Abstract
Purpose: To verify whether caffeine (CAF) could increase the prefrontal cortex (PFC) activation
and improve 20 km cycling time trial (TT20km) performance in mentally fatigued cyclists. Methods:
After preliminary TT20km, twelve recreational cyclists (VO2MAX of 58.9 ± 6.2 mL∙kg∙min-1
)
performed a familiarization with a cognitive test to induce mental fatigue (MF) and psychological
scales. Thereafter, they performed: 2) a baseline TT20km; 3) a mentally fatigued TT20km (MF); 4 and
5) a mentally fatigued TT20km after CAF (MF+CAF) or placebo (MF+PLA) ingestion, in a doubleblind, counterbalanced design. Performance and psychological responses were obtained throughout
the TT20km, while PFC electroencephalography (EEG) theta wave was obtained before and after the
mental fatigue test. Results: The mental fatigue-induced increase in EEG theta wave (↑ ~ 4.8 %)
was reverted with CAF (↓ 8.8 %) and PLA ingestion (↓ 4.8 %). CAF improved TT20km performance
in mentally fatigued cyclists by reducing time (p = 0.00; ↓ ~1.7 %) and increasing WMEAN (p = 0.00;
↑ ~3.6%), when compared to MF+PLA. The RPE-power output ratio was lower (p = 0.01), but
affect (p = 0.018), motivation (p = 0.033) and emotional arousal (p = 0.001) were greater
throughout the TT20km in MF+CAF than in MF+PLA. Conclusions: CAF ingestion improved
TT20km performance and psychological responses in mentally fatigued cyclists, despite the unaltered
PFC activation.
and improve 20 km cycling time trial (TT20km) performance in mentally fatigued cyclists. Methods:
After preliminary TT20km, twelve recreational cyclists (VO2MAX of 58.9 ± 6.2 mL∙kg∙min-1
)
performed a familiarization with a cognitive test to induce mental fatigue (MF) and psychological
scales. Thereafter, they performed: 2) a baseline TT20km; 3) a mentally fatigued TT20km (MF); 4 and
5) a mentally fatigued TT20km after CAF (MF+CAF) or placebo (MF+PLA) ingestion, in a doubleblind, counterbalanced design. Performance and psychological responses were obtained throughout
the TT20km, while PFC electroencephalography (EEG) theta wave was obtained before and after the
mental fatigue test. Results: The mental fatigue-induced increase in EEG theta wave (↑ ~ 4.8 %)
was reverted with CAF (↓ 8.8 %) and PLA ingestion (↓ 4.8 %). CAF improved TT20km performance
in mentally fatigued cyclists by reducing time (p = 0.00; ↓ ~1.7 %) and increasing WMEAN (p = 0.00;
↑ ~3.6%), when compared to MF+PLA. The RPE-power output ratio was lower (p = 0.01), but
affect (p = 0.018), motivation (p = 0.033) and emotional arousal (p = 0.001) were greater
throughout the TT20km in MF+CAF than in MF+PLA. Conclusions: CAF ingestion improved
TT20km performance and psychological responses in mentally fatigued cyclists, despite the unaltered
PFC activation.
| Original language | English |
|---|---|
| Pages (from-to) | 41-48 |
| Number of pages | 8 |
| Journal | Physiology and Behavior |
| Volume | 204 |
| Early online date | 10 Feb 2019 |
| DOIs | |
| Publication status | Published - 15 May 2019 |
Keywords
- Fatigue
- Placebo
- RPE
- Pacing
- Supplementation