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Muscle activation varies with contraction mode in human spinal cord injury
Author(s) -
Kim Hyosub E.,
Thompson Christopher K.,
Hornby T. George
Publication year - 2015
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.24285
Subject(s) - isometric exercise , concentric , eccentric , medicine , electromyography , physical medicine and rehabilitation , spinal cord injury , muscle contraction , contraction (grammar) , physical therapy , spinal cord , cardiology , anatomy , mathematics , physics , geometry , quantum mechanics , psychiatry
: To better understand volitional force generation after chronic incomplete spinal cord injury (SCI), we examined muscle activation during single and repeated isometric, concentric, and eccentric knee extensor (KE) maximal voluntary contractions (MVCs). Methods : Torque and electromyographic (EMG) activity were recorded during single and repeated isometric and dynamic KE MVCs in 11 SCI subjects. Central activation ratios (CARs) were calculated for all contraction modes in SCI subjects and 11 healthy controls. Results : SCI subjects generated greater torque, KE EMG, and CARs during single eccentric vs. isometric and concentric MVCs (all P < 0.05). Torque and EMG remained similar during repeated eccentric MVCs; however, both increased during repeated isometric (>25%) and concentric (>30%) MVCs. Conclusions : SCI subjects demonstrated greater muscle activation during eccentric MVCs vs. isometric and concentric MVCs. This pattern of activation contrasts with the decreased eccentric activation demonstrated by healthy controls. Such information may aid development of novel rehabilitation interventions. Muscle Nerve 51 : 235–245, 2015