Professor, Human Performance Lab
Ph.D. (Doctor of Philosophy)
M.A. (Master of Arts)
M.Sc. (Master of Science)
Research and teaching
- Spinal Cord / Nerve Injury & Pain
Fatigue is one of the most common and distressing side effects experienced by patients in various diseases. Neuromuscular fatigue is an exercise-related decrease in the maximal voluntary force or power of a muscle or muscle group associated with an increase in the perceived effort necessary to exert the desired force. Fatigue can originate at several potential sites that are usually classified as being proximal (central fatigue) or distal (peripheral fatigue) to the neuromuscular junction. Central fatigue is an alteration within the central nervous system leading to a de-recruitment of motor units and/or a decrease of the discharge frequency below the frequency of tetanic fusion, both factors leading to force or power decline. To assess central fatigue, a combination of magnetic stimulation of the motor cortex (MEP and TMS voluntary activation), transmastoid and nerve electrical stimulation must be used but many methodological problems exist with those techniques which preclude their use with patients. My work deal with the measurement of central fatigue in two populations: athletes doing extremes sports (ultra-endurance exercises or hypoxia) and patients.
In this latter, I aim at developing techniques that associate EMG and force responses to voluntary and electrically/magnetically evoked contractions and that are suitable in ‘fragile’ populations. For example, we recently validated the QIF test. Its main advantage is that using femoral nerve magnetic stimulation at each stage on relaxed muscles limits the influence of subject's cooperation and motivation. It is important since it has been shown that subjects’ motivation and their capacity to withstand pain is a key factor in task failure. This can, at least partly, explain why patients exhibit a wider variability in endurance time than healthy subjects.