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Corticospinal adaptations and strength maintenance in the immobilized arm following 3 weeks unilateral strength training
Author(s) -
Pearce A. J.,
Hendy A.,
Bowen W. A.,
Kidgell D. J.
Publication year - 2013
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/j.1600-0838.2012.01453.x
Subject(s) - transcranial magnetic stimulation , physical medicine and rehabilitation , medicine , strength training , isometric exercise , corticospinal tract , leg muscle , physical therapy , muscle strength , stimulation , magnetic resonance imaging , diffusion mri , radiology
Cross‐education strength training has being shown to retain strength and muscle thickness in the immobilized contralateral limb. Corticospinal mechanisms have been proposed to underpin this phenomenon; however, no transcranial magnetic stimulation ( TMS ) data has yet been presented. This study used TMS to measure corticospinal responses following 3 weeks of unilateral arm training on the contralateral, immobilize arm. Participants ( n = 28) were randomly divided into either immobilized strength training (Immob + train) immobilized no training (Immob) or control. Participants in the immobilized groups had their nondominant arm rested in a sling, 15 h/day for 3 weeks. The Immob + train group completed unilateral arm curl strength training, while the Immob and control groups did not undertake training. All participants were tested for corticospinal excitability, strength, and muscle thickness of both arms. Immobilization resulted in a group x time significant reduction in strength, muscle thickness and corticospinal excitability for the untrained limb of the Immob group. Conversely, no significant change in strength, muscle thickness, or corticospinal excitability occurred in the untrained limb of the Immob + train group. These results provide the first evidence of corticospinal mechanisms, assessed by TMS , underpinning the use of unilateral strength training to retain strength and muscle thickness following immobilization of the contralateral limb.