Metabolic and Cardiovascular Effects of Body Weight Support Treadmill Walking in Healthy Adults

Purpose: Limited and conflicting evidence exists regarding the metabolic and cardiovascular responses of body weight support (BWS) treadmill training (BWSTT). The purpose of this study was to describe the metabolic (as assessed by oxygen uptake) and cardiovascular responses to varying levels of BWSTT in healthy adult subjects. Methods: Twenty-one subjects (10 females; 34.5 [6.7] yr.; 74.6 [14.3] kg; 170.8 [6.9] cm; 26.1 [5.3] kg/m2) provided their informed consent to participate in 3 5-minute walking trials at a self-selected treadmill speed, with BWS of 0%, 15%, and 30%. Test order was randomized. Subjects rested at least 5 minutes between trials and did not begin another trial until the heart rate (HR) was <5 bpm of HR rest. Mean HR, blood pressure (BP), oxygen uptake, and rating of perceived exertion (RPE) were determined from the last 3 minutes of each trial. Mean values for all variables were assessed for difference between trials using repeated-measures analysis of variance. Results: At rest, HR was 78.2 (11.5) bpm and BP was 121.2 (7.9)/76.9 (8.0) mm Hg. Mean walking speed of subjects was 65.4 m/min. Heart rate and systolic BP significantly (P < .05) increased from rest with exercise at each level of BWS, with no significant difference in diastolic BP seen from rest to exercise at all BWS levels. There was no statistical difference among levels of BWS for HR, BP, RPE, oxygen uptake, respiratory exchange ratio, respiratory rate, tidal volume, and metabolic equivalent of tasks. Conclusions: Healthy adult subjects walking at self-selected speeds at BWS levels up to 30% fail to demonstrate significant changes in metabolic and cardiovascular responses.