Metabolic evaluation of the criteria used to fit elbow crutches by measurement of oxygen consumption

Abstract

Objective: To investigate if elbow crutches fitted using conventional guidelines are the most metabolically efficient. Design: Repeated measure connivance sample using crutch length as the independent variable. Setting: A university exercise physiology laboratory. Other Participant: Connivance sample of 10 students free from cardiovascular disease, with previous experience in crutch ambulation, and between the heights of 160 and 175cm. Four potential subjects refused to participate in the study. Interventions: Crutch length was adjusted using conventional guidelines, and to lengths 2.5cm above and below this setting. Oxygen consumption was measured using indirect open-circuit spirometry during the final 3 minutes of ambulation using self-selected walking speeds. Main Outcome Measure: Crutches adjusted to the convention setting are not the most efficient in terms of metabolic energy expenditure. Results: A significant reduction in oxygen rate ( p = .012), oxygen cost ( p = .010), and respiratory exchange ratio ( p = .009) were observed when comparing crutches adjusted to −2.5cm of the standard height with coinventional crutch height. Crutches adjusted 2.5cm above the standard height also required less energy, but these values failed to reach any statistical significance ( p > .05). Conclusion: The importance of fitting crutches to the correct length using conventional guidelines has not been substantiated in this study. Clinically, there should be a move away from adherence to crutch-fitting criteria and more incorporation of patient feedback to fit crutches to the optimal height. Future research should evaluate the reliability of practical clinical measures such as heart rate and perceived exertion to fit crutches to the optimal height.