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Abnormal coupling of knee and hip moments during maximal exertions in persons with cerebral palsy
Author(s) -
Thelen Darryl D.,
Riewald Scott A.,
Asakawa Deanna S.,
Sanger Terence D.,
Delp Scott L.
Publication year - 2003
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.10357
Subject(s) - cerebral palsy , medicine , physical medicine and rehabilitation , physical therapy
The motions of lower‐limb extension, adduction, and internal rotation are frequently coupled in persons with cerebral palsy (CP) and are commonly referred to as an extension synergy. However, the underlying joint moments that give rise to these coupled motions are not well understood. We hypothesized that maximal voluntary exertions in a direction of one component of a synergy (e.g., hip extension) would result in the concurrent presence of other components of the synergy in subjects with CP but not in control subjects. To test this hypothesis, we measured three‐dimensional moments about the hip and knee as nine subjects with spastic CP and six control subjects performed maximal isometric exertions of the hip and knee flexors and extensors. During maximal hip extension exertions, control subjects simultaneously generated a knee flexion moment, whereas CP subjects generated a knee extension moment ( P < 0.05) and a larger hip internal rotation moment than did controls ( P < 0.05). During maximal knee extension exertions, control subjects generated a hip flexion moment, whereas CP subjects generated a hip extension moment ( P < 0.05). The patterns of joint moments generated by CP subjects are consistent with an extension synergy and may underlie the coupled motion patterns of the lower extremity in such persons. Muscle Nerve 27: 486–493, 2003