The Effect of Body Weight Support on Energy Expenditure in an Individual With High-Level Lower Extremity Amputation.

Background: High-level lower extremity amputation (HLLEA) has significant impact on an individual's ability to ambulate and maintain cardiovascular fitness for extended periods of time.

Objective: The purpose of this study was to evaluate whether body weight support (BWS) would improve energy efficiency in an individual with HLLEA to achieve appropriate target cardiovascular intensity for aerobic training.

Design: This was an exploratory single-subject study.

Methods: The participant was a 45-year-old woman, 4.5 years after left hip disarticulation secondary to necrotizing fasciitis with resultant organ failure and cardiomyopathy. She was wearing a well-fitted prosthesis and had a goal of ambulating in the community with less fatigue. Vital signs and expiratory gases were recorded, and oxygen uptake efficiency slope was calculated during treadmill walking at 0%, 20%, and 40% unweighting. An age-matched control completed 0% unweighting baseline testing.

Results: Under all conditions of treadmill walking, the participant's heart rate, blood pressure, and rate of perceived exertion consistently increased as speed and time increased. The participant's oxygen uptake efficiency slope was most efficient at 20% unweighting, and the economy of movement improved as the percentage of BWS increased, bringing values closer to the age-matched control. The participant reported only minimal pain immediately following 20% unweighting.

Limitations: The primary limitation of this study is generalizability of findings because of minimal information for comparing the effects of BWS on aerobic capacity in individuals with HLLEA. Additionally, the percentages of unweighting using BWS were extrapolated based on corollary preexisting research; thus, there were no set parameters defined for this specific population.

Conclusions: BWS allowed the participant to work more efficiently, which suggests that if used during an intervention, BWS might enable individuals with HLLEA to achieve recommended levels of training for aerobic conditioning. In future studies, it is recommended that 20% BWS be used at a speed that results in moderate-intensity exercise for individuals with HLLEA as determined by 50% to 70% of maximum heart rate for 20 to 30 minutes.