Résumé
Workers experience recurrent episodes of fatigue during physical work that requires effort from the upper extremity. Although the etiology of fatigue is not well understood, the general agreement is that muscular work causes abnormal increases in intramuscular pressure, thus impairing local tissue perfusion causing ischemia and fatigue. Low-force contractions result in impaired oxidative metabolism, causing muscle fatigue that may be a precursor to muscle disorders. There is evidence that near-infrared spectroscopy (NIRS)-derived signals can be used to evaluate oxidative metabolism in working muscles. Muscle oxygenation status during upper extremity work could help provide insight into the pathophysiological mechanisms behind work-related muscle fatigue. This paper reviews the role of NIRS-derived measures in characterizing muscle performance of the upper body in the workplace and in evaluating fatigue and injury prevention.
In industry, there is a need for methodologies that provide reliable physiological measures under field conditions. NIRS offers portability and ease of operation, and provides an estimate of muscular metabolism under conditions where invasive methods are not possible.