Biomechanics of Running Using Different Stiffness of Carbon Fiber Foot Prosthesis in Transtibial Amputee Athletes

Abstract

Fitting the appropriate prosthesis to a transtibial amputee athlete is a complex process that involves repeated modification and alteration to ensure the appropriate size, residual limb/prosthesis interface, carbon fiber foot stiffness (CFFS) and athletic performance. A less than optimal fit may attenuate performance and lead to injury. PURPOSE: The purpose of this study was to evaluate biomechanical changes of running resulting from a range of CFFS stiffness. METHODS: 12 transtibial amputee runners (run experience of 6 yrs) volunteered to perform steady state bouts of exercise at 107, 134, 161, and 188 m/min using five randomly assigned CFFS including their normal stiffness, plus two of greater CFFS and two CFFS below their personal standard. All athletes were fitted by the same prosthetist and changes in carbon fiber feet were performed by a trained technician. Biomechanical analysis included video filming and analysis with Dartfish software. RESULTS: Statistical analysis revealed a significant correlation between body mass and CFFS (.754), and VO2 and run speed (.790). At speeds of 107, 134, 161, and 188 m/min, there were no significant differences among stride length (91, 91.6, 92.1, and 93.3 cm), % CFF compression (24.5, 22.8, 19.3, and 19.7%), and flight time (.113,.102,.102, and.098 sec), respectively. CONCLUSION: The small heterogeneous sample did not reveal significant difference among the CFFS, however individual differences may be important for comfort, performance, and reduced injury potential.