Define central fatigue

Central fatigue is the progressive reduction in voluntary activation of muscle caused by processes occurring proximal to the neuromuscular junction. Accounts for up to two-thirds (66%) of the loss of force caused by a sustained weak contraction. Can be assessed with the interpolated twitch technique which involves stimulating the muscle or brain during a maximal voluntary contraction. Superimposed twitch during a maximal contraction implies that voluntary activation of muscle is less than maximal.