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Central excitability contributes to supramaximal volitional contractions in human incomplete spinal cord injury
Author(s) -
Thompson Christopher K.,
Lewek Michael D.,
Jayaraman Arun,
Hornby T. George
Publication year - 2011
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2011.212233
Subject(s) - spinal cord injury , physical medicine and rehabilitation , functional electrical stimulation , medicine , reflex , spinal cord , weakness , stimulation , muscle fatigue , neuroscience , electromyography , psychology , anesthesia , anatomy
Non‐technical summary Individuals with a motor incomplete spinal cord injury (SCI) present clinically with partial control of muscles below the site of the injury, but experience profound weakness which can limit the ability to perform functional tasks such as walking. Interestingly, when individuals with an incomplete SCI are asked to maximally and repeatedly contract their quadriceps muscles, they demonstrate an increase in the peak force generated; individuals without SCI experience a decline in force, or ‘fatigue’. Following these repeated maximal efforts, reflex responses to electrical stimulation over the quadriceps muscle elicited amplified and prolonged, involuntary motor activity. Such responses were not observed prior to the maximal contractions, and were not observed in neurologically intact subjects. This finding suggests that increases in spinal excitability following these maximal efforts may enhance force generating capacity, and provides insight into possible novel therapeutic interventions to restore function following SCI.