We used biomechanical criteria to investigate efficiency of crutch gait. For this subject, lower extremity movements made during the gait cycle with the Hope crutches and the Standard crutches differed slightly. The Hope-crutch gait had a smaller range of motion at the hip and ankle joints. This discrepancy was significant enough to recommend the Hope crutches over the Standard crutches.
For nearly every measurement, the movement with the Hope crutches exhibited a smaller range of motion. We interpreted the smaller range of motion as representing a more stable gait; the two crutch-gait movements exhibited a nearly identical stride length (this rules out the possibility that greater stability in the Hope crutches was due to smaller stride length). Another difference between crutches was that the absolute angle of the trunk with the Hope crutches showed a more constant progression through the course of the gait cycle in comparison to the graph with the Standard crutches that contained more noise. From this we deduced that the Hope crutches produced a more fluid and controlled trunk movement. Previous findings have shown that a less contained and less efficient movement is associated with increased isometric and antagonistic muscle contractions to ensure stability of the body on the crutches (Thys et al., 1481). Since the Hope crutches exhibit this greater movement efficiency, less muscle force was needed to execute the crutch-gait with stability.
This study could be improved primarily by including more subjects, and preferably subjects that have been on crutches for a considerable amount of time before participating in the experiment. A larger subject pool would allow us to make more comparisons between the different gaits associated with the two different sets of crutches. It would also aid us in eliminating individual gait differences that different individuals have. By having a more "experienced" subject pool, this would help to keep data associated with learning curve effects negligible. Other experimental tests that would enhance this study would be to test for force and human work-energy consumption. Force could be tested with regards to loading of the upper body, while energy could be tested using oxygen consumption tests and EMG muscle readings. This type of test would require longer trial times. Lastly, examining the other joints that were marked might be also reveal more information to aid the study.
Andrews BJ, Granat MH, Heller BW, MacMahon J, Keting L, and Real S. (Jan.1994) Improved harness crutch to reduce upper limb effort in swing-through gait. Medical Engineering & Physics 16 (1), p. 15-18.
Thys H, Willems PA, and Saels P. (Nov.1996) Energy cost, mechanical work and muscular efficiency in swing-through gait with elbow crutches. Journal of Biomechanics 29 (11), p. 1473-1482.