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Caffeine increases peripheral fatigue in low- but not in high-performing cyclists
Pamela S Santos1,2, Leandro C Felippe1,3, Guilherme A Ferreira1,3
1Human Performance Research Group, Academic Department of Physical Education, Federal University of Technology - Parana (UTFPR), Neoville, Curitiba, PR 81310-900, Brazil.
Summary
Caffeine enhances cycling performance but increases muscle fatigue in low-performing athletes, not high-performing ones. High-performing cyclists show better tolerance to central fatigue during intense trials.
Area of Science:
- Sports Science
- Exercise Physiology
- Nutritional Biochemistry
Background:
- Caffeine is a widely used ergogenic aid known to improve endurance performance.
- The impact of caffeine on neuromuscular fatigue may differ based on an athlete's performance level.
- Understanding these differences is crucial for optimizing caffeine use in sports.
Purpose of the Study:
- To investigate how cyclists' performance levels influence caffeine-induced neuromuscular fatigue after a 4-km cycling time trial.
- To differentiate the effects of caffeine on central and peripheral fatigue markers between high-performing and low-performing cyclists.
- To determine if performance improvements from caffeine come at a cost of increased fatigue in different athlete groups.
Main Methods:
- Nineteen cyclists completed a 4-km cycling time trial (TT) after ingesting either caffeine (5 mg·kg-1) or a placebo.
- Neuromuscular fatigue was assessed by measuring changes in voluntary activation (VA) and potentiated 1 Hz force twitch (Qtw,pot).
- Participants were categorized as high-performing (HP) or low-performing (LP) based on placebo trial results.
Main Results:
- Caffeine improved power output and reduced TT completion time in both HP and LP groups compared to placebo.
- Low-performing cyclists experienced greater exercise-induced peripheral fatigue (reduction in Qtw,pot) with caffeine compared to placebo.
- High-performing cyclists did not show a significant difference in peripheral fatigue between caffeine and placebo conditions.
- No effect of caffeine on central fatigue (VA) was observed, though LP cyclists exhibited lower postexercise VA than HP cyclists.
Conclusions:
- Caffeine-induced performance benefits in a 4-km cycling TT may be associated with increased peripheral muscle fatigue in low-performing athletes.
- High-performing athletes appear to tolerate caffeine's effects on peripheral fatigue, suggesting an augmented tolerance to central fatigue during high-intensity exercise.
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