A monetary reward prolongs cycling time-to-task failure without altering performance fatigability and perceptual responses

This study aimed to determine the effects of an unexpected monetary reward on time-to-task failure (TTF) and on measures of performance and perceptual fatigability in healthy young adults. During two separate sessions, 18 participants (9 females) completed a TTF within the heavy-intensity domain (HVY_TTF), which was followed, after 1 min of rest, by a TTF within the extreme-intensity domain (EXT_TTF). In the second HVY_TTF session, an unexpected monetary reward was offered prior the self-anticipated task failure. Before and after each trial, neuromuscular fatigue was assessed at baseline (NMF_BSLN) and following HVY_TTF (NMF_HVY) and EXT_TTF (NMF_EXT) using femoral nerve stimulation during and after a quadriceps muscle isometric maximal voluntary contraction (IMVC). The unexpected monetary reward significantly increased HVY_TTF (46 ± 16 min vs. 53 ± 22 min; <i>P</i> = 0.011), while reducing the following EXT_TTF (68 ± 17 s vs. 57 ± 17 s; <i>P</i> = 0.034). IMVC (∼-31%), Db₁₀ (∼-42%), Db₁₀₀ (∼-21%), low-frequency fatigue (∼-26%), and potentiated twitch force (∼-37%) were all reduced from NMF_BSLN to NMF_HVY (<i>P</i> < 0.001) with no further declines following NMF_EXT (<i>P</i> > 0.005) except for Db₁₀ (∼-9%, <i>P</i> = 0.007) and potentiated twitch force (∼-9%; <i>P</i> < 0.001). Voluntary activation did not change from NMF_BSLN to NMF_HVY or from NMF_BSLN to NMF_EXT following either of the conditions (<i>P</i> > 0.005). These findings indicate that an unexpected monetary reward can increase exercise performance within the heavy-intensity domain. This improvement while being associated with no further reductions in neuromuscular indices of fatigue, it impaired subsequent extreme-intensity performance.<b>NEW & NOTEWORTHY</b> Exercise performance within the heavy-intensity domain was extended by an unexpected monetary reward offered when approaching task failure. The extended duration was not accompanied by further impairments in neuromuscular indices of fatigue nor changes in perceptual responses. However, subsequent exercise performance was reduced. Overall, these findings demonstrate a dissociation among different indices of performance and perceptual fatigability. Furthermore, they give a new perspective on how the type and time of a motivational strategy can influence training or competition performance.