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

PURPOSE: The use of body weight support treadmill (BWST) training for rehabilitation of patients with brain injuries, as well as musculoskeletal and neuromuscular impairments, is an emerging clinical treatment method. Because of the limited evidence of physiological stress of BWST training, the purpose of this study was to describe the metabolic and cardiovascular response to varying levels of BWST walking in healthy adult subjects. METHODS: A total of 21 subjects (10 females; 34+6.7 yr; 74.6+14.3 kg; 170.8+6.9 cm; 26.1+5.3 kg/m) provided their informed consent to participate in three 5-minute walking trials at a self-selected treadmill speed, with body weight support (BWS) of 0, 15, and 30%. Test order was randomized for each subject. Subjects rested for a minimum of 5 minutes between each trial, and did not begin a subsequent trial until HR was verified to be < 5 bpm of HR rest. Mean HR (12-lead ECG), BP (auscultation), oxygen uptake (continuous indirect calorimetry), and RPE (Borg ratio scale) 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 (SPSS ver. 24, New York, NY). RESULTS: At rest, HR was 78.2+11.5 bp and BP was 121.2+7.9 / 76.9+8.0 mmHg. Mean walking speed of subjects was 64.2 m/min. HR and systolic BP significantly (p<0.05) increased from rest to exercise at all BWS levels, 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 METs. CONCLUSIONS: Metabolic and cardiovascular responses to treadmill walking at 3 levels of BWS (0, 15, 30%) were similar in apparently healthy adult subjects.