Effect of 15% body weight support on exercise capacity of adults without impairments

Abstract

Background and Purpose. External support of body weight, a technique used for the gait training of patients with neurologic conditions, may also be beneficial for tests of exercise capacity in people whose impairments in motor function and balance have traditionally precluded such testing. The purpose of this study was to investigate the effect of using external support of 15% of body mass during treadmill exercise testing of adults without impairments. Subjects and Methods. Seven men and 8 women (mean age=55.2 years, SD=11.3, range=43-82) performed 3 treadmill tests with random assignment of testing condition: (1) no body weight support (BWS) - standard test, (2) 0% BWS - harness in place but no use of external support, and (3) 15% BWS - use of external support for 15% of body mass. Expired gas was analyzed to determine oxygen uptake, carbon dioxide production, minute ventilation, tidal volume, heart rate, and respiratory exchange ratio. Results. Use of external support for 15% of body mass did not affect the end-expiratory gas exchange variables, although the time to achieve peak values was lengthened. Maximal tidal volume was lower in the 15% BWS test, but maximal minute ventilation was not different. Discussion and Conclusion. Because 15% BWS did not affect the exercise capacity of adults without known impairments, future study of its application to testing of patients with neurologic injuries is warranted. [MacKay-Lyons M, Makrides L, Speth S. Effect of 15% body weight support on exercise capacity of adults without impairments.