Electromyographic analysis of postural responses during standing leg flexion in adults with hemiparesis

• Published in: Electroencephalography and clinical neurophysiology Vol. 105; no. 2; pp. 149 - 155
• Main Authors: Hedman, L.D., Rogers, M.W., Pai, Y.-C., Hanke, T.A.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ireland Ltd 01.04.1997; Elsevier Science
• Subjects: Adult; Aged; Balance control; Biological and medical sciences; Electromyography; Female; Hemiplegia - physiopathology; Hip abductor muscles; Human stance; Humans; Leg; Male; Medical sciences; Middle Aged; Muscle, Skeletal - physiopathology; Neurology; Postural adjustments; Posture - physiology; Reference Values; Rehabilitation strategies; Space life sciences; Stroke; Time Factors; Vascular diseases and vascular malformations of the nervous system; Balance control; Postural adjustments; Stroke; Hip abductor muscles; Human stance; Rehabilitation strategies; Human; Hemiparesis; Nervous system diseases; Motor system disorder; Lower limb; Cardiovascular disease; Striated muscle; Cerebral disorder; Posture; Vascular disease; Electrodiagnosis; Central nervous system disease; Electromyography; Orthostatism; Neurological disorder; Postural fitting; Cerebrovascular disease
• ISSN: 0924-980X; 0013-4694; 1872-7093
• DOI: 10.1016/S0924-980X(96)95134-6

The purpose of this study was to examine muscle activation patterns during standing single leg flexion in adults with hemiparesis. Specifically, the electromyographic activation patterns of the flexing limb biceps femoris and gluteus medius, and the stance limb gluteus medius muscles were analyzed as a function of whether the muscles were paretic or not. Delayed activation of the affected flexing side gluteus medius, as compared with unaffected flexing side gluteus medius, resulted in it being activated simultaneous with the flexing biceps femoris rather than preceding it as was previously found in healthy subjects. This suggests a temporal change in the sequential mode of coordination of the postural and intended components of the task. In addition, the magnitude of the electromyographic integrals of both the affected and unaffected flexing side gluteus medius in the early propulsive phase of the task was significantly reduced in comparison with healthy subjects. These alterations can be attributed to spatial alterations in the sequential form of organization or to a shift to a different mode of neural control in order to perform a relatively novel task. These results suggest a potential adaptive capacity in these individuals.