Revisiting the acute effects of resistance exercise on motor imagery ability

Abstract

Motor imagery (MI) shares psychological and physiological similarities with the physical practice of the same action. Yet, it remains unclear whether fatigue elicited by exercise is likely to affect MI ability. Fourteen participants performed MI of a self-paced walking sequence of 22\u2009m before and after a resistance exercise eliciting selective muscle fatigue from upper and lower limbs. We indexed MI ability using psychometric and behavioral methods. Electromyography of the quadriceps was also recorded during physical practice trials of the walking sequence. For both experimental conditions, we recorded improved temporal congruence between MI and physical practice of the walking sequence (9.89%, 95% CI [7.03, 12.75], p\u2009<\u20090.01). Vividness decreased immediately after the fatiguing exercise (6.35%, 95% CI [5.18, 7.51], p\u2009<\u20090.05), before rapidly returning to pre-fatigue values during recovery trials. The results challenge the hypothesis of an effect of acute fatigue elicited by a resistance exercise on MI ability, i.e. restricted to MI tasks focusing on fatigued effectors. The beneficial effects of fatigue conditions on behavioral indexes of MI ability are discussed in the broader context of psychobiological fatigue models linking perceived exertion with the reallocation of attentional resources. The general perception of fatigue, rather than local muscle fatigue, appeared linked to the acute effects of fatigue on MI ability.