Behaviour of the motoneurone pool in a fatiguing submaximal contraction

• DOI: 10.1113/jphysiol.2011.207191
• Publication Date: 2011-05-24T02:29:13Z
• Authors: Chris J. McNeil; Sabine Giesebrecht; Simon C. Gandevia; Janet L. Taylor
• Keywords: Adult; Male; Motor Neurons; Electromyography; Motor Cortex; Evoked Potentials, Motor; Transcranial Magnetic Stimulation; Electric Stimulation; 12. Responsible consumption; 03 medical and health sciences; 0302 clinical medicine; Elbow Joint; Muscle Fatigue; Humans; Female; Muscle, Skeletal; Muscle Contraction

Non‐technical summary During a sustained maximal contraction, motoneurones rapidly become less responsive to input. This decrease is ameliorated by a high level of voluntary drive from the cortex. Here, we tested whether the excitability of motor cortical neurones or spinal motoneurones is suppressed during fatigue produced by a sustained submaximal contraction in which only some of the motoneurones are active. We found that motoneurone responses were gradually suppressed as fatigue developed. The results suggest that only the active motoneurones were affected and the decreased responsiveness was less when voluntary drive was present. In contrast, the excitability of the motor cortex appeared unaffected.