Human hypoglossal motor unit activities in exercise

Clinton E. Walls, Christopher M. Laine, Ian J. Kidder, E. Fiona Bailey

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


The genioglossus (GG) muscle is considered the principal protruder muscle of the tongue that dilates and stiffens the pharyngeal airway. We recorded whole muscle and single motor unit (MU) activities in healthy adults performing progressive intensity exercise on a cycle ergometer. Tungsten microelectrodes were inserted percutaneously into the GG of 11 subjects (20-40 years) to record electromyographic (EMG) activities and pulmonary ventilation (VI) at rest and at workload increments up to 300 W. Increases in respiratory drive were associated with increases in VI, mean inspiratory flow (Vt/Ti) and tonic and phasic components of the GG EMG activity. In contrast, individual MUs typically showed expiration-related decreases in firing as exercise intensity increased. We suggest the decrease in MU activity may occur secondary to afferent feedback from lungs/chest wall and that compensation for more negative inspiratory airway pressures generated during heavy exercise occurs primarily via recruitment of previously silent MUs.

Original languageEnglish (US)
Pages (from-to)3579-3590
Number of pages12
JournalJournal of Physiology
Issue number14
StatePublished - Jul 2013

ASJC Scopus subject areas

  • Physiology


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