The main purpose of the present study is to determine the relative contributions of central and peripheral fatigue during an ultra-endurance exercise.

For that purpose, 14 subjects running 24 hours on a treadmill will be compared with a control group being awake during the same period. Subjects who running will have electrically evoked forces on the muscles associated EMG activity, blood samples and muscle biopsy.

Inclusion Criteria:

• The subjects of the experimental group will be recruited among experienced ultra-runners . They all have run at least a 12 hour race or longer.
• The control group will be recruited among experienced ultra-runners . Age of control group will be age experimental group more or less 2 years.

Exclusion Criteria:

• The subjects will not be selected if:

  • they were injured in the 3 months before the experiment
  • they had a tendon or joint pathology that could impair strength measurements.
  • they participate to an other experiment at the same time