The importance of the brain in sports was recently confirmed by the negative effect of mental fatigue (MF) on sport-specific psychomotor skills. Creatine supplementation improves strength, but can also improve cognitive functioning. To explore the role of creatine in combatting MF, we evaluated whether creatine supplementation counteracts the MF-associated impairment in sport-specific psychomotor skills.
In 23°C, 14 healthy participants (4F 10M; mean ± SD; age:24 ± 3 y; mass:74 ± 13 kg; height:179 ± 9 cm) performed -counterbalanced, crossover and double blinded- a 90-min mentally fatiguing task (i.e. Stroop task) in two different conditions: after a 7-day creatine supplementation (CR; 20 g/day) and after a 7-day calcium lactate supplementation (PLAC; placebo), separated by a 5-week washout. In both conditions, a 7-min sport-specific visuomotor task, a dynamic handgrip strength endurance task and a 3-min Flanker task was performed before and after the mentally fatiguing task. Physiological and perceptual responses were measured throughout the protocol.
Handgrip strength endurance was higher in CR compared to PLAC (p=0.022). MF impaired visuomotor response time (+4.4%; p=0.022) and Flanker accuracy (-5.0%; p=0.009) in both conditions. Accuracy on the Stroop task was higher in CR compared to PLAC (+4.9%; p=0.026). Within the perceptual and physiological parameters, only motivation and vigor (p≤0.027) were lower in CR compared to PLAC.
Creatine supplementation improved physical (strength endurance) and prolonged cognitive (Stroop accuracy) performance, yet it did not combat mental fatigue-induced impairments in short sport-specific psychomotor or cognitive (Flanker) performance. These results warrant further investigation in the potential role of creatine in combatting the MF-associated decrements in prolonged (e.g. 90-min soccer game) sport performance, and suggest a role of brain-phosphocreatine in MF.
Human Physiology and Sports Physiotherapy Research Group, Vrije Universiteit Brussel, Belgium
Corresponding author: Romain Meeusen Human Physiology and Sports Physiotherapy Research Group Pleinlaan 2 B-1050 Brussels, Belgium Email: email@example.com Tel: +32 2 629 27 32
The authors declare that the results of the study are presented clearly, honestly, and without fabrication, falsification, or inappropriate data manipulation. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. The results of the present study do not constitute endorsement by ACSM. No conflict of interest is declared by the authors.
Accepted for Publication: 5 August 2019