running (19 km/wk) and more cross-training. Interval-type workouts (1- to 10-km repeats) were completed throughout training blocks. The average pace during the 24-hour world-record run was 4 minutes and 30 seconds per kilometer (4:30/km), closely matching the overall average training pace. Conclusions: These findings suggest that training for ultramarathon races should include high-volume running at varied paces and intensity with cross-training to avoid injuries. We hope that this evidence helps athletes understand how to prepare for these ultraendurance events.

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Auditing the Representation of Females Versus Males in Heat Adaptation Research

Monica K. Kelly, Ella S. Smith, Harry A. Brown, William T. Jardine, Lilia Convit, Steven J. Bowe, Dominique Condo, Joshua H. Guy, Louise M. Burke, Julien D. Périard, Rhiannon M.J. Snipe, Rodney J. Snow, and Amelia J. Carr

The aim of this audit was to quantify female representation in research on heat adaptation. Using a standardized audit tool, the PubMed database was searched for heat adaptation literature from inception to February 2023. Studies were included if they investigated heat adaptation among female and male adults (≥18–50 years) who were free from noncommunicable diseases, with heat adaptation the primary or secondary outcome of interest. The number and sex of participants, athletic caliber, menstrual status, research theme, journal impact factor, Altmetric score, Field-Weighted Citation Impact, and type of heat exposure were extracted. A total of 477 studies were identified in this audit, including 7,707 participants with ∼13% of these being female. Most studies investigated male-only cohorts (∼74%, n = 5,672 males), with ∼5% (n = 360 females) including female-only cohorts. Of the 126 studies that included females, only 10% provided some evidence of appropriate methodological control to account for ovarian hormone status, with no study meeting best-practice recommendations. Of the included female participants, 40% were able to be classified to an athletic caliber, with 67% of these being allocated to Tier 2 (i.e., trained/developmental) or below. Exercise heat acclimation was the dominant method of heat exposure (437 interventions), with 21 studies investigating sex differences in exercise heat acclimation interventions. We recommend that future research on heat adaptation in female participants use methodological approaches that consider the potential impact of sexual dimorphism on study outcomes to provide evidence-based guidelines for female athletes preparing for exercise or competition in hot conditions.

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The Dose–Response in Elite Soccer: Preliminary Insights From Menstrual-Cycle Tracking During the FIFA Women’s World Cup 2019

Dawn Scott, Georgie Bruinvels, Dean Norris, and Ric Lovell

Purpose: This preliminary study examined the influence of estimated menstrual-cycle (MC) phase on responses to soccer matches and training sessions in preparation for and during the FIFA (Fédération internationale de football association) Women’s World Cup 2019. Methods: Twenty outfield players representing a national team were tracked over a 45-day period. External (10-Hz global positioning system; total and distance covered at high-metabolic power [≥20 W·kg−1]) and internal load measures (minutes ≥80% heart-rate maximum, sessional ratings of perceived exertion) were collected during all training and matches, with single-item wellness measures (fatigue, soreness, sleep quality, and sleep duration) collected each morning prior to activity. MC phase was estimated individually via an algorithm, informed from pretournament survey responses and ongoing symptom reporting (FitrWoman). Model comparison statistics were used to determine the impact of estimated MC phase in nonhormonal contraceptive users (n = 16). Results: Sessional rating of perceived exertion responses to total distances ≥5 km were higher during the luteal phase (+0.6–1.0 au; P ≤ .0178) versus menstruation (phase 1), but no other observable dose–response trends were observed. Sleep, fatigue, and soreness ratings were not typically associated with MC phase, with the exception of exacerbated fatigue ratings in luteal versus follicular phase 48 hours postmatch (−0.73 au, P = .0275). Conclusions: Preliminary findings suggest that estimated MC phase may contribute to the understanding of the dose–response to soccer training and matches.

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Perceptions of Collaboration Between General and Special Educators in Physical Education

Christopher Mihajlovic

This article describes the perceptions and experiences of collaboration between teachers of physical education (n = 3) and special educators (n = 3) on teaching pupils with disabilities. Using a qualitative approach, the study seeks to establish the nature and extent of collaboration among these teachers and to identify the benefits and barriers to implementation. Semistructured interviews were used as the main data source. Data were collected from teachers working in the public school system in the southern part of Finland. The findings indicate that while teachers are mostly aware of the value of collaboration, its implementation varies immensely among the different schools. While the special educators in this study see themselves mainly responsible for supporting pupils with disabilities, the physical education teachers showed a strong commitment to the subject matter of their teaching. Participants also reported several challenges relating to time constraints, a lack of classroom support, and a shared vision of inclusive teaching.

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Variability of External Load Measures During Soccer Match Play: Influence of Player Fitness or Pacing?

Alireza Rabbani, Giorgios Ermidis, Filipe Manuel Clemente, and Craig Twist

Purpose: The aims of this study were to examine the variability of selected external load metrics within 15-minute intervals during soccer match play and examine their relationship with players’ high-intensity intermittent fitness. Methods: A total of 18 male soccer players were monitored for their external load metrics during 26 matches, which included total distance, high-metabolic-load distance, and mechanical work (defined as the sum of accelerations and decelerations >3 m2). Additionally, players completed the 30-15 Intermittent Fitness Test. Results: Total distance had lower coefficients of variation than high-metabolic-load distance and mechanical work (effect size [ES]: 5.2 to 6.4; very large). Within-player Δ-15min showed moderate to large decreases (ES: −0.7 to −1.6) and increases (ES: 0.9 to 1.8) in absolute and coefficient-of-variation values, respectively. Large relationships (r = .55 to .61) were observed between the Intermittent Fitness Test and 15-minmean and 15-minbest in all selected external load metrics. However, small to moderate (0.27 to 0.41) associations were observed between the Intermittent Fitness Test and Δ-15min in selected external load metrics. Conclusions: These findings suggest that players with relatively lower intermittent running capacity might show lower variability during matches, as evidenced by smaller reductions in high-intensity actions during the final 15 minutes. We attribute these observations to players’ possessing better pacing strategies.

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Effect of the Fran CrossFit Workout on Oxygen Uptake Kinetics, Energetics, and Postexercise Muscle Function in Trained CrossFitters

Manoel Rios, Klaus Magno Becker, Ana Sofia Monteiro, Pedro Fonseca, David B. Pyne, Victor Machado Reis, Daniel Moreira-Gonçalves, and Ricardo J. Fernandes

Purpose: Fran is one of the most popular CrossFit benchmark workouts used to control CrossFitters’ improvements. Detailed physiological characterization of Fran is needed for a more specific evaluation of CrossFitters’ training performance improvements. The aim of the study was to analyze the oxygen uptake ( V ˙ O 2 ) kinetics and characterize the energy system contributions and the degree of postexercise fatigue of the unbroken Fran. Methods: Twenty trained CrossFitters performed Fran at maximal exertion. V ˙ O 2 and heart-rate kinetics were assessed at baseline and during and post-Fran. Blood lactate and glucose concentrations and muscular fatigue were measured at baseline and in the recovery period. Results: A marked increase in V ˙ O 2 kinetics was observed at the beginning of Fran, remaining elevated until the end ( V ˙ O 2 peak : 49.2 [3.7] mL·kg−1·min−1, V ˙ O 2 amplitude: 35.8 [5.2] mL·kg−1·min−1, time delay: 4.7 [2.5] s and time constant: 23.7 [11.1] s; mean [SD]). Aerobic, anaerobic lactic, and alactic pathways accounted for 62% (4%), 26% (4%), and 12% (2%) of energy contribution. Reduction in muscle function in jumping ability (jump height: 8% [6%], peak force: 6% [4%], and maximum velocity: 4% [2%]) and plank prone test (46% [20%]) was observed in the recovery period. Conclusions: The Fran unbroken workout is a high-intensity effort associated with an elevated metabolic response. This pattern of energy response highlights the primary contribution of aerobic energy metabolism, even during short and very intense CrossFit workouts, and that recovery can take >24 hours due to cumulative fatigue.

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Effect of Wetsuit Use on Body Temperature and Swimming Performance During Training in the Pool: Recommendations for Open-Water Swimming Training With Wetsuits

Tomomi Fujimoto, Yuiko Matsuura, Yasuhiro Baba, and Reira Hara

Purpose: Open-water swimmers need to train with wetsuits to get familiar with them; however, body core temperature (T core) kinetics when using wetsuits in swimming-pool training remains unclear. The present study assessed the effects of wetsuit use in pool training on T core, subjective perceptions, and swimming performance to obtain suggestions for wearing wetsuits in training situations. Methods: Four elite/international-level Japanese swimmers (2 female, age 24 [1] y) completed two 10-km trials with (WS) and without wetsuit (SS) in the swimming pool (T w: 29.0 °C). During the trial, swimmers were allowed to remove their wetsuit if they could no longer tolerate the heat. T core was continuously recorded via ingestible temperature sensors. Swimming speed was estimated from every 100-m lap time. Results: T core increased by distance in both trials in all swimmers. T core when swimmers removed their wetsuit in the WS (distance: 3800 [245] m, time: 2744 [247] s) was higher than that at the same distance in the SS in all swimmers. Rating of perceived exertion was higher in the SS than the WS, and swimming speed was slower in the WS than the SS in all swimmers. Conclusion: Wetsuit use during pool training increases T core and decreases swimming performance. Although wearing wetsuits in training situations is important for familiarization, for the safety of the swimmers, it is recommended that they remove their wetsuit if they feel too hot.

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Acute Responses to Repeated-Sprint Training in Hypoxia Combined With Whole-Body Cryotherapy: A Preliminary Study

Thibaud Mihailovic, Alain Groslambert, Romain Bouzigon, Simon Feaud, Grégoire P. Millet, and Philippe Gimenez

Purpose: This study aimed to investigate acute psychophysiological responses to repeated-sprint training in hypoxia (RSH) combined with whole-body cryotherapy (WBC). Method: Sixteen trained cyclists performed 3 sessions in randomized order: RSH, WBC-RSH (WBC pre-RSH), and RSH-WBC (WBC post-RSH). RSH consisted of 3 sets of 5 × 10-second sprints with 20-second recovery at a simulated altitude of 3000 m. Power output, muscle oxygenation (tissue saturation index), heart-rate variability, and recovery perception were analyzed. Sleep quality was assessed on the nights following test sessions and compared with a control night using nocturnal ActiGraphy and heart-rate variability. Results: Power output did not differ between the conditions (P = .27), while the decrease in tissue saturation index was reduced for WBC-RSH compared to RSH-WBC in the last set. In both conditions with WBC, the recovery perception was higher compared to RSH (WBC-RSH: +15.4%, and RSH-WBC: +21.9%, P < .05). The number of movements during the RSH-WBC night was significantly lower than for the control night (−18.7%, P < .01) and WBC-RSH (−14.9%, P < .05). RSH led to a higher root mean square of the successive differences of R-R intervals and high-frequency band during the first hour of sleep compared to the control night (P < .05) and RSH-WBC (P < .01). Conclusions: Inclusion of WBC in an RSH session did not modify the power output but could improve prolonged performance in hypoxia by maintaining muscle oxygenation. A single RSH session did not deteriorate sleep quality. WBC, particularly when performed after RSH, positively influenced recovery perception and sleep.

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Quantifying Offense and Defense Workloads in Professional Rugby Union

Luke J. Stevens, Will G. Hopkins, Jessica A. Chittenden, Bianca Z. Koper, and Tiaki Brett Smith

Purpose: Rugby union is a contact team sport demanding high levels of physical capacity, and understanding the match workloads can be useful to inform training. In this study, the factors influencing locomotion and contact workloads for offensive and defensive ball-in-play periods are quantified. Methods: Locomotion and contact metrics were collected from global positioning system units and videos for 31 professional players of a Super Rugby team across 14 games in the 2021 season. Data were analyzed with a generalized mixed-model procedure that included effects for type of play, playing position, match outcome, and ball-in-play time. Magnitudes were assessed with standardization, and evidence for substantial magnitudes was derived from sampling uncertainty. Results: When offense was compared to defense, most metrics showed decisively substantial increases (small to moderate) for forwards and backs. There was decisive evidence that locomotion metrics were substantially lower (large differences) and contact metrics were higher (very large differences) when comparing forwards to backs on offense and defense. When winning was compared to losing, there was good evidence that forwards experienced small increases in overall workload on defense, and backs experienced a small increase in high-speed running and a moderate decrease in contacts on offense. Match-to-match changes associated with ball-in-play time, attributed to fatigue, were decisive (moderate to very large) across most metrics for forwards and backs in offense and defense. Conclusions: The increased locomotion and contact workloads in offensive periods and the differing physical requirements between positions and match outcomes for both types of play are novel findings that should aid practitioners in designing effective training.