Abstract: Skeletal muscle contractile properties are determined by their myosin heavy chain (MHC) expression profiles partly. Spinal cord injury induced the adaptation change in MHC isoform mRNAs and protein expression of skeletal muscle below the injured level, leading to the increased expression of fast and decreased expression of slow MHC isoforms. The adaptations in the MHC-mRNAs preceded the changes in proteins. The degree and velocity of MHC isoform adaptation were dependent on differenrt muscle and animal species. Short-term training could not induce the significant change of the transformation of MHC isoform, whereas long-term stepping training which emphasized load bearing could attenuate the MHC shift from slow toward faster isoforms.

Key words: spinal cord injury, muscle atrophy, myosin heavy chain, training, review