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Cowe S, Cooper S, Malcolm R, Hall L, Donkin D, Sunderland C. The effect of a combined cooling intervention on cognitive function in the heat during an intermittent running protocol. Eur J Sport Sci 2024. [PMID: 39117584 DOI: 10.1002/ejsc.12178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 06/06/2024] [Accepted: 07/24/2024] [Indexed: 08/10/2024]
Abstract
Despite optimal cognitive function being essential for performance, there is a lack of research on the effectiveness of combined cooling interventions on team sport athlete's cognitive function when exercising in the heat. In a randomised, crossover design, 12 unacclimatised men (age: 22.3 ± 3.0 years, body mass: 73.4 ± 5.1 kg, height: 181.0 ± 5.3 cm andV ˙ O 2 $\dot{\mathrm{V}}{\mathrm{O}}_{2}$ max: 51.2 ± 9.5 mL/kg/min) participated in a control (CON) and combined cooling trial (ice slurry and ice collar; COOL). A battery of cognitive tests were completed prior to, during (at half-time) and following a 90-min intermittent running protocol in the heat (33°C, 50% relative humidity (RH)). Perceptual and physiological measures were taken throughout the protocol. In CON, response times were quicker on the Stroop task complex level (p = 0.002) and the visual search test complex level at full-time (p = 0.014) compared to COOL. During COOL, response times were quicker at half-time on the Stroop task complex level (p = 0.024) compared to CON. Lower rectal temperatures were seen during COOL (CON: 37.44 ± 0.65°C and COOL: 37.28 ± 0.68°C) as well as lower skin, neck and forehead temperatures (main effect of trial, all p < 0.05). Lower ratings of thermal sensation and perceived exertion and enhanced thermal comfort were recorded during COOL (main effect of trial, all p < 0.05). Whilst minimal differences in cognitive function were found when using the combined cooling intervention, the findings highlight a practical and effective strategy to improving many physiological and perceptual responses to intermittent exercise in the heat.
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Affiliation(s)
- Stacey Cowe
- Department of Sport Science, Sport, Health and Performance Enhancement (SHAPE) Research Centre, Nottingham Trent University, Nottingham, UK
| | - Simon Cooper
- Department of Sport Science, Sport, Health and Performance Enhancement (SHAPE) Research Centre, Nottingham Trent University, Nottingham, UK
| | - Rachel Malcolm
- Department of Sport Science, Sport, Health and Performance Enhancement (SHAPE) Research Centre, Nottingham Trent University, Nottingham, UK
| | - Louis Hall
- Department of Sport Science, Sport, Health and Performance Enhancement (SHAPE) Research Centre, Nottingham Trent University, Nottingham, UK
| | - David Donkin
- Department of Sport Science, Sport, Health and Performance Enhancement (SHAPE) Research Centre, Nottingham Trent University, Nottingham, UK
| | - Caroline Sunderland
- Department of Sport Science, Sport, Health and Performance Enhancement (SHAPE) Research Centre, Nottingham Trent University, Nottingham, UK
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2
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Fenemor SP, Gill ND, Driller MW, Mills B, Sella F, Beaven CM. Small Performance Effects of a Practical Mixed-Methods Cooling Strategy in Elite Team Sport Athletes. RESEARCH QUARTERLY FOR EXERCISE AND SPORT 2023; 94:1162-1168. [PMID: 36167423 DOI: 10.1080/02701367.2022.2125158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 09/02/2022] [Indexed: 06/16/2023]
Abstract
Purpose: The ingestion of ice slurry and application of ice towels can elicit favorable physiological, perceptual, and performance benefits when used individually; however, the combined use and effectiveness of these practical cooling strategies have not been assessed using a sport-specific performance test, based on actual match demands, in an elite team sport context. Methods: Ten non-heat acclimated elite male rugby sevens athletes undertook two cycling heat response tests (HRT) designed to be specific to the demands of rugby sevens in hot conditions (35°C, 80% rH). In a crossover design, the HRTs were conducted with (COOLING) and without (HOT) the combined use of internal (ice slushy ingestion) and external (application of ice towels to the head, neck, and face) pre- and per-cooling strategies. Physiological, perceptual, and performance variables were monitored throughout each HRT. Results: COOLING resulted in reductions in mean tympanic temperature (-0.4 ± 0.2°C; d = 1.18); mean heart rate (-5 ± 8 bpm; d = 0.53); thermal discomfort (-0.5 ± 0.9 AU; d = 0.48); and thirst sensation (-1.0 ± 1.1 AU; d = 0.61) during the HRT. COOLING also resulted in a small increase in 4-min time trial power output (by 7 ± 33 W, ~3%; d = 0.35) compared to HOT. Discussion: A combination of internal and external pre- and per-cooling strategies can result in a range of small physiological, perceptual, and performance benefits during a rugby sevens specific HRT, compared to undertaking no cooling. Practitioners should include such strategies when performing in hot conditions.
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Affiliation(s)
- S P Fenemor
- University of Waikato Adams Centre for High Performance
- High Performance Sport New Zealand
| | - N D Gill
- University of Waikato Adams Centre for High Performance
- New Zealand Rugby Union
| | | | | | - F Sella
- University of Waikato Adams Centre for High Performance
| | - C M Beaven
- University of Waikato Adams Centre for High Performance
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3
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Iwahashi M, Chaen Y, Yanaoka T, Kurokawa Y, Hasegawa H. Cold water immersion of the hand and forearm during half-time improves intermittent exercise performance in the heat. Front Physiol 2023; 14:1143447. [PMID: 37362443 PMCID: PMC10285063 DOI: 10.3389/fphys.2023.1143447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 05/26/2023] [Indexed: 06/28/2023] Open
Abstract
The present study aimed to investigate the effect of cold water immersion of the hand and forearm during half-time (HT) on intermittent exercise performance and thermoregulation by imitating intermittent athletic games in the heat. In a randomized crossover design, 11 physically active men performed the first half (first and second block) and second half (third and fourth block) intermittent cycling exercise protocol, which consisted of a 5-s maximal power pedalling (body weight × 0.075 kp) every minute separated by 25-s of unloaded pedalling and rest (30 s) in the heat (33°C, 50% relative humidity). The two-halves were separated by a 15-min HT. During HT, the participants were assigned to the CON (sedentary resting) or COOL (immersion of hands and forearms in cold water at 15-17°C) condition. The mean power output in the second half was significantly greater (third and fourth block: p < 0.05) in the COOL than in the CON condition. Moreover, there was a significant decrease in the rectal (0.54 ± 0.17°C, p < 0.001) and mean skin (1.86 ± 0.34°C, p < 0.05) temperatures of the COOL condition during HT. Furthermore, the heart rate (16 ± 7 bpm, p < 0.05) and skin blood flow (40.2 ± 10.5%, p < 0.001) decreased at the end of HT in the COOL condition. In the second half, thermal sensation was more comfortable in the COOL condition (p < 0.001). Cold water immersion of the hand and forearm during HT improved physiological and reduced perceived heat stress. Moreover, it prevented a reduction in intermittent exercise performance in the second half.
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4
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Heydenreich J, Koehler K, Braun H, Grosshauser M, Heseker H, Koenig D, Lampen A, Mosler S, Niess A, Schek A, Carlsohn A. Effects of internal cooling on physical performance, physiological and perceptional parameters when exercising in the heat: A systematic review with meta-analyses. Front Physiol 2023; 14:1125969. [PMID: 37113693 PMCID: PMC10126464 DOI: 10.3389/fphys.2023.1125969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 03/27/2023] [Indexed: 04/29/2023] Open
Abstract
Background: An elevated core temperature (Tcore) increases the risk of performance impairments and heat-related illness. Internal cooling (IC) has the potential to lower Tcore when exercising in the heat. The aim of the review was to systematically analyze the effects of IC on performance, physiological, and perceptional parameters. Methods: A systematic literature search was performed in the PubMed database on 17 December 2021. Intervention studies were included assessing the effects of IC on performance, physiological, or perceptional outcomes. Data extraction and quality assessment were conducted for the included literature. The standardized mean differences (SMD) and 95% Confidence Intervals (CI) were calculated using the inverse-variance method and a random-effects model. Results: 47 intervention studies involving 486 active subjects (13.7% female; mean age 20-42 years) were included in the meta-analysis. IC resulted in significant positive effects on time to exhaustion [SMD (95% CI) 0.40 (0.13; 0.67), p < 0.01]. IC significantly reduced Tcore [-0.19 (22120.34; -0.05), p < 0.05], sweat rate [-0.20 (-0.34; -0.06), p < 0.01], thermal sensation [-0.17 (-0.33; -0.01), p < 0.05], whereas no effects were found on skin temperature, blood lactate, and thermal comfort (p > 0.05). IC resulted in a borderline significant reduction in time trial performance [0.31 (-0.60; -0.02), p = 0.06], heart rate [-0.13 (-0.27; 0.01), p = 0.06], rate of perceived exertion [-0.16 (-0.31; -0.00), p = 0.05] and borderline increased mean power output [0.22 (0.00; 0.44), p = 0.05]. Discussion: IC has the potential to affect endurance performance and selected physiological and perceptional parameters positively. However, its effectiveness depends on the method used and the time point of administration. Future research should confirm the laboratory-based results in the field setting and involve non-endurance activities and female athletes. Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42022336623.
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Affiliation(s)
- Juliane Heydenreich
- Working Group Sports Nutrition of German Nutrition Society, Bonn, Germany
- Institute of Sports Sciences, Johannes Gutenberg-University of Mainz, Mainz, Germany
- *Correspondence: Juliane Heydenreich,
| | - Karsten Koehler
- Working Group Sports Nutrition of German Nutrition Society, Bonn, Germany
- Department of Sport and Health Sciences, Technical University of Munich, Munich, Germany
| | - Hans Braun
- Working Group Sports Nutrition of German Nutrition Society, Bonn, Germany
- Manfred Donike Institute for Doping Analysis, Institute of Biochemistry, German Sport University Cologne, Cologne, Germany
| | - Mareike Grosshauser
- Working Group Sports Nutrition of German Nutrition Society, Bonn, Germany
- Olympic Center Rhineland-Palatinate/Saarland, Saarbrücken, Germany
| | - Helmut Heseker
- Working Group Sports Nutrition of German Nutrition Society, Bonn, Germany
- Institute of Nutrition, Consumption and Health, University of Paderborn, Paderborn, Germany
| | - Daniel Koenig
- Working Group Sports Nutrition of German Nutrition Society, Bonn, Germany
- Division of Sports Medicine, Exercise Physiology and Prevention, Center for Sport Science and University Sports, University of Vienna, Vienna, Austria
| | - Alfonso Lampen
- Working Group Sports Nutrition of German Nutrition Society, Bonn, Germany
- Risk Assessment Strategies, German Federal Institute for Risk Assessment, Berlin, Germany
| | - Stephanie Mosler
- Working Group Sports Nutrition of German Nutrition Society, Bonn, Germany
- Olympic Center Stuttgart, Stuttgart, Germany
| | - Andreas Niess
- Working Group Sports Nutrition of German Nutrition Society, Bonn, Germany
- Department of Sports Medicine, University Hospital Tübingen, Tübingen, Germany
| | - Alexandra Schek
- Working Group Sports Nutrition of German Nutrition Society, Bonn, Germany
- Editorial Team of the Journal Leistungssport, German Olympic Sports Confederation, Frankfurt, Germany
| | - Anja Carlsohn
- Working Group Sports Nutrition of German Nutrition Society, Bonn, Germany
- Department of Nutrition and Home Economics, University of Applied Science Hamburg, Hamburg, Germany
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Roriz M, Brito P, Teixeira FJ, Brito J, Teixeira VH. Performance effects of internal pre- and per-cooling across different exercise and environmental conditions: A systematic review. Front Nutr 2022; 9:959516. [PMID: 36337635 PMCID: PMC9632747 DOI: 10.3389/fnut.2022.959516] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 09/19/2022] [Indexed: 11/13/2022] Open
Abstract
Exercise in a hot and humid environment may endanger athlete's health and affect physical performance. This systematic review aimed to examine whether internal administration of ice, cold beverages or menthol solutions may be beneficial for physical performance when exercising in different environmental conditions and sports backgrounds. A systematic search was performed in PubMed, Web of Science, Scopus and SPORTDiscus databases, from inception to April 2022, to identify studies meeting the following inclusion criteria: healthy male and female physically active individuals or athletes (aged ≥18 years); an intervention consisting in the internal administration (i.e., ingestion or mouth rinse) of ice slush, ice slurry or crushed ice and/or cold beverages and/or menthol solutions before and/or during exercise; a randomized crossover design with a control or placebo condition; the report of at least one physical performance outcome; and to be written in English. Our search retrieved 2,714 articles in total; after selection, 43 studies were considered, including 472 participants, 408 men and 64 women, aged 18-42 years, with a VO2max ranging from 46.2 to 67.2 mL⋅kg-1⋅min-1. Average ambient temperature and relative humidity during the exercise tasks were 32.4 ± 3.5°C (ranging from 22°C to 38°C) and 50.8 ± 13.4% (varying from 20.0% to 80.0%), respectively. Across the 43 studies, 7 exclusively included a menthol solution mouth rinse, 30 exclusively involved ice slurry/ice slush/crushed ice/cold beverages intake, and 6 examined both the effect of thermal and non-thermal internal techniques in the same protocol. Rinsing a menthol solution (0.01%) improved physical performance during continuous endurance exercise in the heat. Conversely, the ingestion of ice or cold beverages did not seem to consistently increase performance, being more likely to improve performance in continuous endurance trials, especially when consumed during exercises. Co-administration of menthol with or within ice beverages seems to exert a synergistic effect by improving physical performance. Even in environmental conditions that are not extreme, internal cooling strategies may have an ergogenic effect. Further studies exploring both intermittent and outdoor exercise protocols, involving elite male and female athletes and performed under not extreme environmental conditions are warranted. Systematic review registration: [https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021268197], identifier [CRD42021268197].
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Affiliation(s)
- Maria Roriz
- Faculty of Nutrition and Food Sciences, University of Porto (FCNAUP), Porto, Portugal
- Futebol Clube do Porto, Porto, Portugal
| | - Pedro Brito
- Research Center in Sports Sciences, Health Sciences and Human Development, CIDESD, University of Maia, ISMAI, Maia, Portugal
| | - Filipe J. Teixeira
- Interdisciplinary Center for the Study of Human Performance (CIPER), Faculdade de Motricidade Humana, Universidade de Lisboa, Cruz-Quebrada, Portugal
- Atlântica, Instituto Universitário, Fábrica da Pólvora de Barcarena, Barcarena, Portugal
- Bettery Lifelab, Bettery S.A., Lisbon, Portugal
| | - João Brito
- Portugal Football School, Portuguese Football Federation, Oeiras, Portugal
| | - Vitor Hugo Teixeira
- Faculty of Nutrition and Food Sciences, University of Porto (FCNAUP), Porto, Portugal
- Futebol Clube do Porto, Porto, Portugal
- Research Centre in Physical Activity, Health and Leisure (CIAFEL), Faculty of Sports, University of Porto (FADEUP), Porto, Portugal
- Laboratory for Integrative and Translational Research in Population Health (ITR), Porto, Portugal
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6
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Naito T, Saito T, Morito A, Yamada S, Shimomasuda M, Nakamura M. Pre-cooling with ingesting a high-carbohydrate ice slurry on thermoregulatory responses and subcutaneous interstitial fluid glucose during heat exposure. J Physiol Anthropol 2022; 41:34. [PMID: 36217207 PMCID: PMC9549659 DOI: 10.1186/s40101-022-00309-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 09/28/2022] [Indexed: 11/07/2022] Open
Abstract
The purpose of this study was to compare the effects of ingesting ice slurries with two different carbohydrate contents on body temperatures and the subcutaneous interstitial fluid glucose level during heat exposure. Seven physically active men underwent one of three interventions: the ingestion of 7.5 g/kg of a control beverage (CON: 26°C), a normal-carbohydrate ice slurry (NCIS: −1°C), or a high-carbohydrate ice slurry (HCIS: −5°C). The participants were monitored for a 120-min period that included 10 min of rest, 25 min of exposure to the experimental cooling intervention (during which the beverage was ingested), and 85 min of seated rest in a climate chamber (36°C, 50% relative humidity). The rectal temperature in the HCIS and NCIS trials was lower than that in the CON trial from 40 to 75 min. The infrared tympanic temperature was also lower in the HCIS and NCIS trials than in the CON trial from 20 to 50 min, whereas the deep thigh or mean skin temperatures were not significantly different among the three groups. From 90 to 120 min, the subcutaneous interstitial fluid glucose level in the NCIS trial was lower than that at 65 min; however, reductions were not seen in the HCIS and CON trials. These findings suggest that both HCIS ingestion and conventional NCIS ingestion were effective cooling strategies for reducing thermal strain, while HCIS ingestion may also enable a higher subcutaneous interstitial fluid glucose level to be maintained, ensuring an adequate supply of required muscle substrates.
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Affiliation(s)
- Takashi Naito
- grid.419627.fDepartment of Sports Research, Japan Institute of Sports Sciences, 3-15-1 Nishigaoka Kita-ku, Tokyo, 115-0056 Japan ,grid.440874.b0000 0001 2183 8345Faculty of Law, Hokkai-Gakuen University, 4-1-40 Asahimachi Toyohira-ku, Sapporo City, Hokkaido 062-8605 Japan
| | - Tatsuya Saito
- grid.419627.fDepartment of Sports Research, Japan Institute of Sports Sciences, 3-15-1 Nishigaoka Kita-ku, Tokyo, 115-0056 Japan ,grid.265107.70000 0001 0663 5064Faculty of Medicine, Tottori University, 4-101 Koyamachominami, Tottori City, Tottori 683-8550 Japan
| | - Akihisa Morito
- grid.419836.10000 0001 2162 3360Health Science Research R&D Laboratories, Taisho Pharmaceutical Co., Ltd., 1-403 Yoshinomachi Kita-ku, Saitama City, Saitama 331-9530 Japan
| | - Satoshi Yamada
- grid.419836.10000 0001 2162 3360Health Science Research R&D Laboratories, Taisho Pharmaceutical Co., Ltd., 1-403 Yoshinomachi Kita-ku, Saitama City, Saitama 331-9530 Japan
| | - Masatsugu Shimomasuda
- grid.419836.10000 0001 2162 3360Research & Development Headquarters, Self-Medication, Taisho Pharmaceutical Co., Ltd., 3-24-1, Takada, Toshima-ku, Tokyo, 170-8633 Japan
| | - Mariko Nakamura
- grid.419627.fDepartment of Sports Research, Japan Institute of Sports Sciences, 3-15-1 Nishigaoka Kita-ku, Tokyo, 115-0056 Japan
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7
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Field AC, Harper LD, William Frederick Aldous J, Page RM. A commentary on soccer match-play simulations for applied research and practice. SCI MED FOOTBALL 2022; 7:93-105. [PMID: 35465842 DOI: 10.1080/24733938.2022.2070268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Soccer is a fast-growing area of research, demonstrated by a 10-fold increase in the number of PubMed articles derived from the search term 'soccer' between 2001 and 2021. The scope of contemporary soccer-related articles ranges from match-play observations to laboratory evaluations of performance. The activity profile of soccer match-play is variable and techniques to collect data within matches are limited. Soccer-specific simulations have been developed to simulate the evolving demands of match-play. The evolutionary designs of novel simulations provide a reproducible exercise stimulus for varying researcher and practitioner objectives. The applied researcher can utilise simulations to investigate the efficacy of nutritional interventions and environmental stress on performance, while assessing the physiological and biomechanical responses to representations of match-play. Practitioners can adopt simulations for rehabilitation to progressively facilitate return-to-play processes, while implementing extra top-up conditioning sessions for unused and partial-match players. However, there are complexities involved with the selection of varying simulations which are dependent on the research question or practical application. There also remains a paucity of published information to support researchers and practitioners in selecting from differing simulation models. To assist with researcher and practitioner interpretations, we present a commentary of the current simulations to inform decision-making processes for research and training purposes and enhance the application of future research. An objective scoring system was adopted for rating the research and practical applications of each simulation design. Overall scores of 22, 16 and 18 out of 36 were revealed for free-running (n=7), non-motorised- (n=4) and motorised-treadmill-based simulations (n=4), respectively.
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Affiliation(s)
- Adam C Field
- School of Human and Health Sciences, University of Huddersfield, Huddersfield, United Kingdom.,Nuffield Health, The Manchester Institute of Health and Performance, Manchester
| | - Liam D Harper
- School of Human and Health Sciences, University of Huddersfield, Huddersfield, United Kingdom
| | - Jeffrey William Frederick Aldous
- Department of Sport Science and Physical Activity, Institute of Sport and Physical Activity Research, University of Bedfordshire, Bedford, United Kingdom
| | - Richard M Page
- Department of Sport & Physical Activity, Edge Hill University, Ormskirk, United Kingdom
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8
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Coelho LGM, Ferreira-Júnior JB, Williams TB, Maia-Lima A, Borba DA, Silva CD, Coelho DB, Barros CLM, Prado LS, Silami-Garcia E. Head pre-cooling improves 5-km time-trial performance in male amateur runners in the heat. Scand J Med Sci Sports 2021; 31:1753-1763. [PMID: 33960538 DOI: 10.1111/sms.13985] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 04/15/2021] [Accepted: 04/26/2021] [Indexed: 01/26/2023]
Abstract
This study aimed to evaluate the effect of head pre-cooling on the 5-km time-trial performance of amateur runners in the heat. In a counterbalanced design, 15 male amateur runners (22.6 ± 3.5 y; VO2 max in heat 42.3 ± 4.4 mLO2 /kg/min) completed two 5-km time trials performed in the heat (35°C, 50% relative humidity). In one trial (HCOOL), participants underwent 20 min of head cooling in a temperate environment (23°C, 70% relative humidity) prior to exercise. In another trial (CON), exercise was preceded by 20 min of rest under the same temperature conditions. Exercise time was shorter in HCOOL (25 min and 36 s ± 3 min) compared to CON (27 ± 3 min; p = 0.02). Rectal temperature was reduced during the pre-exercise intervention in HCOOL (p < 0.001), but not in CON (p = 0.55). Relative changes in rectal temperature and mean head temperature were lower throughout HCOOL when compared with CON condition (p = 0.005 and p = 0.022, respectively). Mean skin temperature, heart rate, and rating of perceived exertion did not differ between HCOOL and CON conditions throughout exercise (p = 0.20, p = 0.52 and 0.31, respectively). Thermal comfort was lower in HCOOL condition in pre-exercise (p = 0.014) with no differences observed throughout exercise (p = 0.61). 5-km running performance in a hot environment was improved after a 20-min head cooling intervention, suggesting that this method may be practical as pre-cooling strategy and easily administered to both professional and amateur runners alike.
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Affiliation(s)
- Leonardo G M Coelho
- Federal Center of Technological Education of Minas Gerais, Divinopolis, Brazil
| | | | - Thomas B Williams
- Extreme Environments Laboratory (EEL), School of Sport, Health and Exercise Science, University of Portsmouth, Portsmouth, UK
| | - André Maia-Lima
- Federal Institute of Education Science and Technology of Roraima, Boa Vista, Brazil
| | - Diego A Borba
- Department of Human Movement Science, University of State of Minas Gerais, Ibirité, Brazil
| | - Cristiano D Silva
- Department of Physical Education, Institute of Life Sciences, Federal University of Juiz de Fora, Governador Valadares, Brazil
| | - Daniel B Coelho
- Sport Center, Federal University of Ouro Preto, Ouro Preto, Brazil
| | - Cristiano L M Barros
- College of Physical Education, Federal University of Uberlandia, Uberlandia, Brazil
| | - Luciano S Prado
- Sports Training Center (CTE), School of Physical Education, Physiotherapy and Occupational Therapy, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Emerson Silami-Garcia
- Sports Training Center (CTE), School of Physical Education, Physiotherapy and Occupational Therapy, Federal University of Minas Gerais, Belo Horizonte, Brazil.,School of Physical Education, Physiotherapy and Occupational Therapy, Federal University of Minas Gerais, Belo Horizonte, Brazil
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9
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Xu M, Wu Z, Dong Y, Qu C, Xu Y, Qin F, Wang Z, Nassis GP, Zhao J. A Mixed-Method Approach of Pre-Cooling Enhances High-Intensity Running Performance in the Heat. JOURNAL OF SPORTS SCIENCE AND MEDICINE 2021; 20:26-34. [PMID: 33707983 DOI: 10.52082/jssm.2021.26] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 12/01/2020] [Indexed: 01/08/2023]
Abstract
We investigated whether single or combined methods of pre-cooling could affect high-intensity exercise performance in a hot environment. Seven male athletes were subjected to four experimental conditions for 30 min in a randomised order. The four experimental conditions were: 1) wearing a vest cooled to a temperature of 4 ℃ (Vest), 2) consuming a beverage cooled to a temperature of 4 ℃ (Beverage), 3) simultaneous usage of vest and consumption of beverage (Mix), and 4) the control trial without pre-cooling (CON). Following those experimental conditions, they exercised at a speed of 80% VO2max until exhaustion in the heat (38.1 ± 0.6 ℃, 55.3 ± 0.3% RH). Heart rate (HR), rectal temperature (Tcore), skin temperature (Tskin), sweat loss (SL), urine specific gravity (USG), levels of sodium (Na+) and potassium (K+), rating of perceived exertion (RPE), thermal sensation (TS), and levels of blood lactic acid ([Bla]) were monitored. Performance was improved using the mixed pre-cooling strategy (648.43 ± 77.53 s, p = 0.016) compared to CON (509.14 ± 54.57 s). Tcore after pre-cooling was not different (Mix: 37.01 ± 0.27 ℃, Vest: 37.19 ± 0.33 ℃, Beverage: 37.03 ± 0.35 ℃) in all cooling conditions compared to those of CON (37.31 ±0.29 ℃). A similar Tcore values was achieved at exhaustion in all trials (from 38.10 ℃ to 39.00 ℃). No difference in the level of USG was observed between the conditions. Our findings suggest that pre-cooling with a combination of cold vest usage and cold fluid intake can improve performance in the heat.
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Affiliation(s)
- Minxiao Xu
- School of Kinesiology, Shanghai University of Sports, Shanghai, China.,Exercise Biological Center, China Institute of Sport Science, Beijing, China
| | - Zhaozhao Wu
- Exercise Biological Center, China Institute of Sport Science, Beijing, China.,Physical Education Department, Northwest University, Xi'an, China
| | - Yanan Dong
- Beijing Institute of Sport Science, Beijing, China
| | - Chaoyi Qu
- Exercise Biological Center, China Institute of Sport Science, Beijing, China.,School of Sport Science, Beijing Sport University, Beijing, China
| | - Yaoduo Xu
- Physical Education Department, Northwestern Poly-technical University, Xi'an, China
| | - Fei Qin
- Exercise Biological Center, China Institute of Sport Science, Beijing, China.,School of Physical Education, Jinan University, Guangzhou, China
| | - Zhongwei Wang
- School of Kinesiology, Shanghai University of Sports, Shanghai, China.,Exercise Biological Center, China Institute of Sport Science, Beijing, China
| | - George P Nassis
- Physical Education Department-(CEDU), United Arab Emirates University, Abu Dhabi, United Arab Emirates.,Department of Sports Science and Clinical Biomechanics, SDU Sport and Health Sciences Cluster (SHSC), University of Southern Denmark, Odense, Denmark
| | - Jiexiu Zhao
- Exercise Biological Center, China Institute of Sport Science, Beijing, China
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10
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Taylor L, Carter S, Stellingwerff T. Cooling at Tokyo 2020: the why and how for endurance and team sport athletes. Br J Sports Med 2020; 54:1243-1245. [PMID: 32816792 DOI: 10.1136/bjsports-2020-102638] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/15/2020] [Indexed: 02/07/2023]
Affiliation(s)
- Lee Taylor
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK .,Human Performance Research Centre, University of Technology Sydney, Sydney, New South Wales, Australia
| | - Sarah Carter
- Thermal Ergonomics Laboratory, Sydney School of Health Research, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Trent Stellingwerff
- Canadian Sport Institute, Victoria, British Columbia, Canada.,Department of Exercise Science, Physical & Health Education, University of Victoria, Victoria, British Columbia, Canada
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11
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Naito T, Haramura M, Muraishi K, Yamazaki M, Takahashi H. Impact of Ice Slurry Ingestion During Break-Times on Repeated-Sprint Exercise in the Heat. Sports Med Int Open 2020; 4:E45-E52. [PMID: 32395608 PMCID: PMC7205515 DOI: 10.1055/a-1139-1761] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 02/20/2020] [Accepted: 03/08/2020] [Indexed: 10/26/2022] Open
Abstract
The study aimed to investigate the effects of ice slurry ingestion during break times and half-time (HT) on repeated-sprint performance and core temperature in the heat. Seven males performed two different trials as follows: ice slurry (-1°C) or room temperature water ingestion at each break and HT break at 36.5°C, 50% relative humidity. Participants performed 30 sets of 1-min periods of repeated- sprint exercises protocol using a cycling ergometer. Each period consisted of 5 sec of maximal pedaling, 25 sec of pedaling with no workload, and 30 sec of rest; two sets of exercise periods were separated by 10 min of rest. Each break was implemented for 1 min after every 5 sets. The rectal temperature in ice slurry ingestion was significantly lower than that of the room temperature water at 45 set (p=0.04). Total and mean work done was greater in ice slurry ingestion compared to room temperature water ingestion (p < 0.05). These results suggested that ice slurry ingestion during break times and HT break may be an effective cooling strategy to attenuate the rise of core temperature in the second half of exercise and improve the repeated-sprint exercise capacity in the heat.
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Affiliation(s)
- Takashi Naito
- Department of Sports Research, Japan Institute of Sports Sciences, Kita-ku, Japan
| | - Miki Haramura
- Faculty of Sport Sciences, Waseda University, Shinjuku-ku,Japan.,Department of Sports Sciences, Japan Institute of Sports Sciences, Kita-ku, Japan
| | - Koji Muraishi
- Department of Sports Sciences, Japan Institute of Sports Sciences, Kita-ku, Japan.,Graduate School of Community and Health Services, Rikkyo University, Niiza-city, Japan
| | - Misa Yamazaki
- Department of Sports Sciences, Japan Institute of Sports Sciences, Kita-ku, Japan
| | - Hideyuki Takahashi
- Department of Sports Research, Japan Institute of Sports Sciences, Kita-ku, Japan
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12
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Rodríguez MÁ, Piedra JV, Sánchez-Fernández M, del Valle M, Crespo I, Olmedillas H. A Matter of Degrees: A Systematic Review of the Ergogenic Effect of Pre-Cooling in Highly Trained Athletes. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:E2952. [PMID: 32344616 PMCID: PMC7215649 DOI: 10.3390/ijerph17082952] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 04/14/2020] [Accepted: 04/21/2020] [Indexed: 01/10/2023]
Abstract
The current systematic review evaluated the effects of different pre-cooling techniques on sports performance in highly-trained athletes under high temperature conditions. PubMed/MEDLINE, EMBASE, Web of Science, CENTRAL, Scopus, and SPORTDiscus databases were searched from inception to December 2019. Studies performing pre-cooling interventions in non-acclimatized highly-trained athletes (>55 mL/kg/min of maximal oxygen consumption) under heat conditions (≥30 °C) were included. The searched reported 26 articles. Pre-cooling techniques can be external (exposure to ice water, cold packs, or cooling clothes), internal (intake of cold water or ice), or mixed. Cooling prior to exercise concluded increases in distance covered (1.5-13.1%), mean power output (0.9-6.9%), time to exhaustion (19-31.9%), work (0.1-8.5%), and mean peak torque (10.4-22.6%), as well as reductions in completion time (0.6-6.5%). Mixed strategies followed by cold water immersion seem to be the most effective techniques, being directly related with the duration of cooling and showing the major effects in prolonged exercise protocols. The present review showed that pre-cooling methods are an effective strategy to increase sports performance in hot environments. This improvement is associated with the body surface exposed and its sensibility, as well as the time of application, obtaining the best results in prolonged physical exercise protocols.
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Affiliation(s)
- Miguel Ángel Rodríguez
- Department of Functional Biology, Universidad de Oviedo, 33006 Oviedo, Spain; (M.Á.R.); (J.V.P.); (M.S.-F.); (I.C.)
| | - José Víctor Piedra
- Department of Functional Biology, Universidad de Oviedo, 33006 Oviedo, Spain; (M.Á.R.); (J.V.P.); (M.S.-F.); (I.C.)
| | - Mario Sánchez-Fernández
- Department of Functional Biology, Universidad de Oviedo, 33006 Oviedo, Spain; (M.Á.R.); (J.V.P.); (M.S.-F.); (I.C.)
| | - Miguel del Valle
- Department of Cellular Morphology and Biology, Universidad de Oviedo, 33006 Oviedo, Spain;
| | - Irene Crespo
- Department of Functional Biology, Universidad de Oviedo, 33006 Oviedo, Spain; (M.Á.R.); (J.V.P.); (M.S.-F.); (I.C.)
- Institute of Biomedicine, Universidad de León, 24071 León, Spain
| | - Hugo Olmedillas
- Department of Functional Biology, Universidad de Oviedo, 33006 Oviedo, Spain; (M.Á.R.); (J.V.P.); (M.S.-F.); (I.C.)
- Health Research Institute of the Principality of Asturias (ISPA), 33011 Oviedo, Spain
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13
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Taylor L, Stevens CJ, Thornton HR, Poulos N, Chrismas BCR. Limiting the Rise in Core Temperature During a Rugby Sevens Warm-Up With an Ice Vest. Int J Sports Physiol Perform 2019; 14:1212-1218. [PMID: 30840530 DOI: 10.1123/ijspp.2018-0821] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 01/17/2019] [Accepted: 02/05/2019] [Indexed: 10/27/2023]
Abstract
PURPOSE To determine how a cooling vest worn during a warm-up could influence selected performance (countermovement jump [CMJ]), physical (global positioning system [GPS] metrics), and psychophysiological (body temperature and perceptual) variables. METHODS In a randomized, crossover design, 12 elite male World Rugby Sevens Series athletes completed an outdoor (wet bulb globe temperature 23-27°C) match-specific externally valid 30-min warm-up wearing a phase-change cooling vest (VEST) and without (CONTROL), on separate occasions 7 d apart. CMJ was assessed before and after the warm-up, with GPS indices and heart rate monitored during the warm-ups, while core temperature (Tc; ingestible telemetric pill; n = 6) was recorded throughout the experimental period. Measures of thermal sensation (TS) and thermal comfort (TC) was obtained pre-warm-up and post-warm-up, with rating of perceived exertion (RPE) taken post-warm-ups. RESULTS Athletes in VEST had a lower ΔTc (mean [SD]: VEST = 1.3°C [0.1°C]; CONTROL = 2.0°C [0.2°C]) from pre-warm-up to post-warm-up (effect size; ±90% confidence limit: -1.54; ±0.62) and Tc peak (mean [SD]: VEST = 37.8°C [0.3°C]; CONTROL = 38.5°C [0.3°C]) at the end of the warm-up (-1.59; ±0.64) compared with CONTROL. Athletes in VEST demonstrated a decrease in ΔTS (-1.59; ±0.72) and ΔTC (-1.63; ±0.73) pre-warm-up to post-warm-up, with a lower RPE post-warm-up (-1.01; ±0.46) than CONTROL. Changes in CMJ and GPS indices were trivial between conditions (effect size < 0.2). CONCLUSIONS Wearing the vest prior to and during a warm-up can elicit favorable alterations in physiological (Tc) and perceptual (TS, TC, and RPE) warm-up responses, without compromising the utilized warm-up characteristics or physical-performance measures.
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14
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The Impact of an Ice Slurry-Induced Gastrointestinal Heat Sink on Gastrointestinal and Rectal Temperatures Following Exercise. Sports (Basel) 2019; 7:sports7090198. [PMID: 31461848 PMCID: PMC6784097 DOI: 10.3390/sports7090198] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 08/11/2019] [Accepted: 08/22/2019] [Indexed: 01/08/2023] Open
Abstract
Gastrointestinal temperature (Tgint) measurement with a telemetric pill (TP) is increasingly used in exercise science. Contact of cool water with a TP invalidates Tgint assessment. However, what effect a heat sink created in the proximity of a TP may have on the assessment of Tgint remains unknown. We examined the impact of an ice slurry-induced heat sink on Tgint and rectal temperature (Trec) following exercise. After 20 min of seating (20–22 °C, 25–40% relative humidity (RH)), 11 men completed two intersperse exercise periods (31–32 °C, 35% RH) at 75–80% of estimated maximal heart rate until a Trec increase of 1 °C above baseline level. Following the first exercise period, participants were seated for 45 min and ingested 7.5 g·kg−1 of thermoneutral water, whereas, following the second period, they ingested 7.5 g·kg−1 of ice slurry. Both Tgint and Trec were measured continuously. The TPs were swallowed 10 h prior to the experiments. A bias ≤0.27 °C was taken as an indication that Tgint and Trec provided similar core temperature indices. Mean biases and 95% limits of agreement during passive sitting, first exercise, water ingestion, second exercise, and ice slurry ingestion periods were 0.16 ± 0.53, 0.13 ± 0.41, 0.21 ± 0.70, 0.17 ± 0.50, and 0.18 ± 0.66 °C, respectively. The rates of decrease in Tgint and Trec did not differ between the water and ice slurry ingestion periods. Our results indicate that ice slurry ingestion following exercise does not impact TP-derived assessment of Tgint compared with Trec.
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15
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Brief in-play cooling breaks reduce thermal strain during football in hot conditions. J Sci Med Sport 2019; 22:912-917. [DOI: 10.1016/j.jsams.2019.04.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 04/11/2019] [Accepted: 04/28/2019] [Indexed: 11/19/2022]
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16
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The effects of lower body passive heating combined with mixed-method cooling during half-time on second-half intermittent sprint performance in the heat. Eur J Appl Physiol 2019; 119:1885-1899. [PMID: 31222380 DOI: 10.1007/s00421-019-04177-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 06/11/2019] [Indexed: 10/26/2022]
Abstract
PURPOSE This study examined the effects of combined cooling and lower body heat maintenance during half-time on second-half intermittent sprint performances. METHODS In a repeated measures design, nine males completed four intermittent cycling trials (32.1 ± 0.3 °C and 55.3 ± 3.7% relative humidity), with either one of the following half-time recovery interventions; mixed-method cooling (ice vest, ice slushy and hand cooling; COOL), lower body passive heating (HEAT), combined HEAT and COOL (COMB) and control (CON). Peak and mean power output (PPO and MPO), rectal (Tre), estimated muscle (Tes-Mus) and skin (TSK) temperatures were monitored throughout exercise. RESULTS During half-time, the decrease in Tre was substantially greater in COOL and COMB compared with CON and HEAT, whereas declines in Tes-Mus within HEAT and COMB were substantially attenuated compared with CON and COOL. The decrease in TSK was most pronounced in COOL compared with CON, HEAT and COMB. During second-half, COMB and HEAT resulted in a larger decrease in PPO and MPO during the initial stages of the second-half when compared to CON. In addition, COOL resulted in an attenuated decrease in PPO and MPO compared to COMB in the latter stages of second-half. CONCLUSION The maintenance of Tes-Mus following half-time was detrimental to prolonged intermittent sprint performance in the heat, even when used together with cooling.
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17
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Thomas G, Cullen T, Davies M, Hetherton C, Duncan B, Gerrett N. Independent or simultaneous lowering of core and skin temperature has no impact on self-paced intermittent running performance in hot conditions. Eur J Appl Physiol 2019; 119:1841-1853. [PMID: 31218440 PMCID: PMC6647662 DOI: 10.1007/s00421-019-04173-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 06/04/2019] [Indexed: 11/30/2022]
Abstract
Purpose To investigate the effects of lowering core (Tgi) and mean skin temperature (Tsk) concomitantly and independently on self-paced intermittent running in the heat. Methods 10 males (30.5 ± 5.8 years, 73.2 ± 14.5 kg, 176.9 ± 8.0 cm, 56.2 ± 6.6 ml/kg/min) completed four randomised 46-min self-paced intermittent protocols on a non-motorised treadmill in 34.4 ± 1.4 °C, 36.3 ± 4.6% relative humidity. 30-min prior to exercise, participants were cooled via either ice slurry ingestion (INT); a cooling garment (EXT); mixed-cooling (ice slurry and cooling garment concurrently) (MIX); or no-cooling (CON). Results At the end of pre-cooling and the start of exercise Tgi were lower during MIX (36.11 ± 1.3 °C) compared to CON (37.6 ± 0.5 °C) and EXT (36.9 ± 0.5 °C, p < 0.05). Throughout pre-cooling Tsk and thermal sensation were lower in MIX compared to CON and INT, but not EXT (p < 0.05). The reductions in thermophysiological responses diminished within 10–20 min of exercise. Despite lowering Tgi, Tsk, body temperature (Tb), and thermal sensation prior to exercise, the distances covered were similar (CON: 6.69 ± 1.08 km, INT: 6.96 ± 0.81 km, EXT: 6.76 ± 0.65 km, MIX 6.87 ± 0.70 km) (p > 0.05). Peak sprint speeds were also similar between conditions (CON: 25.6 ± 4.48 km/h, INT: 25.4 ± 3.6 km/h, EXT: 26.0 ± 4.94 km/h, MIX: 25.6 ± 3.58 km/h) (p > 0.05). Blood lactate, heart rate and RPE were similar between conditions (p > 0.05). Conclusion Lowering Tgi and Tsk prior to self-paced intermittent exercise did not improve sprint, or submaximal running performance. Electronic supplementary material The online version of this article (10.1007/s00421-019-04173-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- G Thomas
- School of Sport and Exercise Science, University of Worcester, Worcester, UK
| | - T Cullen
- School of Sport and Exercise Science, University of Worcester, Worcester, UK.,Centre for Sport Exercise and Life Sciences, Coventry University, Coventry, UK
| | - M Davies
- School of Sport and Exercise Science, University of Worcester, Worcester, UK
| | - C Hetherton
- School of Sport and Exercise Science, University of Worcester, Worcester, UK
| | - B Duncan
- School of Sport and Exercise Science, University of Worcester, Worcester, UK
| | - N Gerrett
- Faculty of Human Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands. .,Laboratory for Applied Human Physiology, Graduate School of Human Development and Environment, Kobe University, Kobe, Japan.
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18
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Taylor L, Thornton HR, Lumley N, Stevens CJ. Alterations in core temperature during World Rugby Sevens Series tournaments in temperate and warm environments †. Eur J Sport Sci 2018; 19:432-441. [PMID: 30305001 DOI: 10.1080/17461391.2018.1527949] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
PURPOSE To characterize player core temperature (Tc) across two separate World Rugby Sevens Series (WRSS) tournaments in temperate and warm environments. METHODS Tc was collected in seventeen playing members of one men's team competing at the Singapore (n = 12) and London (n = 11) WRSS tournaments. Exertional heat illness (EHI) symptoms, cooling strategy use, playing minutes and wet blub globe temperature (WBGT) were also collected. Linear mixed models and magnitude-based inferences assessed differences in Tc between all periods within-and between tournaments and were also used to assess the effect of WBGT and playing minutes on Tc. RESULTS Several players experienced Tc in excess of 38°C during warm-ups and 39°C during games. The highest mean Tc values were observed in the final game on all days and in Singapore Day Two, there were substantial game-on-game increases in mean Tc. These Tc responses were associated with playing minutes (effect size; ±90% CL = 0.38; ±0.20), although the effect of WBGT was trivial and unclear. Further, there were no differences in Tc between the two tournaments in the different environments. Despite high individual peak Tc values (Singapore 39.9°C; London 39.6°C); no signs/symptoms of EHI were reported, voluntary post-game cooling usage was minimal, and pre- and mid-cooling strategies were not implemented. CONCLUSIONS During WRSS matches, peak Tc values approached thresholds associated with EHI (>40°C) and exceeded those demonstrated to reduce repeated sprint performance (>39°C). Practitioners may consider the use of compatible cooling and heat acclimation strategies to minimize Tc increase and maximize player preparedness and recovery.
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Affiliation(s)
- Lee Taylor
- a Athlete Health and Performance Research Centre , ASPETAR, Qatar Orthopaedic and Sports Medicine Hospital , Doha , Qatar.,b School of Sport, Exercise and Health Sciences , Loughborough University , Loughborough , UK
| | - Heidi R Thornton
- c Newcastle Knights Rugby League Club , Newcastle , Australia.,d La Trobe Sport and Exercise Medicine Research Centre , La Trobe University , Melbourne , Australia
| | | | - Christopher J Stevens
- f School of Health and Human Sciences , Southern Cross University , Coffs Harbour , Australia
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