Acute leg-cycling exercise attenuates the H-reflex recorded in soleus but not flexor carpi radialis

Robert W. Motl, Rod K. Dishman

Research output: Contribution to journalArticlepeer-review


The amplitude of the Hoffman reflex (H-reflex) in the soleus muscle is attenuated after acute bouts of leg-cycling exercise. The attenuation has been interpreted as a "tranquilizing" effect of exercise controlled by the central nervous system and generalized beyond a single spinal segmental level. If so, the postexercise depression of the H-reflex should occur in both the soleus and the flexor carpi radialis (FCR) muscle, which is not actively involved during leg cycling. This experiment examined the effect of moderate-intensity cycling exercise on the H-reflex recorded in soleus and FCR among 16 men. The H-reflex was measured immediately before and 10 min after 30 min of either moderate-intensity leg cycling (60% VO2peak) or quiet rest. The acute bout of cycling exercise reduced the H-reflex in the soleus but not in the FCR. Thus, the attenuation of the H-reflex after leg cycling does not generalize beyond the spinal segmental level that modulates the involved locomotory muscles; it is likely the result of segmental processes associated with the repetitive stretching or activation of the soleus muscle.

Original languageEnglish (US)
Pages (from-to)609-614
Number of pages6
JournalMuscle and Nerve
Issue number5
StatePublished - Nov 2003


  • Acute exercise
  • Afferent mechanoreceptors
  • Hoffmann reflex
  • Segmental processes

ASJC Scopus subject areas

  • Physiology
  • Clinical Neurology
  • Cellular and Molecular Neuroscience
  • Physiology (medical)


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