THE EFFECTS OF BODY WEIGHT SUPPORT TREADMILL TRAINING ON AMBULATORY CAPACITY, BONE METABOLISM, AND BLOOD LIPID PROFILES IN PERSONS WITH SPINAL CORD INJURY

Abstract

Common sequelae ofchronic spinal cord injury (SCI) include ambulatory deficits, osteoporosis in sublesional bone, and dyslipidemia. Body weight support treadmill training (BWSTT) is recognized as an effective tool for ambulation retraining in persons with SCI. Until now, the ability ofBWSTT to modify bone metabolism and blood lipid and lipoprotein profiles has not been investigated. Given that this protocol has the potential to stress both the skeletal and cardiovascular systems, we proposed that in addition to improving ambulation, a BWSTT program would favorably modify bone metabolism and blood lipid and lipoprotein profiles in persons with SCI. To test these hypotheses, we completed a 3 month BWSTT study with 5 persons with chronic (19 months - 11 years post-injury), incomplete (ASIA C - D) SCI. The subjects trained 3X/week for a target duration of40 minutes/session. Levels of deoxypyridinoline, a urinary marker of bone resorption, and osteocalcin, a serum marker of bone tumover/formation, were determined pre- and post-training. Bone mineral density (BMD) ofthe whole body, lumbar spine, and hips was assessed at the same time intervals with DEXA. Plasma concentrations oftotal cholesterol (TC), high density lipoprotein cholesterol (HDL-C), TC/HDL-C, low density lipoprotein cholesterol (LDL-C), and very low density lipoprotein cholesterol (VLDL-C) were evaluated pre- and post-training. % BWS, treadmill velocity, ambulatory endurance, independent steps, and required assistance were recorded at each training session. iii Across the training period, all subjects experienced reductions in the amount of BWS and manual assistance that were required, and increases in independent stepping, treadmill velocity, and endurance. Ambulatory progress was related to the pre-training ASIA scores, with the greatest gains seen in those subjects with the highest residual motor capabilities. At the completion ofthe training program, urinary [deoxypyridinoline] was significantly increased (p<0.05) compared to pre-training. Serum [osteocalcin] and BMD were not significantly different pre-to post-training. With respect to lipid metabolism, only TC was significantly lower (p<0.05) post training. The response ofthe lipoprotein fractions to the BWSTT protocol was variable between subjects. The results ofthis study indicate that coincident with improving ambulation, BWSTT has the potential to increase bone remodelling in persons with chronic SCI. The effect ofthis protocol on lipid and lipoprotein profiles is uncertain.