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Kwak M, Succi PJ, Benitez B, Mitchinson C, Samaan MA, Abel MG, Bergstrom HC. Comparison of Force, Neuromuscular, and Metabolic Responses During Sustained, Isometric Handgrip Holds to Failure Anchored to Low and High Perceptual Intensities in Men: An Exploratory Study. J Strength Cond Res 2024; 38:e405-e416. [PMID: 39072661 PMCID: PMC11296493 DOI: 10.1519/jsc.0000000000004812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
ABSTRACT Kwak, M, Succi, PJ, Benitez, B, Mitchinson, C, Samaan, MA, Abel, MG, and Bergstrom, HC. Comparison of force, neuromuscular, and metabolic responses during sustained, isometric handgrip holds to failure anchored to low and high perceptual intensities in men: An exploratory study. J Strength Cond Res 38(8): e405-e416, 2024-This study examined the responses of force alterations, relative to critical force (CF), neuromuscular parameters, and muscle oxygenation (SmO2) for isometric handgrip holds to failure (HTF) anchored to ratings of perceived exertion (RPE) of 3 and 7. Twelve men completed pre-maximal voluntary isometric contractions (pre-MVIC), submaximal HTF at 4 percentages of pre-MVIC, HTF at RPE = 3 and 7, and post-MVIC. Mechanomyograpic (MMG) signals and SmO2 were recorded during the RPE HTF. Analyses included paired-samples t-tests and repeated-measures ANOVAs at an alpha level of p ≤ 0.05. Time to task failure was not different between RPE 3 (478.7 ± 196.6 s) and RPE 7 (495.8 ± 173.8 s). Performance fatigability (PF) and MMG amplitude (AMP) were greater for RPE 7 (PF: 37.9 ± 12.9%; MMG AMP: 15.7 ± 7.4% MVIC) than RPE 3 (PF: 30.0 ± 14.5%; MMG AMP: 10.2 ± 6.5% MVIC), but MMG mean power frequency (MPF) was greater for RPE 3 (146.2 ± 31.1% MVIC) than RPE 7 (128.8 ± 23.0% MVIC). There were RPE-dependent decreases in force (p ≤ 0.01) across 3 discernable phases during the HTF. There were decreases in MMG AMP across time for both RPEs, but there were no significant changes in MMG MPF or SmO2. There were overall similar motor unit control strategies and local metabolic demand between RPEs. The majority of the HTF performed below CF at RPE 3 and 7 indicated CF did not reflect the highest sustainable force. When prescribing isometric exercise anchored to RPE, practitioners should be aware of the magnitude of force loss and relative intensity of the task to be sure desired training loads are met.
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Affiliation(s)
- Minyoung Kwak
- Department of Kinesiology and Health Promotion, The University of Kentucky, Lexington, KY, USA
| | - Pasquale J. Succi
- Department of Kinesiology and Health Promotion, The University of Kentucky, Lexington, KY, USA
| | - Brian Benitez
- Department of Kinesiology and Health Promotion, The University of Kentucky, Lexington, KY, USA
| | - Clara Mitchinson
- Department of Kinesiology and Health Promotion, The University of Kentucky, Lexington, KY, USA
| | - Michael A. Samaan
- Department of Kinesiology and Health Promotion, The University of Kentucky, Lexington, KY, USA
| | - Mark G. Abel
- Department of Kinesiology and Health Promotion, The University of Kentucky, Lexington, KY, USA
| | - Haley C. Bergstrom
- Department of Kinesiology and Health Promotion, The University of Kentucky, Lexington, KY, USA
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John K, Kathuria S, Peel J, Page J, Aitkenhead R, Felstead A, Heffernan SM, Jeffries O, Tallent J, Waldron M. Caffeine ingestion compromises thermoregulation and does not improve cycling time to exhaustion in the heat amongst males. Eur J Appl Physiol 2024; 124:2489-2502. [PMID: 38568259 PMCID: PMC11322244 DOI: 10.1007/s00421-024-05460-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 03/04/2024] [Indexed: 08/16/2024]
Abstract
PURPOSE Caffeine is a commonly used ergogenic aid for endurance events; however, its efficacy and safety have been questioned in hot environmental conditions. The aim of this study was to investigate the effects of acute caffeine supplementation on cycling time to exhaustion and thermoregulation in the heat. METHODS In a double-blind, randomised, cross-over trial, 12 healthy caffeine-habituated and unacclimatised males cycled to exhaustion in the heat (35 °C, 40% RH) at an intensity associated with the thermoneutral gas exchange threshold, on two separate occasions, 60 min after ingesting caffeine (5 mg/kg) or placebo (5 mg/kg). RESULTS There was no effect of caffeine supplementation on cycling time to exhaustion (TTE) (caffeine; 28.5 ± 8.3 min vs. placebo; 29.9 ± 8.8 min, P = 0.251). Caffeine increased pulmonary oxygen uptake by 7.4% (P = 0.003), heat production by 7.9% (P = 0.004), whole-body sweat rate (WBSR) by 21% (P = 0.008), evaporative heat transfer by 16.5% (P = 0.006) and decreased estimated skin blood flow by 14.1% (P < 0.001) compared to placebo. Core temperature was higher by 0.6% (P = 0.013) but thermal comfort decreased by - 18.3% (P = 0.040), in the caffeine condition, with no changes in rate of perceived exertion (P > 0.05). CONCLUSION The greater heat production and storage, as indicated by a sustained increase in core temperature, corroborate previous research showing a thermogenic effect of caffeine ingestion. When exercising at the pre-determined gas exchange threshold in the heat, 5 mg/kg of caffeine did not provide a performance benefit and increased the thermal strain of participants.
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Affiliation(s)
- Kevin John
- Research Institute for Sport and Exercise, University of Canberra, Canberra, Australia
- Applied Sports Science Technology and Medicine Research Centre (A-STEM), Faculty of Science and Engineering, Bay Campus, Swansea University, Swansea, Wales, SA1 8EN, UK
| | - Sayyam Kathuria
- Applied Sports Science Technology and Medicine Research Centre (A-STEM), Faculty of Science and Engineering, Bay Campus, Swansea University, Swansea, Wales, SA1 8EN, UK
| | - Jenny Peel
- Applied Sports Science Technology and Medicine Research Centre (A-STEM), Faculty of Science and Engineering, Bay Campus, Swansea University, Swansea, Wales, SA1 8EN, UK
| | - Joe Page
- Applied Sports Science Technology and Medicine Research Centre (A-STEM), Faculty of Science and Engineering, Bay Campus, Swansea University, Swansea, Wales, SA1 8EN, UK
| | - Robyn Aitkenhead
- Applied Sports Science Technology and Medicine Research Centre (A-STEM), Faculty of Science and Engineering, Bay Campus, Swansea University, Swansea, Wales, SA1 8EN, UK
| | - Aimee Felstead
- Applied Sports Science Technology and Medicine Research Centre (A-STEM), Faculty of Science and Engineering, Bay Campus, Swansea University, Swansea, Wales, SA1 8EN, UK
| | - Shane M Heffernan
- Applied Sports Science Technology and Medicine Research Centre (A-STEM), Faculty of Science and Engineering, Bay Campus, Swansea University, Swansea, Wales, SA1 8EN, UK
| | - Owen Jeffries
- School of Biomedical, Nutritional and Sport Sciences, Newcastle University, Newcastle Upon Tyne, UK
| | - Jamie Tallent
- School of Sport, Rehabilitation, and Exercise Sciences, University of Essex, Colchester, UK
- Department of Physiotherapy, Faculty of Medicine, Nursing and Health Sciences, School of Primary and Allied Health Care, Monash University, Clayton, Australia
| | - Mark Waldron
- Applied Sports Science Technology and Medicine Research Centre (A-STEM), Faculty of Science and Engineering, Bay Campus, Swansea University, Swansea, Wales, SA1 8EN, UK.
- Welsh Institute of Performance Science, Swansea University, Swansea, UK.
- School of Health and Behavioural Sciences, University of the Sunshine Coast, Sippy Down, QLD, Australia.
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Roriz M, Brito J, Teixeira FJ, Spyrou K, Teixeira VH. The effect of menthol rinsing before intermittent exercise on physiological, physical, and thermo-behavioral responses of male football referees in hot and humid environment. Front Sports Act Living 2024; 6:1334739. [PMID: 38318484 PMCID: PMC10839052 DOI: 10.3389/fspor.2024.1334739] [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: 11/07/2023] [Accepted: 01/04/2024] [Indexed: 02/07/2024] Open
Abstract
Introduction In the current experiment, we aimed to evaluate whether eliciting pre-exercise non-thermal cooling sensations would alter perceptual measures, and physical and physiological responses in football referees. Methods Nine highly trained male football referees undertook two 45-minute intermittent exercise protocols in hot and humid conditions (34.2 ± 0.6°C, 62.5 ± 1.0% relative humidity). In a randomized counterbalanced crossover design, 1 of 2 beverages were given before the warm-up: a 0.01% menthol solution or a placebo noncaloric solution. Physical performance was quantified as total distance covered in each of the three 15-minute exercise blocks. Core temperature, heart rate, thermal sensation and thermal comfort were measured at rest and after each exercise block. Results No changes were observed between trials and over time for distance covered. No main effect of mouth rinse was observed for core temperature and heart rate, but both increased over time in all conditions (P < 0.001). Thermal sensation and thermal comfort were significantly improved with menthol after mouth-rinsing (P < 0.05), but with no differences at any other time-point. Discussion These results indicate that non-thermal cooling oral stimuli provide immediate behavioral changes but may not influence physiological or physical responses in football referees, during intermittent exercise in hot and humid environments. Clinical Trial Registration www.clinicaltrials.gov, identifier NCT05632692.
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Affiliation(s)
- Maria Roriz
- Faculty of Nutrition and Food Sciences, University of Porto (FCNAUP), Porto, Portugal
| | - João Brito
- Portugal Football School, Portuguese Football Federation, Oeiras, 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
| | - Konstantinos Spyrou
- UCAM Research Center for High Performance Sport, UCAM Universidad Católica de Murcia, Murcia, Spain
- Facultad de Deporte, UCAM Universidad Católica de Murcia, Murcia, Spain
| | - Vitor Hugo Teixeira
- Faculty of Nutrition and Food Sciences, University of Porto (FCNAUP), 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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Yoder HA, Mulholland AM, MacDonald HV, Wingo JE. Acute work rate adjustments during high-intensity interval training in a hot and temperate environment. Appl Physiol Nutr Metab 2023; 48:962-973. [PMID: 37657087 DOI: 10.1139/apnm-2023-0144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/03/2023]
Abstract
Heart rate drifts upward over time during interval exercise and during exercise in hot conditions. As such, work rate must be lowered to maintain target heart rate. The purpose was to characterize acute work rate adjustments during high-intensity interval training based on target heart rate. Seven humans (three females) completed five study visits: a graded exercise test on a cycle ergometer to measure maximal heart rate (HRmax) in ∼22 °C and four trials performed in ∼22 °C (TEMP) or ∼35 °C (HOT), consisting of an 8 min warm-up at 70% HRmax followed by one (15TEMP and 15HOT) or five (43TEMP and 43HOT) rounds of high-intensity interval training (one round = 4 min work at 90% HRmax and 3 min recovery at 70% HRmax) totaling 15 min or 43 min of exercise, respectively. Work rate was lowered 33 ± 20 W (p = 0.005) in 43TEMP and 56 ± 30 W (p = 0.003) in 43HOT between the first and fifth work intervals. Thermal strain (0.2 °C higher rectal temperature, p = 0.01) and cardiovascular strain (6 beats·min-1 larger increase in heart rate from first to fifth recovery interval, p = 0.01) were greater in 43HOT versus 43TEMP. Using target heart rate during high-intensity interval training may reduce the training stimulus, especially in hot environments, but it may also limit thermal strain and enable participants to complete the prescribed workout despite the heat.
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Affiliation(s)
- Hillary A Yoder
- Department of Kinesiology, The University of Alabama, Tuscaloosa, AL, USA
- Department of Kinesiology, New Mexico State University, Las Cruces, NM, USA
| | - Anne M Mulholland
- Department of Kinesiology, The University of Alabama, Tuscaloosa, AL, USA
| | - Hayley V MacDonald
- Department of Kinesiology, The University of Alabama, Tuscaloosa, AL, USA
| | - Jonathan E Wingo
- Department of Kinesiology, The University of Alabama, Tuscaloosa, AL, USA
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Henderson MJ, Grandou C, Chrismas BCR, Coutts AJ, Impellizzeri FM, Taylor L. Core Body Temperatures in Intermittent Sports: A Systematic Review. Sports Med 2023; 53:2147-2170. [PMID: 37526813 PMCID: PMC10587327 DOI: 10.1007/s40279-023-01892-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/11/2023] [Indexed: 08/02/2023]
Abstract
BACKGROUND Hyperthermia (and associated health and performance implications) can be a significant problem for athletes and teams involved in intermittent sports. Quantifying the highest thermal strain (i.e. peak core body temperature [peak Tc]) from a range of intermittent sports would enhance our understanding of the thermal requirements of sport and assist in making informed decisions about training or match-day interventions to reduce thermally induced harm and/or performance decline. OBJECTIVE The objective of this systematic review was to synthesise and characterise the available thermal strain data collected in competition from intermittent sport athletes. METHODS A systematic literature search was performed on Web of Science, MEDLINE, and SPORTDiscus to identify studies up to 17 April 2023. Electronic databases were searched using a text mining method to provide a partially automated and systematic search strategy retrieving terms related to core body temperature measurement and intermittent sport. Records were eligible if they included core body temperature measurement during competition, without experimental intervention that may influence thermal strain (e.g. cooling), in healthy, adult, intermittent sport athletes at any level. Due to the lack of an available tool that specifically includes potential sources of bias for physiological responses in descriptive studies, a methodological evaluation checklist was developed and used to document important methodological considerations. Data were not meta-analysed given the methodological heterogeneity between studies and therefore were presented descriptively in tabular and graphical format. RESULTS A total of 34 studies were selected for review; 27 were observational, 5 were experimental (2 parallel group and 3 repeated measures randomised controlled trials), and 2 were quasi-experimental (1 parallel group and 1 repeated measures non-randomised controlled trial). Across all included studies, 386 participants (plus participant numbers not reported in two studies) were recruited after accounting for shared data between studies. A total of 4 studies (~ 12%) found no evidence of hyperthermia, 24 (~ 71%) found evidence of 'modest' hyperthermia (peak Tc between 38.5 and 39.5 °C), and 6 (~ 18%) found evidence of 'marked' hyperthermia (peak Tc of 39.5 °C or greater) during intermittent sports competition. CONCLUSIONS Practitioners and coaches supporting intermittent sport athletes are justified to seek interventions aimed at mitigating the high heat strain observed in competition. More research is required to determine the most effective interventions for this population that are practically viable in intermittent sports settings (often constrained by many competing demands). Greater statistical power and homogeneity among studies are required to quantify the independent effects of wet bulb globe temperature, competition duration, sport and level of competition on peak Tc, all of which are likely to be key modulators of the thermal strain experienced by competing athletes. REGISTRATION This systematic review was registered on the Open Science Framework ( https://osf.io/vfb4s ; https://doi.org/10.17605/OSF.IO/EZYFA , 4 January 2021).
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Affiliation(s)
- Mitchell J Henderson
- School of Sport, Exercise and Rehabilitation, Faculty of Health, University of Technology Sydney (UTS), Sydney, Australia.
- Human Performance Research Centre, University of Technology Sydney (UTS), Sydney, Australia.
| | - Clementine Grandou
- School of Sport, Exercise and Rehabilitation, Faculty of Health, University of Technology Sydney (UTS), Sydney, Australia
- Human Performance Research Centre, University of Technology Sydney (UTS), Sydney, Australia
| | - Bryna C R Chrismas
- Department of Physical Education, College of Education, Qatar University, Doha, Qatar
| | - Aaron J Coutts
- School of Sport, Exercise and Rehabilitation, Faculty of Health, University of Technology Sydney (UTS), Sydney, Australia
- Human Performance Research Centre, University of Technology Sydney (UTS), Sydney, Australia
| | - Franco M Impellizzeri
- School of Sport, Exercise and Rehabilitation, Faculty of Health, University of Technology Sydney (UTS), Sydney, Australia
- Human Performance Research Centre, University of Technology Sydney (UTS), Sydney, Australia
| | - Lee Taylor
- School of Sport, Exercise and Rehabilitation, Faculty of Health, University of Technology Sydney (UTS), Sydney, Australia
- Human Performance Research Centre, University of Technology Sydney (UTS), Sydney, Australia
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
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Changes in pacing variation with increasing race duration in ultra-triathlon races. Sci Rep 2023; 13:3692. [PMID: 36878948 PMCID: PMC9986668 DOI: 10.1038/s41598-023-30932-1] [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: 04/16/2022] [Accepted: 03/03/2023] [Indexed: 03/08/2023] Open
Abstract
Despite the increasing scientific interest in the relationship between pacing and performance in endurance sports, little information is available about pacing and pacing variation in ultra-endurance events such as ultra-triathlons. Therefore, we aimed to investigate the trends of pacing, pacing variation, the influence of age, sex, and performance level in ultra-triathlons of different distances. We analysed 969 finishers (849 men, 120 women) in 46 ultra-triathlons longer than the original Ironman® distance (e.g., Double-, Triple-, Quintuple- and Deca Iron ultra-triathlons) held from 2004 to 2015. Pacing speed was calculated for every cycling and running lap. Pacing variation was calculated as the coefficient of variation (%) between the average speed of each lap. Performance level (i.e., fast, moderate, slow) was defined according to the 33.3 and 66.6 percentile of the overall race time. A multivariate analysis (two-way ANOVA) was applied for the overall race time as the dependent variable with 'sex' and 'age group' as independent factors. Another multivariate model with 'age' and 'sex' as covariates (two-way ANCOVA) was applied with pacing variation (cycling and running) as the dependent variable with 'race' and 'performance level' as independent factors. Different pacing patterns were observed by event and performance level. The general pacing strategy applied was a positive pacing. In Double and Triple Iron ultra-triathlon, faster athletes paced more evenly with less variation than moderate or slower athletes. The variation in pacing speed increased with the length of the race. There was no significant difference in pacing variation between faster, moderate, and slower athletes in Quintuple and Deca Iron ultra-triathlon. Women had a slower overall performance than men. The best overall times were achieved at the age of 30-39 years. Successful ultra-triathlon athletes adapted a positive pacing strategy in all race distances. The variation in pacing speed increased with the length of the race. In shorter ultra-triathlon distances (i.e., Double and Triple Iron ultra-triathlon), faster athletes paced more evenly with less variation than moderate or slower athletes. In longer ultra-triathlon distances (i.e., Quintuple and Deca Iron ultra-triathlon), there was no significant difference in pacing variation between faster, moderate, and slower athletes.
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Smith RW, Housh TJ, Anders JPV, Neltner TJ, Arnett JE, Schmidt RJ, Johnson GO. Application of the Ratings of Perceived Exertion-Clamp Model to Examine the Effects of Joint Angle on the Time Course of Torque and Neuromuscular Responses During a Sustained, Isometric Forearm Flexion to Task Failure. J Strength Cond Res 2022; 37:1023-1033. [PMID: 36730581 DOI: 10.1519/jsc.0000000000004357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Robert W Smith
- Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, Lincoln, Nebraska
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8
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Moore AR, Olson M. Exercise Task Characteristics Influence Time Perception During Vigorous Exercise. TIMING & TIME PERCEPTION 2022. [DOI: 10.1163/22134468-bja10067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Abstract
The passage of time is observed subjectively, and changes rate based on attentional or physiological stimuli. Self-adjusted exercise typically leads to the experience that time is progressing more slowly than it really is, but only when intensity is sufficiently high. This study was designed to determine if high exercise intensity at a fixed work rate would lead to differences in subjective timing. Subjects (26 total; 17 men/ 9 women) completed a maximal exercise test on a Velotron cycle ergometer until volitional exhaustion. A time production task was completed at baseline prior to exercise, and during each 3-min stage. Heart rate (HR) was assessed continuously. Time perception ratio (actual time divided by perceived time) was compared at baseline, during light exercise (40 W), and during the first stage at which age-predicted HRmax was considered vigorous (76–90% HRmax), using a repeated-measures analysis of variance (ANOVA). The result of the ANOVA was significant, F1.63,39 = 6.19, p = 0.007, η2 = 0.21. Bonferroni-adjusted post-hoc comparisons showed that the time perception ratio was higher during vigorous exercise (1.21 ± 0.34) compared to baseline (1.06 ± 0.19; p = 0.028) and light (1.09 ± 0.27; p = 0.048) exercise. Unlike several similar studies finding that subjective time increases at higher exercise intensities, the results of this study indicate the opposite effect at a fixed vigorous-intensity work rate. The motivational nature of the task and unique attentional factors associated with it are likely explanations for the deviation from earlier reports.
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Affiliation(s)
- Andrew R. Moore
- Department of Kinesiology, Augusta University, Augusta, GA 30909, USA
| | - Maddie Olson
- Department of Kinesiology, Augusta University, Augusta, GA 30909, USA
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Teunissen LPJ, Jansen KMB, Janssen E, Kingma BRM, de Korte JQ, Eijsvogels TMH. Impact of different climatic conditions on peak core temperature of elite athletes during exercise in the heat: a Thermo Tokyo simulation study. BMJ Open Sport Exerc Med 2022; 8:e001313. [PMID: 35813127 PMCID: PMC9234798 DOI: 10.1136/bmjsem-2022-001313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2022] [Indexed: 11/04/2022] Open
Abstract
Objectives To evaluate how separate and combined climatic parameters affect peak core temperature during exercise in the heat using computer simulations fed with individual data. Methods The impact of eight environmental conditions on rectal temperature (Tre) was determined for exercise under heat stress using the Fiala-thermal-Physiology-and-Comfort simulation model. Variations in ambient temperature (Ta±6°C), relative humidity (RH±15%) and solar radiation (SR+921 W/m2) were assessed in isolation and combination (worst-case/best-case scenarios) and compared with baseline (Ta32°C, RH 75%, SR 0 W/m2). The simulation model was fed with personal, anthropometric and individual exercise characteristics. Results 54 athletes exercised for 46±10 min at baseline conditions and achieved a peak core temperature of 38.9±0.5°C. Simulations at a higher Ta (38°C) and SR (921 W/m2) resulted in a higher peak Tre compared with baseline (+0.6±0.3°C and +0.5±0.2°C, respectively), whereas a higher RH (90%) hardly affected peak Tre (+0.1±0.1°C). A lower Ta (26°C) and RH (60%) reduced peak Tre by −0.4±0.2°C and a minor −0.1±0.1°C, respectively. The worst-case simulation yielded a 1.5±0.4°C higher Tre than baseline and 2.0±0.7°C higher than the best-case condition. Conclusion Combined unfavourable climatic conditions produce a greater increase in peak core temperature than the sum of its parts in elite athletes exercising in the heat.
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Affiliation(s)
- Lennart P J Teunissen
- Department of Design Engineering, Delft University of Technology, Delft, The Netherlands
| | - Kaspar M B Jansen
- Department of Design Engineering, Delft University of Technology, Delft, The Netherlands
| | - Emiel Janssen
- Department of Design Engineering, Delft University of Technology, Delft, The Netherlands
| | - Boris R M Kingma
- Department of Training & Performance Innovations, TNO, Unit Defence, Safety & Security, Soesterberg, The Netherlands
| | - Johannus Q de Korte
- Radboud Institute for Health Sciences, Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Thijs M H Eijsvogels
- Radboud Institute for Health Sciences, Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
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Bok D, Rakovac M, Foster C. An Examination and Critique of Subjective Methods to Determine Exercise Intensity: The Talk Test, Feeling Scale, and Rating of Perceived Exertion. Sports Med 2022; 52:2085-2109. [PMID: 35507232 DOI: 10.1007/s40279-022-01690-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/04/2022] [Indexed: 10/18/2022]
Abstract
Prescribing exercise intensity is crucial in achieving an adequate training stimulus. While numerous objective methods exist and are used in practical settings for exercise intensity prescription, they all require anchor measurements that are derived from a maximal or submaximal graded exercise test or a series of submaximal or supramaximal exercise bouts. Conversely, self-reported subjective methods such as the Talk Test (TT), Feeling Scale (FS) affect rating, and rating of perceived exertion (RPE) do not require exercise testing prior to commencement of the exercise training and therefore appear as more practical tools for exercise intensity prescription. This review is intended to provide basic information on reliability and construct validity of the TT, FS, and RPE measurements to delineate intensity domains. The TT and RPE appear to be valid measures of both the ventilatory threshold and the respiratory compensation threshold. Although not specifically examined, the FS showed tendency to demarcate ventilatory threshold, but its validity to demarcate the respiratory compensation threshold is limited. Equivocal stage of the TT, RPE of 10-11, and FS ratings between fairly good (+ 1) and good (+ 3) are reflective of the ventilatory threshold, while negative stage of the TT, RPE of 13-15, and FS ratings around neutral (0) are reflective of the respiratory compensation threshold. The TT and RPE can effectively be used to elicit homeostatic disturbances consistent with the moderate, heavy, and severe intensity domains, while physiological responses to constant FS ratings show extensive variability around ventilatory threshold to be considered effective in demarcating transition between moderate and heavy intensity domains.
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Affiliation(s)
- Daniel Bok
- Faculty of Kinesiology, University of Zagreb, Zagreb, Croatia.
| | - Marija Rakovac
- Faculty of Kinesiology, University of Zagreb, Zagreb, Croatia
| | - Carl Foster
- Department of Exercise and Sport Science, University of Wisconsin-La Crosse, La Crosse, WI, USA
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Noakes TD. What Is the Evidence That Dietary Macronutrient Composition Influences Exercise Performance? A Narrative Review. Nutrients 2022; 14:862. [PMID: 35215511 PMCID: PMC8875928 DOI: 10.3390/nu14040862] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 01/25/2022] [Accepted: 01/25/2022] [Indexed: 01/06/2023] Open
Abstract
The introduction of the needle muscle biopsy technique in the 1960s allowed muscle tissue to be sampled from exercising humans for the first time. The finding that muscle glycogen content reached low levels at exhaustion suggested that the metabolic cause of fatigue during prolonged exercise had been discovered. A special pre-exercise diet that maximized pre-exercise muscle glycogen storage also increased time to fatigue during prolonged exercise. The logical conclusion was that the athlete's pre-exercise muscle glycogen content is the single most important acutely modifiable determinant of endurance capacity. Muscle biochemists proposed that skeletal muscle has an obligatory dependence on high rates of muscle glycogen/carbohydrate oxidation, especially during high intensity or prolonged exercise. Without this obligatory carbohydrate oxidation from muscle glycogen, optimum muscle metabolism cannot be sustained; fatigue develops and exercise performance is impaired. As plausible as this explanation may appear, it has never been proven. Here, I propose an alternate explanation. All the original studies overlooked one crucial finding, specifically that not only were muscle glycogen concentrations low at exhaustion in all trials, but hypoglycemia was also always present. Here, I provide the historical and modern evidence showing that the blood glucose concentration-reflecting the liver glycogen rather than the muscle glycogen content-is the homeostatically-regulated (protected) variable that drives the metabolic response to prolonged exercise. If this is so, nutritional interventions that enhance exercise performance, especially during prolonged exercise, will be those that assist the body in its efforts to maintain the blood glucose concentration within the normal range.
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Affiliation(s)
- Timothy David Noakes
- Department of Applied Design, Cape Peninsula University of Technology, Cape Town 8000, South Africa
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Smith RW, Housh TJ, Anders JPV, Neltner TJ, Arnett JE, Schmidt RJ, Johnson GO. Time course of changes in torque and neuromuscular parameters during a sustained isometric forearm flexion task to fatigue anchored to a constant rating of perceived exertion. JOURNAL OF MUSCULOSKELETAL & NEURONAL INTERACTIONS 2022; 22:455-464. [PMID: 36458383 PMCID: PMC9716304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE This study examined the time course of changes in torque and electromyographic (EMG) and mechanomyographic (MMG) responses during a sustained isometric task anchored to a constant perception of exertion (RPE). METHODS Twelve college-aged men performed an isometric forearm flexion task to failure anchored to RPE=7 (OMNI-RES scale). The amplitude (AMP) and frequency (MPF) of the EMG and MMG signals from the biceps brachii were recorded. Repeated measures ANOVAs were used to examine differences for the normalized (%MVIC) torque and neuromuscular parameters. RESULTS The time to task failure (TTF) was 678.0±468.1s. Torque decreased significantly (p<0.001, ηp2=0.774) across time and all subjects reduced torque to zero. Post-hoc comparisons indicated that the torque values from 20-100% TTF were less than the value at 10% TTF. There were no significant (p>0.05) changes from 10-100% TTF for the EMG and MMG parameters. CONCLUSION We hypothesize that RPE was maintained by various mechanisms throughout the task: group III/IV afferent neurons, adequate blood flow, and a combination of reduced contractile efficiency, collective afferent feedback (group III/IV afferents) from muscles involved with forearm flexion, and motivation that resulted in an initial decrease, plateau, and final decline in torque to zero, respectively.
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Affiliation(s)
- Robert W. Smith
- Department of Nutrition and Human Sciences, University of Nebraska – Lincoln, Lincoln, USA,Corresponding author: Robert W. Smith, 540 N 16th Street, Lincoln, NE 68508-0626, USA E-mail:
| | - Terry J. Housh
- Department of Nutrition and Human Sciences, University of Nebraska – Lincoln, Lincoln, USA
| | - John Paul V. Anders
- Department of Nutrition and Human Sciences, University of Nebraska – Lincoln, Lincoln, USA
| | - Tyler J. Neltner
- Department of Nutrition and Human Sciences, University of Nebraska – Lincoln, Lincoln, USA
| | - Jocelyn E. Arnett
- Department of Nutrition and Human Sciences, University of Nebraska – Lincoln, Lincoln, USA
| | - Richard J. Schmidt
- Department of Nutrition and Human Sciences, University of Nebraska – Lincoln, Lincoln, USA
| | - Glen O. Johnson
- Department of Nutrition and Human Sciences, University of Nebraska – Lincoln, Lincoln, USA
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13
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Kaiser BW, Kruse KK, Gibson BM, Santisteban KJ, Larson EA, Wilkins BW, Jones AM, Halliwill JR, Minson CT. The impact of elevated body core temperature on critical power as determined by a 3-min all-out test. J Appl Physiol (1985) 2021; 131:1543-1551. [DOI: 10.1152/japplphysiol.00253.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The parameters of the power-duration relationship (critical power and W′) estimated by a 3-min all-out test were not altered by elevated body core temperature as compared with a thermoneutral condition.
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Affiliation(s)
- Brendan W. Kaiser
- Department of Human Physiology, University of Oregon, Eugene, Oregon
| | - Ka'eo K. Kruse
- Department of Human Evolutionary Biology, Harvard University, Cambridge, Massachusetts
| | - Brandon M. Gibson
- Department of Human Physiology, University of Oregon, Eugene, Oregon
| | | | - Emily A. Larson
- Department of Human Physiology, University of Oregon, Eugene, Oregon
| | - Brad W. Wilkins
- Department of Human Physiology, University of Oregon, Eugene, Oregon
- Department of Human Physiology, Gonzaga University, Spokane, Washington
| | - Andrew M. Jones
- Department of Sport and Health Sciences, University of Exeter, St. Luke’s Campus, Exeter, United Kingdom
| | - John R. Halliwill
- Department of Human Physiology, University of Oregon, Eugene, Oregon
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14
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Seeberg TM, Kocbach J, Danielsen J, Noordhof DA, Skovereng K, Meyer F, Sandbakk Ø. Physiological and Biomechanical Responses to Cross-Country Skiing in Varying Terrain: Low- vs. High-Intensity. Front Physiol 2021; 12:741573. [PMID: 34707511 PMCID: PMC8543002 DOI: 10.3389/fphys.2021.741573] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 09/07/2021] [Indexed: 11/13/2022] Open
Abstract
The purposes of our study were to investigate the physiological and biomechanical responses to low-intensity (LI) and high-intensity (HI) roller ski skating on varying terrain and compare these responses between training intensities. Nine elite male skiers performed treadmill roller skiing consisting of two 21 min sessions (7 × 3 min laps) at LI and HI with the same set inclines and intensity-dependent speeds (LI/HI: distance: 5.8/7.5 km, average speed: 16.7/21.3 km/h). Physiological and biomechanical variables were measured continuously, and each movement cycle and sub-technique employed were detected and classified with a machine learning model. Both the LI and HI sessions induced large terrain-dependent fluctuations (relative to the maximal levels) in heart rate (HR, 17.7 vs. 12.2%-points), oxygen uptake (V.O2, 33.0 vs. 31.7%-points), and muscle oxygen saturation in the triceps brachii (23.9 vs. 33.4%-points) and vastus lateralis (12.6 vs. 24.3%-points). A sub-technique dependency in relative power contribution from poles and skis exhibited a time-dependent shift from Lap 1 to Lap 7 toward gradually more ski power (6.6 vs. 7.8%-points, both p < 0.01). The terrain-dependent fluctuations did not differ between LI and HI for V.O2 (p = 0.50), whereas HR fluctuated less (p < 0.01) and displayed a time-dependent increase from Lap 2 to Lap 7 (7.8%-points, p > 0.01) during HI. Oxygen saturation shifted 2.4% points more for legs than arms from LI to HI (p > 0.05) and regarding sub-technique, 14.7% points more G3 on behalf of G2 was employed on the steepest uphill during HI (p < 0.05). Within all sub-techniques, cycle length increased two to three times more than cycle rate from LI to HI in the same terrains, while the corresponding poling time decreased more than ski contact time (all p > 0.05). In sum, both LI and HI cross-country (XC) skiing on varying terrain induce large terrain-dependent physiological and biomechanical fluctuations, similar to the patterns found during XC skiing competitions. The primary differences between training intensities were the time-dependent increase in HR, reduced relative oxygen saturation in the legs compared to the arms, and greater use of G3 on steep uphill terrain during HI training, whereas sub-technique selection, cycle rate, and pole vs. ski power distribution were similar across intensities on flat and moderately uphill terrain.
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Affiliation(s)
- Trine M Seeberg
- Department of Neuromedicine and Movement Science, Centre for Elite Sports Research, Norwegian University of Science and Technology, Trondheim, Norway.,Smart Sensor System, SINTEF DIGITAL, SINTEF AS, Oslo, Norway
| | - Jan Kocbach
- Department of Neuromedicine and Movement Science, Centre for Elite Sports Research, Norwegian University of Science and Technology, Trondheim, Norway
| | - Jørgen Danielsen
- Department of Neuromedicine and Movement Science, Centre for Elite Sports Research, Norwegian University of Science and Technology, Trondheim, Norway
| | - Dionne A Noordhof
- Department of Neuromedicine and Movement Science, Centre for Elite Sports Research, Norwegian University of Science and Technology, Trondheim, Norway
| | - Knut Skovereng
- Department of Neuromedicine and Movement Science, Centre for Elite Sports Research, Norwegian University of Science and Technology, Trondheim, Norway
| | - Frédéric Meyer
- Digital Signal Processing Group, Department of Informatics, University of Oslo, Oslo, Norway
| | - Øyvind Sandbakk
- Department of Neuromedicine and Movement Science, Centre for Elite Sports Research, Norwegian University of Science and Technology, Trondheim, Norway
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Neuromuscular Activity during Cycling Performance in Hot/Dry and Hot/Humid Conditions. Life (Basel) 2021; 11:life11111149. [PMID: 34833025 PMCID: PMC8623245 DOI: 10.3390/life11111149] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/20/2021] [Accepted: 10/20/2021] [Indexed: 11/26/2022] Open
Abstract
To determine the relationships between limiting factors and neuromuscular activity during a self-paced 20-km cycling time trial and evaluate the effect of environmental conditions on fatigue indices. Methods: Ten endurance-trained and heat-acclimated athletes performed in three conditions (ambient temperature, relative humidity): HUMID (30 °C, 90%), DRY (35 °C, 46%) and NEUTRAL (22 °C, 55%). Voluntary muscular contractions and electromagnetic stimulations were recorded before and after the time trials to assess fatigue. The data on performance, temperature, heat storage, electromyogram, heart rate and rating of perceived exertion data were analyzed. Results: Performance was impaired in DRY and HUMID compared with NEUTRAL environment (p < 0.05). The force developed by the vastus lateral muscle during stimulation of the femoral nerve remained unchanged across conditions. The percentage of integrated electromyogram activity, normalized by the value attained during the pre-trial maximal voluntary contraction, decreased significantly throughout the trial only in HUMID condition (p < 0.01). Neuromuscular activity in peripheral skeletal muscle started to fall from the 11th km in HUMID and the 15th km in DRY condition, although core temperature did not reach critical values. Conclusions: These alterations suggest that afferences from core/skin temperature regulate the central neural motor drive, reducing the active muscle recruited during prolonged exercise in the heat in order to prevent the system from hyperthermia.
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Miyazawa T, Mizutani M, Sheahan JP, Ichikawa D. Intermittent face cooling reduces perceived exertion during exercise in a hot environment. J Physiol Anthropol 2021; 40:12. [PMID: 34488878 PMCID: PMC8420073 DOI: 10.1186/s40101-021-00262-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 08/23/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Facial cooling (FC) is effective in improving endurance exercise performance in hot environments. In this study, we evaluated the impact of intermittent short-lasting FC on the ratings of perceived exertion (RPE) during exercise. METHODS Ten healthy men performed 40 continuous minutes of ergometric cycle exercise at 65% of the peak heart rate in a climatic chamber controlled at an ambient temperature of 35 °C and a relative humidity of 50%. In the control (CONT) trial, the participants performed the exercise without FC. In two cooling trials, each participant underwent 10 s of FC at 2- (FC2) and 4-min (FC4) intervals while continuing to exercise. FC was achieved by applying two soft-gel packs (cooled to 0 °C) directly and bilaterally on the forehead, eyes, and cheeks. In another cooling trial, 10 s of FC was performed at 2-min intervals using two soft-gel packs cooled to 20 °C (FC2-20). RESULTS The RPE values in the FC4 trial were significantly lower than those in the CONT trial at 20 min (FC4, 11.6 ± 2.2 points; CONT, 14.2 ± 1.3 points; P < 0.01). Further, significant differences in the RPE values were observed between the FC4 and CONT trials at 5-15 min and 25-40 min (P < 0.05). RPE values were also significantly lower in the FC2 trial than in the CONT trial (5-40 min). Although the RPE values in the FC2-20 trial were significantly lower (5-10 min; 15-20 min) than those in the CONT trial, there were no significant differences in the RPE between the FC2-20 and CONT trials at 25-40 min. At 35 min, the RPE values were significantly higher in the FC2-20 trial than in the FC2 trial (P < 0.05). CONCLUSION Intermittent short-lasting FC was associated with a decrease in RPE, with shorter intervals and lower temperatures eliciting greater attenuation of increase in the RPE.
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Affiliation(s)
- Taiki Miyazawa
- Department of Health and Sports Science, Faculty of Wellness, Shigakkan University, Obu, Japan.
| | - Mirai Mizutani
- Department of Physical Education, Shigakkan University Junior College, Obu, Japan
| | | | - Daisuke Ichikawa
- Department of Biomedical Engineering, Toyo University, Kawagoe, Japan
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17
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Chabert C, Collado A, Hue O. Temperate Air Breathing Increases Cycling Performance in Hot and Humid Climate Environment. Life (Basel) 2021; 11:life11090911. [PMID: 34575060 PMCID: PMC8465945 DOI: 10.3390/life11090911] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/30/2021] [Accepted: 07/30/2021] [Indexed: 12/02/2022] Open
Abstract
Practicing physical activity in a hot and humid climate (HHC) is becoming increasingly common due to anthropogenic climate change and the growing number of international sports events held in warm countries. The aim of this study was to understand the physiological and psychological effects of breathing two air temperatures during cycling exercise in HHC. Ten male athletes performed two sessions of exercise in HHC (T°: 32.0 ± 0.5 °C, relative humidity: 78.6 ± 0.7%) during which they breathed hot air (HA, 33.2 ± 0.06 °C) or temperate air (TA, 22.6 ± 0.1 °C). Each session was composed of 30 min of pre-fatigue cycling at constant intensity, followed by a 10 min self-regulated performance. During pre-fatigue, TA induced a better feeling score and a lower rating of perceived effort (respectively, +0.9 ± 0.2, p < 0.05; 1.13 ± 0.21; p < 0.05) with no changes in physiological parameters. During performance, oxygen consumption and mechanical workload were increased by TA (respectively, +0.23 ± 0.1 L min−1, p < 0.05 and +19.2 ± 6.1 W, p < 0.01), whereas no significant differences were observed for psychological parameters. Reducing the breathed air temperature decreased the discomfort induced by HHC during exercise and increased the performance capacity during self-regulated exercise. Thus, breathed air temperature perception is linked to the hardship of training sessions and directly contributes to the performance decrease in HHC.
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18
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de Korte JQ, Bongers CCWG, Hopman MTE, Eijsvogels TMH. Exercise Performance and Thermoregulatory Responses of Elite Athletes Exercising in the Heat: Outcomes of the Thermo Tokyo Study. Sports Med 2021; 51:2423-2436. [PMID: 34396493 PMCID: PMC8514392 DOI: 10.1007/s40279-021-01530-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/29/2021] [Indexed: 11/30/2022]
Abstract
Objective We examined the impact of simulated Tokyo 2020 environmental condition on exercise performance, thermoregulatory responses and thermal perception among Dutch elite athletes. Methods 105 elite athletes from different sport disciplines performed two exercise tests in simulated control (15.9 ± 1.2 °C, relative humidity (RH) 55 ± 6%) and Tokyo (31.6 ± 1.0 °C, RH 74 ± 5%) environmental conditions. Exercise tests consisted of a 20-min warm-up (70% HRmax), followed by an incremental phase until volitional exhaustion (5% workload increase every 3 min). Gastrointestinal temperature (Tgi), heart rate, exercise performance and thermal perception were measured. Results Time to exhaustion was 16 ± 8 min shorter in the Tokyo versus the control condition (− 26 ± 11%, whereas peak power output decreased with 0.5 ± 0.3 W/kg (16 ± 7%). Greater exercise-induced increases in Tgi (1.8 ± 0.6 °C vs. 1.5 ± 0.5 °C, p < 0.001) and higher peak Tgi (38.9 ± 0.6 °C vs. 38.7 ± 0.4 °C, p < 0.001) were found in the Tokyo versus control condition. Large interindividual variations in exercise-induced increase in Tgi (range 0.7–3.5 °C) and peak Tgi (range 37.6–40.4 °C) were found in the Tokyo condition, with greater Tgi responses in endurance versus mixed- and skill-trained athletes. Peak thermal sensation and thermal comfort scores deteriorated in the Tokyo condition, with aggravated responses for power versus endurance- and mixed-trained athletes. Conclusion Large performance losses and Tgi increases were found among elite athletes exercising in simulated Tokyo conditions, with a substantial interindividual variation and significantly different responses across sport disciplines. These findings highlight the importance of an individual approach to optimally prepare athletes for safe and maximal exercise performance during the Tokyo Olympics. Supplementary Information The online version contains supplementary material available at 10.1007/s40279-021-01530-w.
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Affiliation(s)
- Johannus Q de Korte
- Department of Physiology (392), Radboud University Medical Centre, Radboud Institute for Health Sciences, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Coen C W G Bongers
- Department of Physiology (392), Radboud University Medical Centre, Radboud Institute for Health Sciences, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Maria T E Hopman
- Department of Physiology (392), Radboud University Medical Centre, Radboud Institute for Health Sciences, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Thijs M H Eijsvogels
- Department of Physiology (392), Radboud University Medical Centre, Radboud Institute for Health Sciences, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.
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Noboa K, Keller J, Hergenrader K, Housh T, Anders JP, Neltner T, Schmidt R, Johnson G. Men Exhibit Greater Pain Pressure Thresholds and Times to Task Failure but Not Performance Fatigability Following Self-Paced Exercise. Percept Mot Skills 2021; 128:2326-2345. [PMID: 34313524 DOI: 10.1177/00315125211035028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The purpose of the current study was to determine if, and to what extent, sex differences in performance fatigability after a sustained, bilateral leg extension, anchored to a moderate rating of perceived exertion (RPE), could be attributed to muscle size, muscular strength, or pain pressure threshold (PPT) in young, healthy adults. Thirty adults (men: n = 15, women: n = 15) volunteered to complete a sustained leg extension task anchored to RPE = 5 (10-point OMNI scale) as well as pretest and posttest maximal voluntary isometric contraction (MVIC) trials. The fatigue-induced decline in MVIC force was defined as performance fatigability. We used muscle cross-sectional area (mCSA) to quantify muscle size and a dolorimeter to assess PPT. The sustained task induced fatigue such that both men and women exhibited significant (p < 0.05) decreases in MVIC force from pretest to posttest (M = 113.3, SD =24.2 kg vs. M = 98.3, SD = 23.1 kg and M = 73.1, SD =14.5 kg vs. M = 64.1, SD = 16.2 kg, respectively), with no significant sex differences in performance fatigability (grand M = 12.6, SD =10.6%). Men, however, exhibited significantly (p < 0.05) longer time to task failure (TTF) than women (M = 166.1, SD =83.0 seconds vs. M = 94.6, SD =41.7) as well as greater PPT (M = 5.9, SD = 2.2 kg vs. M = 3.4, SD =1.1 kg). The only significant predictor of performance fatigability was PPT. In conclusion, differences in PPT, at least in part, mediate variations in TTF during self-paced exercise anchored to a specific RPE and resulting in performance fatigability.
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Affiliation(s)
- Karina Noboa
- Performance and Physique Enhancement Laboratory, Department of Educational and Psychological Studies, College of Education, University of South Florida, Tampa, Florida, United States
| | - Joshua Keller
- Department of Health, Kinesiology, and Sport, College of Education and Professional Studies, University of South Alabama, Mobile, United States
| | - Kipp Hergenrader
- Human Performance Laboratory, Department of Nutrition and Health Sciences, College of Education, University of Nebraska - Lincoln, Lincoln, United States
| | - Terry Housh
- Human Performance Laboratory, Department of Nutrition and Health Sciences, College of Education, University of Nebraska - Lincoln, Lincoln, United States
| | - John Paul Anders
- Human Performance Laboratory, Department of Nutrition and Health Sciences, College of Education, University of Nebraska - Lincoln, Lincoln, United States
| | - Tyler Neltner
- Human Performance Laboratory, Department of Nutrition and Health Sciences, College of Education, University of Nebraska - Lincoln, Lincoln, United States
| | - Richard Schmidt
- Human Performance Laboratory, Department of Nutrition and Health Sciences, College of Education, University of Nebraska - Lincoln, Lincoln, United States
| | - Glen Johnson
- Human Performance Laboratory, Department of Nutrition and Health Sciences, College of Education, University of Nebraska - Lincoln, Lincoln, United States
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20
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Relf RL, Lee BJ, Eichhorn G, Flint MS, Beale L, Maxwell N. Thermoregulation is not impaired in breast cancer survivors during moderate-intensity exercise performed in warm and hot environments. Physiol Rep 2021; 9:e14968. [PMID: 34291605 PMCID: PMC8295682 DOI: 10.14814/phy2.14968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 06/17/2021] [Accepted: 06/22/2021] [Indexed: 11/30/2022] Open
Abstract
This study aimed to assess how female breast cancer survivors (BCS) respond physiologically, hematologically, and perceptually to exercise under heat stress compared to females with no history of breast cancer (CON). Twenty-one females (9 BCS and 12 CON [age; 54 ± 7 years, stature; 167 ± 6 cm, body mass; 68.1 ± 7.62 kg, and body fat; 30.9 ± 3.8%]) completed a warm (25℃, 50% relative humidity, RH) and hot (35℃, 50%RH) trial in a repeated-measures crossover design. Trials consisted of 30 min of rest, 30 min of walking at 4 metabolic equivalents, and a 6-minute walk test (6MWT). Physiological measurements (core temperature (Tre ), skin temperature (Tskin ), heart rate (HR), and sweat analysis) and perceptual rating scales (ratings of perceived exertion, thermal sensation [whole body and localized], and thermal comfort) were taken at 5- and 10-min intervals throughout, respectively. Venous blood samples were taken before and after to assess; IL-6, IL-10, CRP, IFN-γ, and TGF-β1 . All physiological markers were higher during the 35 versus 25℃ trial; Tre (~0.25℃, p = 0.002), Tskin (~3.8℃, p < 0.001), HR (~12 beats·min-1 , p = 0.023), and whole-body sweat rate (~0.4 L·hr-1 , p < 0.001), with no difference observed between groups in either condition (p > 0.05). Both groups covered a greater 6MWT distance in 25 versus 35℃ (by ~200 m; p = 0.003). Nevertheless, the control group covered more distance than BCS, regardless of environmental temperature (by ~400 m, p = 0.03). Thermoregulation was not disadvantaged in BCS compared to controls during moderate-intensity exercise under heat stress. However, self-paced exercise performance was reduced for BCS regardless of environmental temperature.
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Affiliation(s)
- Rebecca L. Relf
- Environmental Extremes LaboratoryUniversity of BrightonEastbourneUK
| | - Ben J. Lee
- Occupational and Environmental Physiology GroupCoventry UniversityCoventryUK
| | - Gregor Eichhorn
- Environmental Extremes LaboratoryUniversity of BrightonEastbourneUK
| | - Melanie S. Flint
- Cancer Stress LaboratoryUniversity of BrightonMoulsecoombUK
- Centre for Stress and Age‐Related DiseaseBrightonEast SussexUK
| | - Louisa Beale
- Environmental Extremes LaboratoryUniversity of BrightonEastbourneUK
| | - Neil Maxwell
- Environmental Extremes LaboratoryUniversity of BrightonEastbourneUK
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21
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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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22
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Périard JD, Eijsvogels TMH, Daanen HAM. Exercise under heat stress: thermoregulation, hydration, performance implications, and mitigation strategies. Physiol Rev 2021; 101:1873-1979. [PMID: 33829868 DOI: 10.1152/physrev.00038.2020] [Citation(s) in RCA: 148] [Impact Index Per Article: 49.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A rise in body core temperature and loss of body water via sweating are natural consequences of prolonged exercise in the heat. This review provides a comprehensive and integrative overview of how the human body responds to exercise under heat stress and the countermeasures that can be adopted to enhance aerobic performance under such environmental conditions. The fundamental concepts and physiological processes associated with thermoregulation and fluid balance are initially described, followed by a summary of methods to determine thermal strain and hydration status. An outline is provided on how exercise-heat stress disrupts these homeostatic processes, leading to hyperthermia, hypohydration, sodium disturbances, and in some cases exertional heat illness. The impact of heat stress on human performance is also examined, including the underlying physiological mechanisms that mediate the impairment of exercise performance. Similarly, the influence of hydration status on performance in the heat and how systemic and peripheral hemodynamic adjustments contribute to fatigue development is elucidated. This review also discusses strategies to mitigate the effects of hyperthermia and hypohydration on exercise performance in the heat by examining the benefits of heat acclimation, cooling strategies, and hyperhydration. Finally, contemporary controversies are summarized and future research directions are provided.
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Affiliation(s)
- Julien D Périard
- University of Canberra Research Institute for Sport and Exercise, Bruce, Australia
| | - Thijs M H Eijsvogels
- Department of Physiology, Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Hein A M Daanen
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
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Davey SL, Downie V, Griggs K, Havenith G. The physiological strain index does not reliably identify individuals at risk of reaching a thermal tolerance limit. Eur J Appl Physiol 2021; 121:1701-1713. [PMID: 33677693 PMCID: PMC8144153 DOI: 10.1007/s00421-021-04642-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 02/13/2021] [Indexed: 01/09/2023]
Abstract
PURPOSE The physiological strain index (PSI) was developed to assess individuals' heat strain, yet evidence supporting its use to identify individuals at potential risk of reaching a thermal tolerance limit (TTL) is limited. The aim of this study was to assess whether PSI can identify individuals at risk of reaching a TTL. METHODS Fifteen females and 21 males undertook a total of 136 trials, each consisting of two 40-60 minute periods of treadmill walking separated by ~ 15 minutes rest, wearing permeable or impermeable clothing, in a range of climatic conditions. Heart rate (HR), skin temperature (Tsk), rectal temperature (Tre), temperature sensation (TS) and thermal comfort (TC) were measured throughout. Various forms of the PSI-index were assessed including the original PSI, PSIfixed, adaptive-PSI (aPSI) and a version comprised of a measure of heat storage (PSIHS). Final physiological and PSI values and their rate of change (ROC) over a trial and in the last 10 minutes of a trial were compared between trials completed (C, 101 trials) and those terminated prematurely (TTL, 35 trials). RESULTS Final PSIoriginal, PSIfixed, aPSI, PSIHS did not differ between TTL and C (p > 0.05). However, differences between TTL and C occurred in final Tsk, Tre-Tsk, TS, TC and ROC in PSIfixed, Tre, Tsk and HR (p < 0.05). CONCLUSION These results suggest the PSI, in the various forms, does not reliably identify individuals at imminent risk of reaching their TTL and its validity as a physiological safety index is therefore questionable. However, a physiological-perceptual strain index may provide a more valid measure.
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Affiliation(s)
- Sarah L Davey
- Environmental Ergonomics Research Centre, Loughborough Design School, Loughborough University, Loughborough, LE11 3TU, UK.,Department of Health and Life Sciences, Coventry University, Oxford, UK
| | - Victoria Downie
- Environmental Ergonomics Research Centre, Loughborough Design School, Loughborough University, Loughborough, LE11 3TU, UK.,English Institute of Sport, Manchester, UK
| | - Katy Griggs
- Environmental Ergonomics Research Centre, Loughborough Design School, Loughborough University, Loughborough, LE11 3TU, UK.,Department of Engineering, School of Science and Technology, Nottingham Trent University, Nottingham, UK
| | - George Havenith
- Environmental Ergonomics Research Centre, Loughborough Design School, Loughborough University, Loughborough, LE11 3TU, UK.
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Coudevylle GR, Sinnapah S, Collado A, Fenouillet F, Hue O, Parrat M, Robin N. If Motivation Was a Key Factor in Aerobic Performance in Tropical Climate? Front Psychol 2021; 11:619198. [PMID: 33597904 PMCID: PMC7882517 DOI: 10.3389/fpsyg.2020.619198] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 12/24/2020] [Indexed: 11/28/2022] Open
Abstract
This mini review examines the impact of tropical climate (TC) on motivational factors during aerobic performance and proposes the tracks of an integrative theoretical model to better understand the direct and indirect motivational mechanisms that can operate on athletic performances. TC is detrimental for aerobic performance and, although it clearly induces physiological constraints, these do not seem to be the only factors that explain the performance decline. Indeed, TC performance researchers have developed a theory of anticipation, which suggests that the brain commands a reduction in effort to protect the body from probable harm and heatstroke risk. The objective of this mini review is thus to examine the possibility that motivation may be a key factor in TC performance. The main psychological impacts of TC on aerobic performance are reviewed and an integrative theoretical model is presented that may help to better understand the mechanisms of motivation.
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Affiliation(s)
| | - Stéphane Sinnapah
- Laboratory ACTES (EA 3596), University of the French Antilles, Pointe-à-Pitre, France
| | - Aurélie Collado
- Laboratory ACTES (EA 3596), University of the French Antilles, Pointe-à-Pitre, France
| | - Fabien Fenouillet
- Laboratoire Interdisciplinaire en Neurosciences, Physiologie et Psychologie: Apprentissages, Activité Physique, Santé (LINP2-2APS), University of Paris Nanterre, Nanterre, France
| | - Olivier Hue
- Laboratory ACTES (EA 3596), University of the French Antilles, Pointe-à-Pitre, France
| | - Matthieu Parrat
- Laboratory ACTES (EA 3596), University of the French Antilles, Pointe-à-Pitre, France
| | - Nicolas Robin
- Laboratory ACTES (EA 3596), University of the French Antilles, Pointe-à-Pitre, France
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Barenie MJ, Domenick JT, Bennett JE, Schweitzer GG, Shetty P, Weiss EP. Short Term High-Repetition Back Squat Protocol Does Not Improve 5-km Run Performance. INTERNATIONAL JOURNAL OF EXERCISE SCIENCE 2020; 13:1770-1782. [PMID: 33414887 PMCID: PMC7745891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The purpose of this study was to evaluate the hypothesis that a novel high-repetition, low-resistance back squat training protocol, designed to stimulate high-intensity interval training, improves 5-km run performance. Fifteen runners [4 male, 11 female; 150 + minutes of endurance exercise/week; age = 22.7 ± 2.0 y; 21.5 ± 2.2 kg/m2 BMI] in this single-group test-retest design completed two weeks of back squats consisting of three sets of 15-24 repetitions at 60% of estimated one-repetition max (1RM), three times per week (1-2 days of rest between sessions). Outcome tests included a 5-km outdoor timed run, laboratory indirect calorimetry to quantify substrate oxidation rates during steady-state submaximal exercise (60% and 70% heart rate max (HRmax)), and estimated 1RM for back squats. Back squat estimated 1RM increased by 20% (58.3 ± 18.5 to 70.2 ± 16.7 kg, P < 0.001). However, 5-km run times due to the back squat protocol did not significantly change (Pre-Squats: 23.9 ± 5.0 vs. Post-Squats: 23.7 ± 4.3 minutes, P = 0.71). Likewise, the squat training program did not significantly alter carbohydrate or lipid oxidation rates during steady-state submaximal exercise at 60% or 70% of HRmax (P values ranged from 0.36 - 0.99). Short term high-repetition back squat training does not appear to impact 5-km run performance or substrate utilization during submaximal exercise.
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Affiliation(s)
- Matthew J Barenie
- Department of Nutrition and Dietetics, Saint Louis University, St. Louis, MO, USA
- Human Performance and Exercise Biochemistry Laboratory, Department of Kinesiology, Indiana University, Bloomington, IN, USA
| | - Jordan T Domenick
- Department of Nutrition and Dietetics, Saint Louis University, St. Louis, MO, USA
| | - Jason E Bennett
- Department of Physical Therapy, Carroll University, Waukesha, WI, USA
| | - George G Schweitzer
- Deparment of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Paulina Shetty
- Science Department, Johnson County Community College, Overland Park, KS, USA
| | - Edward P Weiss
- Department of Nutrition and Dietetics, Saint Louis University, St. Louis, MO, USA
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Parton AJ, Waldron M, Clifford T, Jeffries O. Thermo-behavioural responses to orally applied l-menthol exhibit sex-specific differences during exercise in a hot environment. Physiol Behav 2020; 229:113250. [PMID: 33220326 DOI: 10.1016/j.physbeh.2020.113250] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 09/29/2020] [Accepted: 11/16/2020] [Indexed: 10/23/2022]
Abstract
AIMS This study investigated the efficacy of l-menthol mouth-rinsing on thermal sensation and perceived effort in females and males, using a fixed-rating of perceived exertion (RPE) exercise protocol in a hot environment. METHODS Twenty-two participants (eleven females, eleven males) completed two trials using a fixed-RPE protocol at an exercise intensity between 'hard' and 'very hard', equating to 16 on the RPE scale at ~35 °C. Participants adjusted power output to maintain RPE-16. In a randomised, double-blind, crossover design, l-menthol or a control mouthwash was administered at an orally neutral temperature (~32 °C) prior to exercise and at 10 min intervals thereafter. Measures of mechanical power output, core temperature, heart rate, perception of thermal sensation and thermal comfort, and whole-body sweat loss are reported. RESULTS Thermal sensation was lowered by l-menthol in both sexes (P < 0.05), however during exercise this was only maintained for 40% of the trial duration in females. Thermal comfort did not differ between conditions (P > 0.05). No differences in exercise duration were observed compared to control, despite a ~4% and ~6% increase in male and females respectively. Power output increased by ~6.5% males (P = 0.039) with no difference in females ~2.2% (P = 0.475), compared to control. Core temperature, heart rate and whole-body sweat loss was not different between condition or sex. CONCLUSIONS l-menthol lowered perceptual measures of thermal sensation in females, but did not attenuate a greater rate of rise in thermal sensitivity when exercising in a hot environment, compared to males. Males appeared to adopt a higher risk strategy by increasing power output following l-menthol administration in contrast to a more conservative pacing strategy in females. Therefore, there appear to be sex-specific differences in l-menthol's non-thermal cooling properties and subsequent effects on thermo-behavioural adjustments in work-load when exercising in a hot environment.
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Affiliation(s)
- Abbie Jayne Parton
- School of Biomedical, Nutritional and Sport Sciences, Newcastle University, Newcastle Upon Tyne, United Kingdom
| | - Mark Waldron
- College of Engineering, Swansea University, Swansea, United Kingdom; School of Science and Technology, University of New England, Armidale, NSW, Australia
| | - Tom Clifford
- School of Sport, Health and Exercise Sciences, Loughborough University, Loughborough, United Kingdom
| | - Owen Jeffries
- School of Biomedical, Nutritional and Sport Sciences, Newcastle University, Newcastle Upon Tyne, United Kingdom.
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Rodrigues Júnior JFC, Mckenna Z, Amorim FT, Da Costa Sena AF, Mendes TT, Veneroso CE, Torres Cabido CE, Sevilio De Oliveira Júnior MN. Thermoregulatory and metabolic responses to a half-marathon run in hot, humid conditions. J Therm Biol 2020; 93:102734. [PMID: 33077145 DOI: 10.1016/j.jtherbio.2020.102734] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 09/11/2020] [Accepted: 09/13/2020] [Indexed: 10/23/2022]
Abstract
This study describes the thermoregulatory and metabolic responses during a simulated half-marathon (21 km) run performed outdoors in a hot, humid environment. Ten male runners were recruited for the study, The run was carried out individually under solar radiation on a predetermined path in the following environmental conditions (ambient temperature: 27.96 ± 1.70 °C, globe temperature: 28.52 ± 2.51 °C, relative humidity: 76.88 ± 7.49%, wet bulb globe temperature: 25.80 ± 1.18 °C). Core temperature, skin temperature, head temperature, heat storage, heart rate, expired gases, rating of perceived exertion, and speed were measured or calculated before the start, every 3 km, and immediately following the run. Comparisons were made for each dependent variable using one-way repeated measures analysis of variance tests, and a Bonferroni test. Average run time and pace were 101:00 ± 9:52 min and 4:48 ± 00:16 min km-1, respectively. Participants significantly reduced their running speed, oxygen consumption, and heat storage at 9 km (p < 0.05). While core temperature was significantly increased at 6 km (p < 0.05) before plateauing for the remainder of the run. The key finding was that most of the runners reduced their pace when a Tcore of 39 °C was reached which occurred between 6 and 9 km of the run, yet runners were able to increase their speed demonstrating an "end-spurt" near the end of the run.
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Affiliation(s)
| | - Zachary Mckenna
- Department of Health, Exercise and Sports Sciences, University of New Mexico, Albuquerque, NM, USA.
| | - Fabiano Trigueiro Amorim
- Department of Health, Exercise and Sports Sciences, University of New Mexico, Albuquerque, NM, USA
| | - Alyson Felipe Da Costa Sena
- Graduate Program in Physical Education, Department of Physical Education, Federal University of Maranhão, São Luis, MA, Brazil
| | - Thiago Teixeira Mendes
- Graduate Program in Physical Education, Department of Physical Education, Federal University of Maranhão, São Luis, MA, Brazil
| | - Christiano Eduardo Veneroso
- Graduate Program in Physical Education, Department of Physical Education, Federal University of Maranhão, São Luis, MA, Brazil
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Self-Regulated Force and Neuromuscular Responses During Fatiguing Isometric Leg Extensions Anchored to a Rating of Perceived Exertion. Appl Psychophysiol Biofeedback 2020; 44:343-350. [PMID: 31494754 DOI: 10.1007/s10484-019-09450-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The purpose of the study was to examine the fatigue-related patterns of responses for electromyography (EMG), mechanomyography (MMG), and force during a sustained isometric muscle action anchored to RPE = 5. Ten men (22.9 ± 2.0 year) performed maximal voluntary isometric contractions (MVIC) prior to and following an isometric leg extension muscle action, which was sustained for a maximal time-limit of 5 min or until it could not be maintained at RPE = 5 (actual time-limit). EMG amplitude (AMP), EMG mean power-frequency (MPF), MMG AMP, MMG MPF, and force values were determined every 5% of the actual time-limit. Regression analyses were used to examine the neuromuscular parameters and force responses, and a t test was used to examine MVIC. The pretest MVIC (62.4 ± 14.3 kg) was significantly (p < 0.001; d = 1.07) greater than posttest (47.9 ± 12.8 kg). The percent decline in force during the sustained isometric muscle action was 47.5 ± 19.6%, and there was a significant, negative force versus time relationship (p < 0.001; R = - 0.980). There was a significant, negative EMG AMP versus time relationship (p < 0.001; R = -0.789), but no significant (p > 0.05) relationships for EMG MPF, MMG AMP, or MMG MPF versus time. The findings indicated that it was necessary to reduce force and EMG AMP to maintain RPE = 5. We hypothesize that the maintenance of RPE = 5 was initially accomplished by an anticipatory feedforward mechanism and then continuous integrations of afferent feedback, which resulted in reductions of EMG AMP and force, due to reductions in neural drive, to attenuate the impact of metabolic byproducts.
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29
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Millyard A, Layden JD, Pyne DB, Edwards AM, Bloxham SR. Impairments to Thermoregulation in the Elderly During Heat Exposure Events. Gerontol Geriatr Med 2020; 6:2333721420932432. [PMID: 32596421 PMCID: PMC7297481 DOI: 10.1177/2333721420932432] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 05/06/2020] [Accepted: 05/14/2020] [Indexed: 12/11/2022] Open
Abstract
Heat waves represent a public health risk to elderly people, and typically result in an increased rate of hospital admissions and deaths. Studies of thermoregulation in this cohort have generally focused on single elements such as sweating capacity. Sweating capacity and skin blood flow reduce with age, reducing ability to dissipate heat. Perception of effort during heat exposure is emerging as an area that needs further investigation as the elderly appear to lack the ability to adequately perceive increased physiological strain during heat exposure. The role of the gut and endotoxemia in heat stress has received attention in young adults, while the elderly population has been neglected. This shortcoming offers another potential avenue for identifying effective integrated health interventions to reduce heat illnesses. Increasing numbers of elderly individuals in populations worldwide are likely to increase the incidence of heat wave-induced deaths if adequate interventions are not developed, evaluated, and implemented. In this narrative-style review we identify and discuss health-related interventions for reducing the impact of heat illnesses in the elderly.
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Affiliation(s)
| | | | - David B Pyne
- University of Canberra, Australian Capital Territory, Australia
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30
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Keller JL, Housh TJ, Hill EC, Smith CM, Schmidt RJ, Johnson GO. Sex-Related Differences in Performance Fatigability Independent of Blood Flow Following a Sustained Muscle Action at a Low Perceptual Intensity. ACTA ACUST UNITED AC 2020. [DOI: 10.1007/s42978-020-00052-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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31
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Douzi W, Dupuy O, Theurot D, Smolander J, Dugué B. Per-Cooling (Using Cooling Systems during Physical Exercise) Enhances Physical and Cognitive Performances in Hot Environments. A Narrative Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:E1031. [PMID: 32041228 PMCID: PMC7036802 DOI: 10.3390/ijerph17031031] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 01/25/2020] [Accepted: 01/29/2020] [Indexed: 12/19/2022]
Abstract
There are many important sport events that are organized in environments with a very hot ambient temperature (Summer Olympics, FIFA World Cup, Tour de France, etc.) and in hot locations (e.g., Qatar). Additionally, in the context of global warming and heat wave periods, athletes are often subjected to hot ambient temperatures. It is known that exercising in the heat induces disturbances that may provoke premature fatigue and negatively affects overall performance in both endurance and high intensity exercises. Deterioration in several cognitive functions may also occur, and individuals may be at risk for heat illnesses. To train, perform, work and recover and in a safe and effective way, cooling strategies have been proposed and have been routinely applied before, during and after exercise. However, there is a limited understanding of the influences of per-cooling on performance, and it is the subject of the present review. This work examines the influences of per-cooling of different areas of the body on performance in terms of intense short-term exercises ("anaerobic" exercises), endurance exercises ("aerobic" exercises), and cognitive functioning and provides detailed strategies that can be applied when individuals train and/or perform in high ambient temperatures.
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Affiliation(s)
| | | | | | | | - Benoit Dugué
- University of Poitiers, Laboratoire Mobilité Vieillissement Exercice (MOVE)-EA6314, Faculty of Sport Sciences, 8 Allée Jean Monnet, 86000 Poitiers, France; (W.D.); (O.D.); (D.T.); (J.S.)
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32
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Ely BR, Ely MR. Running in the Heat: Performance Consequences and Strategies to Prepare for Hot-Weather Racing. Strength Cond J 2020. [DOI: 10.1519/ssc.0000000000000484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Keller JL, Housh TJ, Hill EC, Smith CM, Schmidt RJ, Johnson GO. Are There Sex-Specific Neuromuscular or Force Responses to Fatiguing Isometric Muscle Actions Anchored to a High Perceptual Intensity? J Strength Cond Res 2019; 36:156-161. [PMID: 31860532 DOI: 10.1519/jsc.0000000000003394] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Keller, JL, Housh, TJ, Hill, EC, Smith, CM, Schmidt, RJ, and Johnson, GO. Are there sex-specific neuromuscular or force responses to fatiguing isometric muscle actions anchored to a high perceptual intensity? J Strength Cond Res XX(X): 000-000, 2019-The purpose of this study was to use the ratings of perceived exertion (RPE) clamp model to examine sex-specific changes in neuromuscular responses and force after a sustained isometric leg extension muscle action anchored to RPE = 8. Twenty adults (10 men and 10 women) performed sustained, isometric leg extension muscle actions at RPE = 8. Electromyographic (EMG) and mechanomyographic signals were recorded from the dominant leg. Neuromuscular and force values resulting from the sustained muscle action were normalized to pretest maximal voluntary isometric contractions (MVICs). The level of significance set for the study was p ≤ 0.05. The pretest MVIC was significantly (p < 0.001) greater (averaged across sex) than posttest MVIC force (55.5 ± 10.0 vs. 47.6 ± 11.1 kg). There was a significant (p < 0.01) decrease from pretest (95.4 ± 7.7 Hz) to posttest (76.2 ± 5.9 Hz) in EMG mean power frequency (MPF) for the men. The normalized force (averaged across sex) decreased significantly (p < 0.001) from the initial timepoint (57.1 ± 16.4%) to the final timepoint (44.3 ± 15.7%) of the sustained muscle action. Normalized EMG MPF (averaged across sex) decreased significantly (p = 0.001) from the initial timepoint (96.4 ± 17.5%) to final timepoint (87.8 ± 18.1%). The men and women exhibited similar fatigue-induced changes in force and neuromuscular parameters; therefore, these findings did not indicate different sex-specific responses after the fatiguing task anchored to a high perception of exertion. The force corresponding to RPE = 8 did not match the anticipated value; so, RPE and percentages of MVIC cannot be used interchangeably, and sustained isometric muscle actions anchored to RPE may elicit unique neuromuscular adaptations.
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Affiliation(s)
- Joshua L Keller
- Human Performance Laboratory, Department of Nutrition and Health Sciences, College of Education and Human Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Terry J Housh
- Human Performance Laboratory, Department of Nutrition and Health Sciences, College of Education and Human Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Ethan C Hill
- Division of Kinesiology, School of Kinesiology and Physical Therapy, University of Central Florida, Orlando, Florida
| | - Cory M Smith
- Department of Kinesiology, College of Health Sciences, University of Texas at El Paso, El Paso, Texas 79968
| | - Richard J Schmidt
- Human Performance Laboratory, Department of Nutrition and Health Sciences, College of Education and Human Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Glen O Johnson
- Human Performance Laboratory, Department of Nutrition and Health Sciences, College of Education and Human Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska
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Wood T, Bui CTL, Lubbock C, Wilson J, Jeffrey S, Lawrence M, Leung C, Mashar D, Sims N, Konings MJ, Hettinga FJ. Head-to-head competition does not affect pacing or performance in 1 km cycling time trials. J Sports Sci 2019; 38:1-5. [PMID: 31575324 DOI: 10.1080/02640414.2019.1674525] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Previous research has shown enhanced performance and altered pacing behaviour in the presence of a virtual opponent during middle-distance cycling time trials with a duration of 2 min and longer. The purpose of this study was to determine whether these effects are also present in cycling time trials of shorter duration. Twelve physically active men completed three 1-km time trials. After a familiarisation trial (FAM), participants performed two experimental conditions: one without opponent (NO) and one with a virtual opponent (OP). Repeated-measures ANOVAs were used to assess differences in pacing and performance using power output and duration (p<0.05). No differences in mean finishing times (FAM: 91.5 ± 7.7 s; NO: 91.6 ± 6.4 s; OP: 90.9 ± 4.9 s; p=0.907) or power output (FAM: 382 ± 111 W; NO: 363 ± 80 W; OP: 367 ± 67; p=0.564) were found between experimental conditions. Furthermore, no differences in pacing profiles between experimental conditions were found (p=0.199). Similarly, rate of perceived exertion did not differ between experimental conditions at any moment (p=0.831). In conclusion, unlike events of a more prolonged duration (>2 min), the presence of an opponent did not affect participants' pacing behaviour in short duration 1-km time trials.
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Affiliation(s)
- Tiffany Wood
- Department of Sport, Exercise & Rehabilitation, Northumbria University, Newcastle Upon Tyne, UK
| | - Connor Thien Long Bui
- Department of Sport, Exercise & Rehabilitation, Northumbria University, Newcastle Upon Tyne, UK
| | - Connor Lubbock
- Department of Sport, Exercise & Rehabilitation, Northumbria University, Newcastle Upon Tyne, UK
| | - Jason Wilson
- Department of Sport, Exercise & Rehabilitation, Northumbria University, Newcastle Upon Tyne, UK
| | - Scott Jeffrey
- Department of Sport, Exercise & Rehabilitation, Northumbria University, Newcastle Upon Tyne, UK
| | - Mitchell Lawrence
- Department of Sport, Exercise & Rehabilitation, Northumbria University, Newcastle Upon Tyne, UK
| | - Colleen Leung
- Department of Sport, Exercise & Rehabilitation, Northumbria University, Newcastle Upon Tyne, UK
| | - Darshit Mashar
- Department of Sport, Exercise & Rehabilitation, Northumbria University, Newcastle Upon Tyne, UK
| | - Nicholas Sims
- Department of Sport, Exercise & Rehabilitation, Northumbria University, Newcastle Upon Tyne, UK
| | - Marco J Konings
- Department of Sport, Exercise & Rehabilitation, Northumbria University, Newcastle Upon Tyne, UK
| | - Florentina J Hettinga
- Department of Sport, Exercise & Rehabilitation, Northumbria University, Newcastle Upon Tyne, UK
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35
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Levine A, Buono MJ. Rating of perceived exertion increases synergistically during prolonged exercise in a combined heat and hypoxic environment. J Therm Biol 2019; 84:99-102. [PMID: 31466796 DOI: 10.1016/j.jtherbio.2019.06.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 05/31/2019] [Accepted: 06/03/2019] [Indexed: 11/29/2022]
Abstract
The purpose of this study was to determine the cardiovascular, thermoregulatory, and perceived exertion responses during 2 h of moderate intensity exercise in a combined high heat (38 °C, 40% relative humidity) and hypoxic (15% O2) environment. Ten healthy volunteers completed 2 h of treadmill walking at 40% of maximal oxygen uptake in four different conditions, each separated by approximately 1 week: (1) control, 23 °C/20.9% O2, (2) heat, 38 °C/20.9% O2, (3) hypoxia, 23 °C/15% O2, and (4) combined heat/hypoxia, 38 °C/15% O2. Compared to the responses seen in each condition alone, heart rate (HR) and core temperature (Tcore) showed an additive increase in the combined heat and hypoxic environment after 2 h of moderate intensity exercise. The most important new finding was that the mean rating of perceived exertion (RPE) increased synergistically 3.3 units when exercising in the combined high heat and hypoxic environment, compared to 1.9 units in the heat condition alone. The results suggest that RPE is a conscious perception of effort that plays a regulatory function to ensure that the work rate remains at an intensity that can be safely sustained, rather than simply a marker of exercise intensity. Such results also support previous anecdotal reports that exercise on hot days at altitude seem unusually difficult.
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Affiliation(s)
- Ashley Levine
- School of Exercise and Nutritional Sciences, San Diego State University San Diego, CA, 92182, United States
| | - Michael J Buono
- Biology Department, San Diego State University, San Diego, CA, 92182, United States; School of Exercise and Nutritional Sciences, San Diego State University San Diego, CA, 92182, United States.
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Griggs KE, Stephenson BT, Price MJ, Goosey-Tolfrey VL. Heat-related issues and practical applications for Paralympic athletes at Tokyo 2020. Temperature (Austin) 2019; 7:37-57. [PMID: 32166104 PMCID: PMC7053936 DOI: 10.1080/23328940.2019.1617030] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 05/02/2019] [Accepted: 05/06/2019] [Indexed: 02/07/2023] Open
Abstract
International sporting competitions, including the Paralympic Games, are increasingly being held in hot and/or humid environmental conditions. Thus, a greater emphasis is being placed on preparing athletes for the potentially challenging environmental conditions of the host cities, such as the upcoming Games in Tokyo in 2020. However, evidence-based practices are limited for the impairment groups that are eligible to compete in Paralympic sport. This review aims to provide an overview of heat-related issues for Paralympic athletes alongside current recommendations to reduce thermal strain and technological advancements in the lead up to the Tokyo 2020 Paralympic Games. When competing in challenging environmental conditions, a number of factors may contribute to an athlete's predisposition to heightened thermal strain. These include the characteristics of the sport itself (type, intensity, duration, modality, and environmental conditions), the complexity and severity of the impairment and classification of the athlete. For heat vulnerable Paralympic athletes, strategies such as the implementation of cooling methods and heat acclimation can be used to combat the increase in heat strain. At an organizational level, regulations and specific heat policies should be considered for several Paralympic sports. Both the utilization of individual strategies and specific heat health policies should be employed to ensure that Paralympics athletes' health and sporting performance are not negatively affected during the competition in the heat at the Tokyo 2020 Paralympic Games.
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Affiliation(s)
- Katy E. Griggs
- Department of Engineering, School of Science and Technology, Nottingham Trent University, Nottingham, UK
| | - Ben T. Stephenson
- Loughborough Performance Centre, English Institute of Sport, Loughborough University, Loughborough, UK
- Peter Harrison Centre for Disability Sport, School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Michael J. Price
- School of Life Sciences, Centre for Sport, Exercise and Life Sciences, Coventry University, Coventry, UK
| | - Victoria L. Goosey-Tolfrey
- Peter Harrison Centre for Disability Sport, School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
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Enhancement of Exercise Capacity in the Heat With Repeated Menthol-Spray Application. Int J Sports Physiol Perform 2019; 14:644-649. [PMID: 30427234 DOI: 10.1123/ijspp.2018-0561] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Purpose: Exercise performance is impaired in the heat, and a contributing factor to this decrement is thermal discomfort. Menthol spraying of skin is one means of alleviating thermal discomfort but has yet to be shown to be ergogenic using single-spray applications. The authors examined whether repeated menthol spraying could relieve thermal discomfort, reduce perception of exertion, and improve exercise performance in hot (35°C), dry (22% relative humidity) conditions, hypothesizing that it would. Methods: A total of 8 trained cyclists completed 2 separate conditions of fixed-intensity cycling (50% maximal power output) for 45 min before a test to exhaustion (TTE; 70% maximal power output) with 100 mL of menthol spray (0.20% menthol) or control spray applied to the torso after 20 and 40 min. Perceptual (thermal sensation, thermal comfort, and rating of perceived exertion) performance (TTE duration), thermal variables (skin temperature, rectal temperature, and cardiac frequency), and sweating were measured. Data were compared using analysis of variance to .05 alpha level. Results: Menthol spray improved thermal sensation (cold sensation cf warm/hot after first spraying; P = .008) but only descriptively altered thermal comfort (comfortable cf uncomfortable; P = .173). Sweat production (994 [380] mL cf 1180 [380] mL; P = .020) and sweat rate (827 [327] mL·h-1 cf 941 [319] mL·h-1; P = .048) lowered. TTE performance improved (4.6 [1.74] cf 2.4 [1.55] min; P = .004). Menthol-spray effects diminished despite repeated applications, indicating increased contribution of visceral thermoreceptors to thermal perception. Conclusion: Repeated menthol spraying improves exercise capacity but alters thermoregulation, potentially conflicting behavioral and thermoregulatory drivers; care should be taken with its use. Carrying and deploying menthol spray would impose a logistical burden that needs consideration against performance benefit.
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Nilsson JÅ, Nord A. Testing the heat dissipation limit theory in a breeding passerine. Proc Biol Sci 2019; 285:rspb.2018.0652. [PMID: 29769365 DOI: 10.1098/rspb.2018.0652] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 04/19/2018] [Indexed: 11/12/2022] Open
Abstract
The maximum work rate of animals has recently been suggested to be determined by the rate at which excess metabolic heat generated during work can be dissipated (heat dissipation limitation (HDL) theory). As a first step towards testing this theory in wild animals, we experimentally manipulated brood size in breeding marsh tits (Poecile palustris) to change their work rate. Parents feeding nestlings generally operated at above-normal body temperatures. Body temperature in both males and females increased with maximum ambient temperature and with manipulated work rate, sometimes even exceeding 45°C, which is close to suggested lethal levels for birds. Such high body temperatures have previously only been described for birds living in hot and arid regions. Thus, reproductive effort in marsh tits may potentially be limited by the rate of heat dissipation. Females had lower body temperatures, a possible consequence of their brood patch serving as a thermal window facilitating heat dissipation. Because increasing body temperatures are connected to somatic costs, we suggest that the HDL theory may constitute a possible mediator of the trade-off between current and future reproduction. It follows that globally increasing, more stochastic, ambient temperatures may restrict the capacity for sustained work of animals in the future.
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Affiliation(s)
- Jan-Åke Nilsson
- Department of Biology, Section of Evolutionary Ecology, Lund University, Ecology Building, 223 62 Lund, Sweden
| | - Andreas Nord
- Department of Biology, Section of Evolutionary Ecology, Lund University, Ecology Building, 223 62 Lund, Sweden
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The effect of severe and moderate hypoxia on exercise at a fixed level of perceived exertion. Eur J Appl Physiol 2019; 119:1213-1224. [PMID: 30820661 PMCID: PMC6469630 DOI: 10.1007/s00421-019-04111-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Accepted: 02/21/2019] [Indexed: 02/08/2023]
Abstract
Purpose The purpose of this study was to determine the primary cues regulating perceived effort and exercise performance using a fixed-RPE protocol in severe and moderate hypoxia. Methods Eight male participants (26 ± 6 years, 76.3 ± 8.6 kg, 178.5 ± 3.6 cm, 51.4 ± 8.0 mL kg− 1 min− 1\documentclass[12pt]{minimal}
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\begin{document}$$\dot {V}$$\end{document}V˙O2max) completed three exercise trials in environmental conditions of severe hypoxia (FIO2 0.114), moderate hypoxia (FIO2 0.152), and normoxia (FIO2 0.202). They were instructed to continually adjust their power output to maintain a perceived effort (RPE) of 16, exercising until power output declined to 80% of the peak 30-s power output achieved. Results Exercise time was reduced (severe hypoxia 428 ± 210 s; moderate hypoxia 1044 ± 384 s; normoxia 1550 ± 590 s) according to a reduction in FIO2 (P < 0.05). The rate of oxygen desaturation during the first 3 min of exercise was accelerated in severe hypoxia (− 5.3 ± 2.8% min− 1) relative to moderate hypoxia (− 2.5 ± 1.0% min− 1) and normoxia (− 0.7 ± 0.3% min− 1). Muscle tissue oxygenation did not differ between conditions (P > 0.05). Minute ventilation increased at a faster rate according to a decrease in FIO2 (severe hypoxia 27.6 ± 6.6; moderate hypoxia 21.8 ± 3.9; normoxia 17.3 ± 3.9 L min− 1). Moderate-to-strong correlations were identified between breathing frequency (r = − 0.718, P < 0.001), blood oxygen saturation (r = 0.611, P = 0.002), and exercise performance. Conclusions The primary cues for determining perceived effort relate to progressive arterial hypoxemia and increases in ventilation.
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Choo HC, Peiffer JJ, Lopes-Silva JP, Mesquita RNO, Amano T, Kondo N, Abbiss CR. Effect of ice slushy ingestion and cold water immersion on thermoregulatory behavior. PLoS One 2019; 14:e0212966. [PMID: 30811512 PMCID: PMC6392407 DOI: 10.1371/journal.pone.0212966] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Accepted: 02/12/2019] [Indexed: 11/18/2022] Open
Abstract
Two studies were conducted to examine the effects of ice slushy ingestion (ICE) and cold water immersion (CWI) on thermoregulatory and sweat responses during constant (study 1) and self-paced (study 2) exercise. In study 1, 11 men cycled at 40-50% of peak aerobic power for 60 min (33.2 ± 0.3°C, 45.9 ± 0.5% relative humidity, RH). In study 2, 11 men cycled for 60 min at perceived exertion (RPE) equivalent to 15 (33.9 ± 0.2°C and 42.5 ± 3.9%RH). In both studies, each trial was preceded by 30 min of CWI (~22°C), ICE or no cooling (CON). Rectal temperature (Tre), skin temperature (Tsk), thermal sensation, and sweat responses were measured. In study 1, ICE decreased Tre-Tsk gradient versus CON (p = 0.005) during first 5 min of exercise, while CWI increased Tre-Tsk gradient versus CON and ICE for up to 20 min during the exercise (p<0.05). In study 2, thermal sensation was lower in CWI versus CON and ICE for up to 35-40 min during the exercise (p<0.05). ICE reduced thermal sensation versus CON during the first 20 min of exercise (p<0.05). In study 2, CWI improved mean power output (MPO) by ~8 W, compared with CON only (p = 0.024). In both studies, CWI (p<0.001) and ICE (p = 0.019) delayed sweating by 1-5 min but did not change the body temperature sweating threshold, compared with CON (both p>0.05). Increased Tre-Tsk gradient by CWI improved MPO while ICE reduced Tre but did not confer any ergogenic effect. Both precooling treatments attenuated the thermal efferent signals until a specific body temperature threshold was reached.
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Affiliation(s)
- Hui C. Choo
- Centre for Exercise and Sports Science Research, School of Medical and
Health Sciences, Edith Cowan University, Joondalup, Western Australia,
Australia
- * E-mail:
| | - Jeremiah J. Peiffer
- School of Psychology and Exercise Science, Murdoch University, Murdoch,
Western, Australia, Australia
| | - João P. Lopes-Silva
- School of Physical Education and Sport, University of São Paulo (USP),
São Paulo, São Paulo, Brazil
| | - Ricardo N. O. Mesquita
- Centre for Exercise and Sports Science Research, School of Medical and
Health Sciences, Edith Cowan University, Joondalup, Western Australia,
Australia
| | - Tatsuro Amano
- Faculty of Education, Niigata University, Niigata, Niigata Prefecture,
Japan
| | - Narihiko Kondo
- Laboratory for Applied Human Physiology, Graduate School of Human
Development and Environment, Kobe University, Kobe, Hyōgo Prefecture,
Japan
| | - Chris R. Abbiss
- Centre for Exercise and Sports Science Research, School of Medical and
Health Sciences, Edith Cowan University, Joondalup, Western Australia,
Australia
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The Threshold Ambient Temperature for the Use of Precooling to Improve Cycling Time-Trial Performance. Int J Sports Physiol Perform 2019; 14:323-330. [PMID: 30160552 DOI: 10.1123/ijspp.2018-0310] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
PURPOSE Cycling time-trial performance can be compromised by moderate to high ambient temperatures. It has become commonplace to implement precooling prior to competition to alleviate this performance decline. However, little is known about the ambient temperature threshold above which precooling becomes an effective strategy for enhancing endurance performance. The aim of this study was to investigate the effect of precooling in different environmental temperatures on time-trial (TT) performance. METHODS Trained cyclists completed 2 TTs with (COLD) and without (CON) precooling using an ensemble of ice vest and sleeves in ambient temperatures of 24°C, 27°C, and 35°C. RESULTS TT performance was faster following COLD in both 35°C (6.2%) and 27°C (2.6%; both Ps < .05) but not 24°C (1.2%). Magnitude-based inferential statistics indicate that COLD was very likely beneficial to performance in 35°C, likely beneficial in 27°C, and possibly beneficial in 24°C. Mean power was 2.4%, 2.5%, and 5.6% higher following COLD and considered to be likely beneficial in 24°C and very likely beneficial in 27°C and 35°C. COLD reduced mean skin temperature throughout the warm-up and into the TT in all ambient temperatures (P < .05). Sweat loss was lower following COLD in 24°C and 27°C but not 35°C. There was no effect of COLD on gastrointestinal temperature at any point. CONCLUSIONS Precooling with an ice vest and sleeves is likely to have a positive effect on TT performance at temperatures above 24°C, with a clear relationship between ambient temperature and the magnitude of effect of precooling.
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Otani H, Kaya M, Tamaki A, Goto H, Maughan RJ. Exposure to high solar radiation reduces self-regulated exercise intensity in the heat outdoors. Physiol Behav 2019; 199:191-199. [PMID: 30471385 DOI: 10.1016/j.physbeh.2018.11.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 11/21/2018] [Accepted: 11/21/2018] [Indexed: 10/27/2022]
Abstract
High radiant heat load reduces endurance exercise performance in the heat indoors, but this remains unconfirmed in outdoor exercise. The current study investigated the effects of variations in solar radiation on self-regulated exercise intensity and thermoregulatory responses in the heat outdoors at a fixed rating of perceived exertion (RPE). Ten male participants completed 45-min cycling exercise in hot outdoor environments (about 31°C) at a freely chosen resistance and cadence at an RPE of 13 (somewhat hard). Participants were blinded to resistance, pedal cadence, distance and elapsed time and exercised at three sunlight exposure conditions: clear sky (mean ± SD: 1072 ± 91 W·m-2; HIGH); thin cloud (592 ± 32 W·m-2; MID); and thick cloud (306 ± 52 W·m-2; LOW). Power output (HIGH 96 ± 22 W; MID 103 ± 20 W; LOW 108 ± 20 W) and resistance were lower in HIGH than MID and LOW (P < .001). Pedal cadence was lower, the core-to-skin temperature gradient was narrower, body heat gain from the sun (SHG) was greater and thermal sensation was higher with increasing solar radiation and all variables were different between trials (P < .01). Mean skin temperature was higher in HIGH than MID and LOW (P < .01), but core temperature was similar between trials (P = .485). We conclude that self-regulated exercise intensity in the heat outdoors at a fixed RPE of somewhat hard is reduced with increasing solar radiation because of greater thermoregulatory strain, perceived thermal stress and SHG. This suggests that reduced self-selected exercise intensity during high solar radiation exposure in the heat may prevent excessive core temperature rise.
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Affiliation(s)
- Hidenori Otani
- Faculty of Health Care Sciences, Himeji Dokkyo University, 7-2-1 Kamiono, Himeji, Hyogo 670-8524, Japan.
| | - Mitsuharu Kaya
- Hyogo University of Health Sciences, Kobe, Hyogo 650-8530, Japan
| | - Akira Tamaki
- Hyogo University of Health Sciences, Kobe, Hyogo 650-8530, Japan
| | - Heita Goto
- Kyushu Kyoritsu University, 1-8, Jiyugaoka, Yahatanishi-ku, Kitakyushu, Fukuoka 807-8585, Japan
| | - Ronald J Maughan
- School of Medicine, University of St Andrews, College Gate, St Andrews KY16 9AJ, Fife, UK
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DeMartini-Nolan JK, Martschinske JL, Casa DJ, Lopez RM, Stearns RL, Ganio MS, Coris E. Examining the Influence of Exercise Intensity and Hydration on Gastrointestinal Temperature in Collegiate Football Players. J Strength Cond Res 2019; 32:2888-2896. [PMID: 29210954 DOI: 10.1519/jsc.0000000000002137] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
DeMartini-Nolan, JK, Martschinske, JL, Casa, DJ, Lopez, RM, Stearns, RL, Ganio, MS, and Coris, E. Examining the influence of exercise intensity and hydration on gastrointestinal temperature in collegiate football players. J Strength Cond Res 32(10): 2888-2896, 2018-Debate exists regarding the influence of intensity and hydration on body temperature during American football. The purpose of this study was to observe body core temperature responses with changes in intensity and hydration. Twenty-nine male football players (age = 21 ± 1 year, height = 187 ± 9 cm, mass = 110.1 ± 23.5 kg, body mass index [BMI] = 31.3 ± 5.0, and body surface area [BSA] = 2.34 ± 0.27 m) participated in 8 days of practice in a warm environment (wet bulb globe temperature: 29.6 ± 1.6° C). Participants were identified as starters (S; n = 12) or nonstarters (n = 17) and linemen (L; n = 14) or nonlinemen (NL; n = 15). Variables of interest included core body temperature (T), hydration status, and physical performance characteristics as measured by a global positioning system. Intensity measures of average heart rate (138 ± 9 bpm), low-velocity movement (4.2 ± 1.7%), high-velocity movement (0.6 ± 0.6%), and average velocity (0.36 ± 0.10 m·s) accounted for 42% of the variability observed in T (38.32 ± 0.34° C, r = 0.65, p = 0.01). Hydration measures (percent body mass loss = -1.56 ± 0.80%, urine specific gravity [Usg] = 1.025 ± 0.006, and urine color [Ucol] = 6 ± 1) did not add to the prediction of T (p = 0.83). Metrics of exercise intensity accounted for 39% of the variability observed in maximum T (38.83 ± 0.42° C, r = 0.62, p = 0.02). Hydration measures did not add to this prediction (p = 0.40). Low-velocity movement, high-velocity movement, average velocity, BMI, and BSA were significantly different (p = 0.002, p < 0.001, p = 0.02, p < 0.001, p < 0.001, respectively) between L vs. NL. Heart rate and T were not different between L and NL (p > 0.05). Exercise intensity primarily accounted for the rise in core body temperature. Although L spent less time at higher velocities, T was similar to NL, suggesting that differences in BMI and BSA added to thermoregulatory strain.
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Affiliation(s)
- Julie K DeMartini-Nolan
- Athletic Training Education Program, College of Health Professions, Sacred Heart University, Fairfield, Connecticut
| | - Jessica L Martschinske
- Department of Kinesiology, Korey Stringer Institute, University of Connecticut, Mansfield, Connecticut
| | - Douglas J Casa
- Department of Kinesiology, Korey Stringer Institute, University of Connecticut, Mansfield, Connecticut
| | - Rebecca M Lopez
- Department of Orthopaedics, University of South Florida, Tampa, Florida
| | - Rebecca L Stearns
- Department of Kinesiology, Korey Stringer Institute, University of Connecticut, Mansfield, Connecticut
| | - Matthew S Ganio
- Department of Kinesiology, University of Arkansas, Fayetteville, Arkansas
| | - Eric Coris
- Department of Orthopedics, University of South Florida, Tampa, Florida
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Corbett J, White DK, Barwood MJ, Wagstaff CRD, Tipton MJ, McMorris T, Costello JT. The Effect of Head-to-Head Competition on Behavioural Thermoregulation, Thermophysiological Strain and Performance During Exercise in the Heat. Sports Med 2018; 48:1269-1279. [PMID: 29147922 PMCID: PMC5889783 DOI: 10.1007/s40279-017-0816-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Background It has been suggested that pacing is a thermoregulatory behaviour. We investigated the effect of competition on pacing, performance and thermophysiological strain during exercise in the heat and the psychological factors mediating competition effects. Method Eighteen males (maximum oxygen uptake [VO2max] 3.69 [0.44] L min−1) undertook a preliminary 20-km cool (wet-bulb globe temperature [WBGT] 12 °C) cycling time trial (TT) and three experimental 20-km trials (balanced order): (i) cool TT (CoolSolo); (ii) hot (WBGT 26 °C) TT (HotSolo); (iii) hot head-to-head competition (HotH2H). During TTs, an avatar of the participant’s performance was visible. During HotH2H, participants believed they were competing against another participant, but the competitor’s avatar replicated their own preliminary (cool) TT. Results TTs (min:sec [SD]) slowed with increased ambient temperature [CoolSolo 35:31 (2:11) versus HotSolo 36:10 (2:26); p = 0.011]. This effect was negated by competition; performances were not different between HotH2H [35:17 (1:52)] and CoolSolo (p = 0.160) and were quicker in HotH2H versus HotSolo (p = 0.001). End-exercise rectal temperature, mean body temperature and physiological strain index were (p < 0.05) higher in HotH2H than either solo condition. Despite faster performance and greater thermophysiological strain, rating of perceived exertion (RPE), thermal comfort and sensation, and perceptual strain index were not different between HotH2H and HotSolo. The difference in end-exercise rectal temperature between HotH2H and HotSolo was related to pre-exercise anticipatory heart rate response (r = 0.608, p = 0.010) and participants’ propensity for deliberate risk-taking (B = 0.12, p < 0.001), whereas self-reported resilience predicted change in performance times between HotH2H versus HotSolo (B = − 9.40, p = 0.010). Conclusion Competition changes the relationship between perceived and actual thermophysiological state, altering behavioural thermoregulation and increasing thermophysiological strain; this could increase heat-illness risk. Psychophysiological and psychological measures may identify susceptible individuals.
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Affiliation(s)
- Jo Corbett
- Extreme Environments Laboratory, Department of Sport and Exercise Science, University of Portsmouth, Spinnaker Building, Cambridge Road, Portsmouth, PO1 2ER, UK.
| | - Danny K White
- Extreme Environments Laboratory, Department of Sport and Exercise Science, University of Portsmouth, Spinnaker Building, Cambridge Road, Portsmouth, PO1 2ER, UK
| | - Martin J Barwood
- Department of Sport, Health and Nutrition, Leeds Trinity University, Brownberrie Lane, Horsforth, LS18 5HD, UK
| | - Christopher R D Wagstaff
- Extreme Environments Laboratory, Department of Sport and Exercise Science, University of Portsmouth, Spinnaker Building, Cambridge Road, Portsmouth, PO1 2ER, UK
| | - Michael J Tipton
- Extreme Environments Laboratory, Department of Sport and Exercise Science, University of Portsmouth, Spinnaker Building, Cambridge Road, Portsmouth, PO1 2ER, UK
| | - Terry McMorris
- Extreme Environments Laboratory, Department of Sport and Exercise Science, University of Portsmouth, Spinnaker Building, Cambridge Road, Portsmouth, PO1 2ER, UK.,Institute of Sport, University of Chichester, College Lane, Chichester, PO19 9PE, UK
| | - Joseph T Costello
- Extreme Environments Laboratory, Department of Sport and Exercise Science, University of Portsmouth, Spinnaker Building, Cambridge Road, Portsmouth, PO1 2ER, UK
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Endurance Performance is Influenced by Perceptions of Pain and Temperature: Theory, Applications and Safety Considerations. Sports Med 2018; 48:525-537. [PMID: 29270865 DOI: 10.1007/s40279-017-0852-6] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Models of endurance performance now recognise input from the brain, including an athlete's ability to cope with various non-pleasurable perceptions during exercise, such as pain and temperature. Exercise training can reduce perceptions of both pain and temperature over time, partly explaining why athletes generally have a higher pain tolerance, despite a similar pain threshold, compared with active controls. Several strategies with varying efficacy may ameliorate the perceptions of pain (e.g. acetaminophen, transcranial direct current stimulation and transcutaneous electrical stimulation) and temperature (e.g. menthol beverages, topical menthol products and other cooling strategies, especially those targeting the head) during exercise to improve athletic performance. This review describes both the theory and practical applications of these interventions in the endurance sport setting, as well as the potentially harmful health consequences of their use.
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Wingfield G, Marino F, Skein M. The influence of knowledge of performance endpoint on pacing strategies, perception of effort, and neural activity during 30-km cycling time trials. Physiol Rep 2018; 6:e13892. [PMID: 30426727 PMCID: PMC6234147 DOI: 10.14814/phy2.13892] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 09/24/2018] [Indexed: 12/02/2022] Open
Abstract
It is understood that withholding information during exercise can alter performance during self-paced exercise, though less is known about neural activity during such exercise. The aim of this study was to compare the effects of withholding versus providing distance feedback on perception, muscular activation, and cerebral activity during cycling time trials (TT). Nine well-trained male cyclists randomly completed 2 x 30-km TT, with provision of performance information and distance feedback (known; KTT), and without performance information and remaining distance (unknown; UTT). Prefrontal cortex (PFC) hemoglobin concentration, electroencephalogy (EEG) responses of the parietal lobe (PL) and motor cortex (MC), and surface electromyogram (EMG) of the right thigh were monitored throughout the TTs, in addition to heart rate (HR), rating of perceived exertion (RPE), and power output (PO). Time to completion was shorter for the KTT compared to UTT (51.04 ± 3.26 vs. 49.25 ± 3.57 min, P = 0.01). There were no differences evident for RPE between conditions (P > 0.50). However, during the final 2 km, the KTT presented higher PO (P ≤ 0.05), HR (P = 0.03) and MC, and PL EEG activity (d = 0.51-0.71) in addition to increased tissue hemoglobin index (nTHI) and oxygen extraction (HHb) (d = 0.55-0.65) compared to the UTT. In conclusion, when withholding information pertaining to remaining distance, performance was reduced due to the application of a conservative pacing strategy. In addition, the increase in HHb across the PFC was strongly correlated with PO (r = 0.790; P < 0.001) suggesting knowledge about remaining distance may increase activation across the PFC. Further, it appears that changes within the PFC may play a role in the regulation of cycling performance.
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Affiliation(s)
- Georgia Wingfield
- School of Exercise Science, Sport and HealthCharles Sturt UniversityBathurstNew South WalesAustralia
| | - Frank Marino
- School of Exercise Science, Sport and HealthCharles Sturt UniversityBathurstNew South WalesAustralia
| | - Melissa Skein
- School of Exercise Science, Sport and HealthCharles Sturt UniversityBathurstNew South WalesAustralia
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Bright FM, Chaseling GK, Jay O, Morris NB. Self-paced exercise performance in the heat with neck cooling, menthol application, and abdominal cooling. J Sci Med Sport 2018; 22:371-377. [PMID: 30270195 DOI: 10.1016/j.jsams.2018.09.225] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 08/19/2018] [Accepted: 09/06/2018] [Indexed: 02/06/2023]
Abstract
OBJECTIVES To investigate whether the exercise performance benefits with neck cooling in the heat are attributable to neck-specific cooling, general body cooling, a cooler site-specific thermal perception or a combination of the above. DESIGN Counter-balanced crossover design. METHODS Twelve healthy participants cycled in the heat (34°C, 30% relative humidity), at a power output (PO) self-selected to maintain a fixed rating of perceived exertion (RPE) of 16. Each participant underwent four experimental trials: no cooling (CON), neck cooling (NEC), abdominal cooling (ABD), or neck cooling with menthol (MEN). Participants cycled for 90min or until their workload reduced by <70% of their initial PO. Changes in PO, rectal temperature (Tre), mean skin temperature (Tsk), whole-body thermal sensation (TSwb) and thermal sensation of the neck (TSneck) were recorded throughout. RESULTS The mean reduction in PO throughout exercise was similar (p=0.431) for CON (175±10W), NEC (176 ±12W), ABD (172±13W) and MEN (174±12W). The ΔTre at the end of exercise was similar (p=0.874) for CON (0.83±0.5°C), NEC (0.85±0.5°C), ABD (0.82±0.5°C) and MEN (0.81±0.5°C). TSwb was cooler (p<0.013) in MEN (125±8mm) compared to CON (146±19mm), NEC (135±11mm) and ABD (141±16mm). CONCLUSIONS No differences in exercise performance or thermal strain were observed in any of the cooling trials compared to the CON trial, despite significantly cooler TSwb values in the MEN and NEC trials compared to the CON trial. These findings differ from previous observations and highlight that the benefit of neck cooling may be situation dependent.
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Affiliation(s)
- Felicity M Bright
- Thermal Ergonomics Laboratory, Faculty of Health Sciences, University of Sydney, Australia
| | - Georgia K Chaseling
- Thermal Ergonomics Laboratory, Faculty of Health Sciences, University of Sydney, Australia
| | - Ollie Jay
- Thermal Ergonomics Laboratory, Faculty of Health Sciences, University of Sydney, Australia; Charles Perkins Centre, University of Sydney, Australia
| | - Nathan B Morris
- Thermal Ergonomics Laboratory, Faculty of Health Sciences, University of Sydney, Australia; Center for Technology Research and Innovation, Cyprus; Department of Nutrition, Exercise and Sports, University of Copenhagen, Denmark.
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Borg DN, Stewart IB, Costello JT, Drovandi CC, Minett GM. The impact of environmental temperature deception on perceived exertion during fixed-intensity exercise in the heat in trained-cyclists. Physiol Behav 2018; 194:333-340. [PMID: 29933029 DOI: 10.1016/j.physbeh.2018.06.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 06/14/2018] [Accepted: 06/18/2018] [Indexed: 11/29/2022]
Abstract
PURPOSE This study examined the effect of environmental temperature deception on the rating of perceived exertion (RPE) during 30 min of fixed-intensity cycling in the heat. METHODS Eleven trained male cyclists completed an incremental cycling test and four experimental trials. Trials consisted of 30 min cycling at 50% Pmax, once in 24 °C (CON) and three times in 33 °C. In the hot trials, participants were provided with accurate temperature feedback (HOT), or were deceived to believe the temperature was 28 °C (DECLOW) or 38 °C (DECHIGH). During cycling, RPE was recorded every 5 min. Rectal and skin temperature, heart rate and oxygen uptake were continuously measured. Data were analysed using linear mixed model methods in a Bayesian framework, magnitude-based inferences (Cohens d), and the probability that d exceeded the smallest worthwhile change. RESULTS RPE was higher in the heat compared to CON, but not statistically different between the hot conditions (mean [95% credible interval]; DECLOW: 13.0 [11.9, 14.1]; HOT: 13.0 [11.9, 14.1]; DECHIGH: 13.1 [12.0, 14.2]). Heart rate was significantly higher in DECHIGH (141 b·min-1 [132, 149]) compared to all other conditions (DECLOW: 138 b·min-1 [129, 146]; HOT: 138 b·min-1 [129, 145]) after 10 min; however, this did not alter RPE. All other physiological variables did not differ between the hot conditions. CONCLUSION Participants were under the impression they were cycling in different environments; however, this did not influence RPE. These data suggest that for trained cyclists, an awareness of environmental temperature does not contribute to the generation of RPE when exercising at a fixed intensity in the heat.
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Affiliation(s)
- D N Borg
- Institute of Health and Biomedical Innovation and School of Exercise and Nutrition Sciences, Queensland University of Technology, Brisbane, Queensland, Australia.
| | - I B Stewart
- Institute of Health and Biomedical Innovation and School of Exercise and Nutrition Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
| | - J T Costello
- Extreme Environments Laboratory, Department of Sport and Exercise Science, University of Portsmouth, Portsmouth, United Kingdom
| | - C C Drovandi
- School of Mathematical Sciences and the Australian Research Council Centre of Excellence for Mathematical and Statistical Frontiers, Queensland University of Technology, Brisbane, Queensland, Australia
| | - G M Minett
- Institute of Health and Biomedical Innovation and School of Exercise and Nutrition Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
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Keller JL, Housh TJ, Hill EC, Smith CM, Schmidt RJ, Johnson GO. Neuromuscular responses of recreationally active women during a sustained, submaximal isometric leg extension muscle action at a constant perception of effort. Eur J Appl Physiol 2018; 118:2499-2508. [DOI: 10.1007/s00421-018-3976-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 08/23/2018] [Indexed: 11/28/2022]
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Jeffries O, Goldsmith M, Waldron M. L-Menthol mouth rinse or ice slurry ingestion during the latter stages of exercise in the heat provide a novel stimulus to enhance performance despite elevation in mean body temperature. Eur J Appl Physiol 2018; 118:2435-2442. [PMID: 30128853 PMCID: PMC6182327 DOI: 10.1007/s00421-018-3970-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 08/11/2018] [Indexed: 02/07/2023]
Abstract
Purpose This study investigated the effects of l-menthol mouth rinse and ice slurry ingestion on time to exhaustion, when administered at the latter stages (~ 85%) of baseline exercise duration in the heat (35 °C). Method Ten male participants performed four time to exhaustion (TTE) trials on a cycle ergometer at 70% Wmax. In a randomized crossover design, (1) placebo-flavored non-calorific mouth rinse, (2) l-menthol mouth rinse (0.01%), or (3) ice ingestion (1.25 g kg−1), was administered at 85% of participants’ baseline TTE. Time to exhaustion, core and skin temperature, heart rate, rating of perceived effort, thermal comfort and thermal sensation were recorded. Results From the point of administration at 85% of baseline TTE, exercise time was extended by 1% (placebo, 15 s), 6% (l-menthol, 82 s) and 7% (ice, 108 s), relative to baseline performance (P = 0.036), with no difference between l-menthol and ice (P > 0.05). Core temperature, skin temperature, and heart rate increased with time but did not differ between conditions (P > 0.05). Thermal sensation did not differ significantly but demonstrated a large effect size (P = 0.080; \documentclass[12pt]{minimal}
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\begin{document}$$\eta _{{\text{p}}}^{2}$$\end{document}ηp2 = 0.260). Conclusion These results indicate that both thermally cooling and non-thermally cooling oral stimuli have an equal and immediate behavioral, rather than physiological, influence on exhaustive exercise in the heat.
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Affiliation(s)
- Owen Jeffries
- School of Biomedical Sciences, Faculty of Medical Sciences, Newcastle University, Cookson Building, Newcastle upon Tyne, NE2 4HH, UK. .,School of Sport, Health and Applied Science, St Mary's University, London, UK.
| | - Matthew Goldsmith
- School of Sport, Health and Applied Science, St Mary's University, London, UK
| | - Mark Waldron
- School of Sport, Health and Applied Science, St Mary's University, London, UK.,School of Science and Technology, University of New England, Armidale, NSW, Australia
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