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Controlling rectal and muscle temperatures: Can we offset diurnal variation in repeated sprint performance?
- Source :
- Chronobiology International: The Journal of Biological & Medical Rhythm Research; Jul2018, Vol. 35 Issue 7, p959-968, 10p, 1 Diagram, 1 Chart, 2 Graphs
- Publication Year :
- 2018
-
Abstract
- The present study investigated whether increasing morning rectal temperatures (T<subscript>rec</subscript>) to resting.evening levels, or decreasing evening T<subscript>rec</subscript> or muscle (T<subscript>m</subscript>) 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 (<inline-graphic></inline-graphic> peak) 60.6 ± 4.6 mL kg min<superscript>−1</superscript>, 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 (M<subscript>E</subscript>, on a motorised treadmill) until T<subscript>rec</subscript> reached evening levels; and two cool-down evening trials (in 16-17°C water) until T<subscript>rec</subscript> (E<subscript>Mrec</subscript>) or T<subscript>m</subscript> (E<subscript>Mmuscle</subscript>) 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. T<subscript>rec</subscript> and T<subscript>m</subscript> measurements were taken at the start of the protocol and following the warm-up or cool-down period. Values for T<subscript>rec</subscript> and T<subscript>m</subscript> 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 T<subscript>rec</subscript> and T<subscript>m</subscript> 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 T<subscript>rec</subscript> and T<subscript>m</subscript> 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. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 07420528
- Volume :
- 35
- Issue :
- 7
- Database :
- Complementary Index
- Journal :
- Chronobiology International: The Journal of Biological & Medical Rhythm Research
- Publication Type :
- Academic Journal
- Accession number :
- 131350901
- Full Text :
- https://doi.org/10.1080/07420528.2018.1444626