The present study investigated the relative contribution of the cortical and spinal mechanisms for post-exercise excitability changes in human motoneurons. Seven healthy right-handed adults with no known neuromuscular disabilities performed an isometric voluntary wrist flexion at submaximum continuous exertion. After the subjects continued muscle contraction until volitional fatigue, the H-reflexes induced by an electric stimulation and motor evoked potentials (MEPs) induced by a transcranial magnetic stimulation (TMS) from a flexor carpi radialis (FCR) muscle were recorded 7 times every 20 s. The H-reflex was used to assess excitability changes at the spinal level, and the MEP was used to study excitability changes at the cortical level. H-reflexes showed a depression (30% of control value) soon after the cessation of wrist flexion and recovered with time thereafter. On the other hand, an early (short latency) MEP showed facilitation immediately after the cessation of wrist flexion (50% of control value) and thereafter decreased. A possible mechanism for the contradictory results of the 2 tests, in spite of focusing on the same motoneuron pool, might be the different test potential sizes between them. In addition, a late (long latency) MEP response appeared with increasing exercise. With regard to the occurrence of late MEP response, a central mechanism may be proposed to explain the origin—that is, neural pathways with a high threshold that do not participate under normal circumstances might respond to an emergency level of muscle exercise, probably reflecting central effects of fatigue.
Takashi Kato, Yusaku Takeda, Toshio Tsuji and Tatsuya Kasai
Lee N. Burkett, Jack Chisum, Jack Pierce, Kent Pomeroy, Jim Fisher and Margie Martin
Twenty spinal-cord-injured subjects (4 quadriplegics and 16 paraplegics) were maximally stress tested on the Arizona State University wheelchair ergometer. Physiological data for each individual were collected as follows: (a) blood flow in the left leg by a photoelectric plethysmograph before exercise, during exercise, and postexercise, and (b) blood lactates before exercise and post-exercise. Eleven subjects had increased leg blood flow and vasodilation during exercise, but vasoconstriction postexercise. The lactate readings, in comparison to able-bodied individuals, were higher at rest but lower at maximal exercise.
Linda Corbally, Mick Wilkinson and Melissa A. Fothergill
intervention group. Lower salivary cortisol has been previously reported in elite shooters ( John, Verma, & Khanna, 2011 ) and both results agree with findings in healthy non-athletic populations ( Sanada et al., 2016 ). In summary, regular mindfulness practice could serve to reduce post-exercise inflammation
Renee Engeln, Margaret Shavlik and Colleen Daly
no effect of the presence of mirrors, but for conditions in which the instructor wore loose-fitting clothing and emphasized health outcomes, students reported higher positive affect post-exercise. A different study ( O’Hara et al., 2014 ) found mixed results regarding the effect of instructor