Body-weight-support treadmill training improves blood glucose regulation in persons with incomplete spinal cord injury.
The impact of a 6-mo body-weight-supported treadmill training program on glucose homeostasis and muscle metabolic characteristics was investigated. Nine individuals (31 +/- 3 yr, 8.1 +/- 2.5 yr postinjury; means +/- SE) with incomplete spinal cord injury trained three times weekly for a total of 6 mo. Training session duration and intensity (velocity) increased by 54 +/- 10% (P < 0.01) and 135 +/- 20%, respectively. Muscle biopsies and a modified glucose tolerance test (100 g glucose with [U-(13)C]glucose) were performed before (Pre) and after training (Post). Training resulted in a reduction in area under the curve of glucose x time (-15 +/- 4%) and insulin x time (-33 +/- 8%; both P < 0.05). Oxidation of exogenous (ingested) glucose increased as a result of training (Pre = 4.4 +/- 0.7 g/h, Post = 7.4 +/- 0.6 g/h; P < 0.05), as did oxidation of endogenous (liver) glucose (Pre = 3.8 +/- 0.3 g/h, Post = 5.2 +/- 0.3 g/h; P < 0.05). Training resulted in increased muscle glycogen (80 +/- 23%; P < 0.05) and GLUT-4 content and hexokinase II enzyme activity (126 +/- 34 and 49 +/- 4%, respectively, both P < 0.01). Resting muscle phosphocreatine content also increased after training (Pre = 62.1 +/- 4.3, Post = 78.7 +/- 3.8, both mmol/kg dry wt and P < 0.05). Six months of thrice-weekly body-weight-supported treadmill training in persons with an incomplete spinal cord injury improved blood glucose regulation by increasing oxidation and storage of an oral glucose load. Increases in the capacity for transport and phosphorylation glucose in skeletal muscle likely play a role in these adaptations.
Phillips
Stuart M
SM
Department of Kinesiology, Exercise and Metabolism Research Group, Centre for Health Promotion and Rehabilitation, McMaster University, 1280 Main St. West, Hamilton, ON, Canada L8S 4K1. phillis@mcmaster.ca
Stewart
Brian G
BG
Mahoney
Douglas J
DJ
Hicks
Audrey L
AL
McCartney
Neil
N
Tang
Jason E
JE
Wilkinson
Sarah B
SB
Armstrong
David
D
Tarnopolsky
Mark A
MA
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D001823:Body Composition; D001944:Breath Tests; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000378:metabolism* / Q000628:therapy*; D005080:Exercise Test; D005081:Exercise Therapy; D051275:Glucose Transporter Type 4; D006593:Hexokinase / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000097:blood; D009004:Monosaccharide Transport Proteins / Q000378:metabolism; D009124:Muscle Proteins / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism; D010084:Oxidation-Reduction; D010766:Phosphorylation; D013119:Spinal Cord Injuries / Q000150:complications / Q000378:metabolism* / Q000628:therapy*
D001786:Blood Glucose; D051275:Glucose Transporter Type 4; D007328:Insulin; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; C495692:SLC2A4 protein, human; D006593:Hexokinase