Pushing the limits of performance. is it really mind over matter? an investigation into the effects of menthol mouth rinsing and the capacity for fatigue amelioration in trained adolescent male cyclists under heat stress

Abstract

This thesis investigated the effects of menthol (MEN) mouth rinsing (MR) on performance responses in trained adolescent male athletes during a modified variable power cycle test (M-VCT). Participants (n=11) cycled for 30-min in hot conditions (31.4±0.9 °C, 23.4±3.7% RH) on two occasions. In a randomized crossover design, (1) menthol MR (0.01%) or (2) placebo (PLA) MR, was administered at 6-min intervals. Power, distance, core temperature, heart rate, surface electromyography, perceptual responses (exertion, thermal stimulation, fatigue, and feeling), and blood lactate were recorded. The MEN MR significantly improved mean power output by 1.81±1.57% relative to PLA (p=<0.001, 95% CI= [1.73-4.46], ES= 1.53). Physiological and perceptual measures did not differ between trials. While individual responses varied to MEN, results demonstrate that a nonthermal cooling agent that acts on the CNS can benefit power regulation during a stochastic cycling task without causing additional decline in perception, as suggested by the central fatigue hypothesis.