Biomechanical determinants of top running speeds in para-athletes with unilateral transfemoral amputation

Background: An increased understanding of biomechanical determinants that influence the sprint performance of para-athletes with a unilateral transfemoral amputation will provide us with a basis for better evaluating athletes' sprint performance and would be expected to aid in the development of more effective training methods and running-specific prosthesis selection guidelines. Objectives: The aim of this study was to investigate the relative contributions of mechanical determinants to the top running speeds of para-athletes with unilateral transfemoral amputation wearing a running-specific prosthesis. Study design: Observational study within the subject. Methods: Nine para-athletes with unilateral transfemoral amputation wearing a running-specific prosthesis were recruited in this study. They were asked to run at their respective constant top speeds on an instrumented treadmill. From the ground reaction force and spatiotemporal parameters, three mechanical variables-step frequency, mass-specific averaged vertical ground-reaction force, and contact length-were determined for both the affected and unaffected limbs. Results: Stepwise regression analysis showed that the contact length of the affected limb was significant and an independent factor of top running speed (β = 0.760, P < 0.05), with a coefficient of determination (R2) of 0.577 (P < 0.05), whereas the other variables were not associated. Conclusion: These results suggest that prosthetic components and alignment are crucial to determining the maximal sprinting performance in uTFA.