COMPARISON OF TREADMILL EXERCISE TESTING PROTOCOLS FOR WHEELCHAIR USERS

The reduced early mortality and the increased life span of persons wit h spinal cord injury (SCI) and other chronically disabling conditions which result in loss of use of the legs places them at increased risk of coronary heart disease, diabetes, and hypertension. Exercise testin g in this population is becoming more common, but there is a need for assessment of protocols in order to determine the best method to elici t a maximal response in a reasonable time without endangering the pati ent. Three wheelchair treadmill protocols were compared in seven men w ith paraplegia aged 21-44 years (five SCI, two post-polio). Subjects r epeated each protocol to estimate reliability. Protocol G consisted of increasing treadmill grade at a constant speed (4.8 km.h-1); in proto col S, the speed was increased at a constant grade (0%), and in protoc ol C, speed and grade were increased. Two-minute stages were used in a ll protocols. Peak oxygen uptake [VO2max; mean (SD): 23.6 (5.8) ml . k g-1. min-1; 1.66 (0.37) 1 . min-1], VCO2 production [1.98 (0.46) 1.min -1], ventilation volume [83.0 (25.6) 1 . min-1], respiratory exchange ratio [1.2 (0.12)], and heart rate [173 (18)] were determined. Over al l trials none of the variables was significantly different among the t hree protocols, but all were highest in C and lowest in S. Reliability coefficients for absolute and relative VO2max ranged from 0.76 and 0. 81 in G to 0.95 and 0.98 in C (all P<0.05). These data suggest that an incremental treadmill test similar to the C protocol may be the optim al method to use when evaluating the exercise capacity of wheelchair u sers.