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Neuromuscular fatigue after a ski skating marathon
Guillaume Y Millet1, Vincent Martin, Nicola A Maffiuletti
1INSERM/ERIT-M 0207 Motricité-Plasticité, Faculté des Sciences du Sport, Université de Bourgogne, BP 27 877-21078 Dijon, France.
Summary
Ski skating marathons cause slight, significant knee extensor strength loss without impacting central activation. This endurance event induces both potentiation and neuromuscular fatigue in trained skiers.
Area of Science:
- Sports Science
- Exercise Physiology
- Neuromuscular Physiology
Background:
- Marathon skiing is a demanding endurance event.
- Understanding neuromuscular fatigue is crucial for athlete performance and recovery.
Purpose of the Study:
- To characterize neuromuscular fatigue in knee extensor muscles following a marathon ski race.
- To assess changes in maximal voluntary contraction (MVC) and central activation.
Main Methods:
- 11 trained skiers underwent assessments before and after a marathon ski race.
- Maximal percutaneous electrical stimulations (single twitch, 0.5-s tetanus at 20 and 80 Hz) were applied to the femoral nerve.
- Maximal voluntary activation (% VA) was measured using superimposed twitches during MVC.
- EMG of the vastus lateralis muscle was recorded.
Main Results:
- Maximal voluntary strength (MVC) decreased by 8.4% (p < 0.005) post-race, while central activation (% VA) remained unchanged.
- EMG signal amplitude (RMS) and compound muscle action potential (PPA) decreased by ~30% (p < 0.01).
- Electrically evoked single twitches showed enhanced peak mechanical response and faster force development in the fatigued state.
Conclusions:
- Ski marathon alters knee extensor strength without affecting central activation.
- The event induces a combination of neuromuscular fatigue and potentiation.