1. Controlling rectal and muscle temperatures: Can we offset diurnal variation in repeated sprint performance?
- Author
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Pullinger SA, Oksa J, Brocklehurst EL, Iveson RP, Newlove A, Burniston JG, Doran DA, Waterhouse JM, and Edwards BJ
- Subjects
- Adolescent, Adult, Biomechanical Phenomena physiology, Circadian Rhythm physiology, Exercise Test, Female, Humans, Male, Temperature, Young Adult, Body Temperature physiology, Body Temperature Regulation physiology, Exercise physiology, Muscle, Skeletal physiology
- Abstract
The present study investigated whether increasing morning rectal temperatures (T
rec ) to resting.evening levels, or decreasing evening Trec or muscle (Tm ) temperatures to morning values, would influence repeated sprint (RS) performance in a causal manner. Twelve trained males underwent five sessions [age (mean ± SD) 21.8 ± 2.6 yr, peak oxygen uptake ([Formula: see text] peak) 60.6 ± 4.6 mL kg min-1 , stature 1.78 ± 0.07 m and body mass 76.0 ± 6.3 kg]. These included a control morning (M, 07:30 h) and evening (E, 17:30 h) session (5-min warm-up), and three further sessions consisting of a warm-up morning trial (ME , on a motorised treadmill) until Trec reached evening levels; and two cool-down evening trials (in 16-17°C water) until Trec (EMrec ) or Tm (EMmuscle ) values reached morning temperatures, respectively. All sessions included a 3 × 3-s task-specific warm-up followed by 10 × 3-s RS with 30-s recoveries performed on a non-motorised treadmill. Trec and Tm measurements were taken at the start of the protocol and following the warm-up or cool-down period. Values for Trec and Tm were higher in the evening compared to morning values (0.45°C and 0.57°C, P < 0.05). RS performance was lower in the M for distance covered (DC), average power (AP) and average velocity (AV) (9-10%, P < 0.05). Pre-cooling Trec and Tm in the evening reduced RS performance to levels observed in the morning (P < 0.05). However, an active warm-up resulted in no changes in morning RS performance. Diurnal variation in Trec and Tm is not wholly accountable for time-of-day oscillations in RS performance on a non-motorised treadmill; the exact mechanism(s) for a causal link between central temperature and human performance are still unclear and require more research.- Published
- 2018
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