Decreased excitability of motor axons contributes substantially to contraction fatigability during neuromuscular electrical stimulation.

These data files accompany a paper submitted for publication to Applied Physiology, Nutrition, and Metabolism. Neuromuscular electrical stimulation, or NMES, is a technique used for rehabilitation, maintenance of physical activity, and functional neuroprosthetic applications (e.g. to compensate for foot drop). The contraction of the muscles intermittently activated by NMES may start strong and functional but rapidly weaken; a process we refer to as contraction fatigability. Historically we along with our peers have considered that the muscle itself and the recruitment of motor units in the muscle during NMES are the primary mechanisms underlying the rate that contraction fatigability develops. We demonstrate in this paper that the excitability of the motor axons innervating the muscle are equally, if not more, important than the muscle properties during these types of contractions.