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Hip joint position modulates volitional knee extensor muscle activity after stroke
Author(s) -
Lewek Michael D.,
Schmit Brian D.,
Hornby T. George,
Dhaher Yasin Y.
Publication year - 2006
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.20663
Subject(s) - physical medicine and rehabilitation , isometric exercise , medicine , supine position , proprioception , trunk , stroke (engine) , reflex , sitting , vestibular system , electromyography , physical therapy , mechanical engineering , ecology , pathology , engineering , biology , radiology
Evidence from animal and human models has demonstrated the importance of hip proprioceptors and vestibular inputs in modulating lower‐extremity muscle activity through reflex pathways. Comprehension of the role of these sensory inputs following stroke may be important in understanding pathological muscle activity during functional activities. We therefore examined the influence of both hip and head/trunk position on volitional quadriceps activity in chronic stroke and control subjects. With the knee held at 60°, maximal voluntary isometric quadriceps contractions were elicited with trunk orientation (head position) and hip angle systematically positioned at 0°, 45°, and 90°. Integrated electromyographic activity from the quadriceps was compared between groups and conditions. Vasti activity in the stroke group was greater in a seated upright posture (hip flexed) than supine (hip neutral). Controlling for vestibular input, the stroke group demonstrated greater quadriceps activity (VL and RF) with a neutral hip compared to flexion. Such findings may have implications for understanding inappropriate muscle activity during walking after stroke, as hip extension occurs immediately prior to toe off, when inappropriate quadriceps activity is commonly observed. Muscle Nerve, 2006