Locomotor Training and Factors Associated with Blood Glucose Regulation After Spinal Cord Injury

Background: Individuals with spinal cord injury (SCI) have increased rates of glucose intolerance, insulin insensitivity, and type II diabetes caused mainly by the deconditioning of paralyzed muscle. The purpose of this systematic review was to determine the effectiveness of locomotor training in individuals with SCI on blood glucose control. Methods: We searched studies on locomotor training for individuals with SCI with outcomes of glucose, insulin, or outcomes that could change glucose handling (i.e. increases in muscle mass, shifts in muscle fiber type composition, changes in transport proteins, or enzymes involved in glucose metabolism) in PubMed and EMBASE. Results: Eleven studies (10 with incomplete SCI; 1 with complete SCI) were included in our review. Locomotor training included body weight supported treadmill training (BWSTT) with manual or robotic assistance, with and without functional electrical stimulation (FES), or involved FES-assisted over ground training. Six months of locomotor training in individuals with SCI resulted in significant decreases in glucose (15%) and insulin (33%) areas under the curve during oral glucose tolerance tests. Two to twelve months of locomotor training reversed some of the muscle atrophy - with muscle being the site of most glucose consumption, this is important for glucose control. Training also increased capacity for glucose storage, enzymes involved in glucose phosphorylation (hexokinase) and oxidation (citrate synthase), and glucose transport proteins (GLUT-4). Fiber type composition shifted to a slower fiber type, which favors glucose handling. There were no effects on fat mass. Conclusion: Locomotor training in individuals with SCI (generally an incomplete injury) increases capacity to handle glucose and results in muscular changes that should reduce the risk of type II diabetes.