Introduction
twitch, peripheral fatigue, Cowden, muscle fatigue
Endurance performance relies heavily on the ability to sustain aerobic exercise over prolonged periods of time up to the point of exhaustion, which is traditionally thought to represent the culmination of progressive muscle fatigue (Allen et al. One of the key psychological aspects that supports high performance is the concept of mental toughness. Mental toughness has been defined as having a single-minded focus on excellence even as the demands experienced during competition change (Cowden The duration of mental training needed to elucidate the maximal performance response is also unknown. Recent successful mental training research ranged from a professional soccer paradigm consisting of an initial 1-h imagery session followed by a booster session 6 weeks later increasing grit (Rhodes et al. The purpose of this study was to examine the effect of mental training on endurance performance and to determine the minimal dose of mental training needed to bring about an increase in endurance performance while also attempting to determine the physiological changes that would accompany this increased performance. This was done by utilizing a time trial to exhaustion in a controlled laboratory study. Participants performed four time trials, each separated by 1 week, with mental training taking place every day during each week. It was hypothesized, given previous research, that mental training would improve performance, even with as little as 1 week of mental training, and would occur with reciprocal changes in physiological variables such as rectus femoris electromyography, peripheral fatigue as measured through potentiated twitch (