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The effect of high versus low intensity heat acclimation on performance and neuromuscular responses.
J Therm Biol 2016; 58:50-9JT

Abstract

This study examined the effect of exercise intensity and duration during 5-day heat acclimation (HA) on cycling performance and neuromuscular responses. 20 recreationally trained males completed a 'baseline' trial followed by 5 consecutive days HA, and a 'post-acclimation' trial. Baseline and post-acclimation trials consisted of maximal voluntary contractions (MVC), a single and repeated countermovement jump protocol, 20km cycling time trial (TT) and 5×6s maximal sprints (SPR). Cycling trials were undertaken in 33.0 ± 0.8°C and 60 ± 3% relative humidity. Core (Tcore), and skin temperatures (Tskin), heart rate (HR), rating of perceived exertion (RPE) and thermal sensation were recorded throughout cycling trials. Participants were assigned to either 30min high-intensity (30HI) or 90min low-intensity (90LI) cohorts for HA, conducted in environmental conditions of 32.0 ± 1.6°C. Percentage change time to complete the 20km TT for the 90LI cohort was significantly improved post-acclimation (-5.9 ± 7.0%; P=0.04) compared to the 30HI cohort (-0.18 ± 3.9%; P<0.05). The 30HI cohort showed greatest improvements in power output (PO) during post-acclimation SPR 1 and 2 compared to 90LI (546 ± 128W and 517 ± 87W, respectively; P<0.02). No differences were evident for MVC within 30HI cohort, however, a reduced performance indicated by % change within the 90LI (P=0.04). Compared to baseline, mean Tcore was reduced post-acclimation within the 30HI cohort (P=0.05) while mean Tcore and HR were significantly reduced within the 90LI cohort (P=0.01 and 0.04, respectively). Greater physiological adaptations and performance improvements were noted within the 90LI cohort compared to the 30HI. However, 30HI did provide some benefit to anaerobic performance including sprint PO and MVC. These findings suggest specifying training duration and intensity during heat acclimation may be useful for specific post-acclimation performance.

Authors+Show Affiliations

School of Exercise Science, Sport and Health, Charles Sturt University, Bathurst, NSW, Australia. Electronic address: gwingfield@csu.edu.au.Research Institute for Sport and Exercise, University of Canberra, Canberra, Australia; Department of Physiology, Australian Institute of Sport, Canberra, ACT Australia.School of Exercise and Nutrition Sciences, Queensland University of Technology, Kelvin Grove, QLD, Australia; Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, QLD, Australia.School of Exercise Science, Sport and Health, Charles Sturt University, Bathurst, NSW, Australia.School of Exercise Science, Sport and Health, Charles Sturt University, Bathurst, NSW, Australia.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

27157334

Citation

Wingfield, Georgia L., et al. "The Effect of High Versus Low Intensity Heat Acclimation On Performance and Neuromuscular Responses." Journal of Thermal Biology, vol. 58, 2016, pp. 50-9.
Wingfield GL, Gale R, Minett GM, et al. The effect of high versus low intensity heat acclimation on performance and neuromuscular responses. J Therm Biol. 2016;58:50-9.
Wingfield, G. L., Gale, R., Minett, G. M., Marino, F. E., & Skein, M. (2016). The effect of high versus low intensity heat acclimation on performance and neuromuscular responses. Journal of Thermal Biology, 58, pp. 50-9. doi:10.1016/j.jtherbio.2016.02.006.
Wingfield GL, et al. The Effect of High Versus Low Intensity Heat Acclimation On Performance and Neuromuscular Responses. J Therm Biol. 2016;58:50-9. PubMed PMID: 27157334.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The effect of high versus low intensity heat acclimation on performance and neuromuscular responses. AU - Wingfield,Georgia L, AU - Gale,Rachel, AU - Minett,Geoffrey M, AU - Marino,Frank E, AU - Skein,Melissa, Y1 - 2016/03/24/ PY - 2015/10/21/received PY - 2016/02/19/accepted PY - 2016/5/10/entrez PY - 2016/5/10/pubmed PY - 2017/3/21/medline KW - Anaerobic KW - Cycling KW - Heat training KW - Self-paced SP - 50 EP - 9 JF - Journal of thermal biology JO - J. Therm. Biol. VL - 58 N2 - This study examined the effect of exercise intensity and duration during 5-day heat acclimation (HA) on cycling performance and neuromuscular responses. 20 recreationally trained males completed a 'baseline' trial followed by 5 consecutive days HA, and a 'post-acclimation' trial. Baseline and post-acclimation trials consisted of maximal voluntary contractions (MVC), a single and repeated countermovement jump protocol, 20km cycling time trial (TT) and 5×6s maximal sprints (SPR). Cycling trials were undertaken in 33.0 ± 0.8°C and 60 ± 3% relative humidity. Core (Tcore), and skin temperatures (Tskin), heart rate (HR), rating of perceived exertion (RPE) and thermal sensation were recorded throughout cycling trials. Participants were assigned to either 30min high-intensity (30HI) or 90min low-intensity (90LI) cohorts for HA, conducted in environmental conditions of 32.0 ± 1.6°C. Percentage change time to complete the 20km TT for the 90LI cohort was significantly improved post-acclimation (-5.9 ± 7.0%; P=0.04) compared to the 30HI cohort (-0.18 ± 3.9%; P<0.05). The 30HI cohort showed greatest improvements in power output (PO) during post-acclimation SPR 1 and 2 compared to 90LI (546 ± 128W and 517 ± 87W, respectively; P<0.02). No differences were evident for MVC within 30HI cohort, however, a reduced performance indicated by % change within the 90LI (P=0.04). Compared to baseline, mean Tcore was reduced post-acclimation within the 30HI cohort (P=0.05) while mean Tcore and HR were significantly reduced within the 90LI cohort (P=0.01 and 0.04, respectively). Greater physiological adaptations and performance improvements were noted within the 90LI cohort compared to the 30HI. However, 30HI did provide some benefit to anaerobic performance including sprint PO and MVC. These findings suggest specifying training duration and intensity during heat acclimation may be useful for specific post-acclimation performance. SN - 0306-4565 UR - https://www.unboundmedicine.com/medline/citation/27157334/The_effect_of_high_versus_low_intensity_heat_acclimation_on_performance_and_neuromuscular_responses_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0306-4565(15)30164-9 DB - PRIME DP - Unbound Medicine ER -