The objective of this study was to propose an alternative method (MAOD_ALT) to estimate the maximal accumulated oxygen deficit (MAOD) using only one supramaximal exhaustive test. Nine participants performed the following tests: (a) a maximal incremental exercise test, (b) six submaximal constant workload tests, and (c) a supramaximal constant workload test. Traditional MAOD was determined by calculating the difference between predicted O₂ demand and accumulated O₂ uptake during the supramaximal test. MAOD_ALT was established by summing the fast component of excess post-exercise oxygen consumption and the O₂ equivalent for energy provided by blood lactate accumulation, both of which were measured during the supramaximal test. There was no significant difference between MAOD (2.82±0.45 L) and MAOD_ALT (2.77±0.37 L) (p=0.60). The correlation between MAOD and MAOD_ALT was also high (r=0.78; p=0.014). These data indicate that the MAOD_ALT can be used to estimate the MAOD.

Purpose: We sought to verify if alterations in prefrontal cortex (PFC) activation and psychological responses would play along with impairments in pacing and performance of mentally fatigued cyclists. Materials and Methods: Eight recreational cyclists performed two preliminary sessions to familiarize them with the rapid visual information processing (RVP) test, psychological scales and 20 km cycling time trial (TT_20km) (session 1), as well as to perform a VO_2MAX test (session 2). Thereafter, they performed a TT_20km either after a RVP test (30 min) or a time-matched rest control session (session 3 and 4 in counterbalanced order). Performance and psychological responses were obtained throughout the TT_20km while PFC electroencephalography (EEG) was obtained at 10 and 20 km of the TT_20km and throughout the RVP test. Increases in EEG theta band power indicated a mental fatigue condition. Repeated-measures mixed models design and post-hoc effect size (ES) were used in comparisons. Results: Cyclists completed the trial ~2.7% slower in mental fatigue (34.3 ± 1.3 min) than in control (33.4 ± 1.1 min, p = 0.02, very large ES), with a lower W_MEAN (224.5 ± 17.9 W vs. 240.2 ± 20.9 W, respectively; p = 0.03; extremely large ES). There was a higher EEG theta band power during RVP test (p = 0.03; extremely large ES), which remained during the TT_20km (p = 0.01; extremely large ES). RPE increased steeper in mental fatigue than in control, together with isolated reductions in motivation at 2th km (p = 0.04; extremely large ES), felt arousal at the 2nd and 4th km (p = 0.01; extremely large ES), and associative thoughts to exercise at the 6th and 16th km (p = 0.02; extremely large ES) of the TT_20km. Conclusions: Mentally fatigued recreational cyclists showed impaired performance, altered PFC activation and faster increase in RPE during a TT_20km.

Udy was to identify the main determinants of the self-selected pacing strategy during a 10-km running time trial. Twenty eight male long-distance runners performed the following tests: (a) maximal incremental treadmill test, (b) economy running test, (c) maximum dynamic strength test, and (d) 10-km running time trial on an outdoor track. A stepwise multiple regression model was used to identify the contribution of rating of perceived exertion (RPE), physiological, and muscular parameters on the pacing strategy adopted by athletes. In the start phase (first 400 m), RPE accounted for 72% (p = 0.001) of the pacing variance. Peak treadmill speed (PTS) measured during a maximal incremental test explained 52% (p = 0.001) of the pacing variance during the middle phase (400–9,600 m), whereas maximal oxygen uptake and maximum dynamic strength accounted for additional 23% (p = 0.002) and 5% (p = 0.003), respectively. In the end phase (last 400 m), PTS accounted alone for 66% (p = 0.003) of the pacing variance. These data suggest that predictors of the pacing strategy during a 10-km running time trial have a transitional behavior from perceptive (start phase) to muscular and physiological factors (middle and end phases)....