Validation of the virtual elevation field test method when assessing the aerodynamics of para-cyclists with a uni-lateral trans-tibial amputation

Abstract

Lower-limb amputees typically require some form of prosthetic limb to ride a bicycle for recreation or when competing. At elite-level racing speeds, aerodynamic drag can represent the majority of the resistance acting against a cyclists’ forward motion. As a result, the reduction of such resistance is beneficial to an amputee whereby the form and function of the prosthetic limb can be optimized through engineering. To measure the performance of such limbs, field testing provides a cost-effective and context-specific method of aerodynamic drag measurement. However, few methods have been formally validated and none have been applied to amputees with lower-limb amputations. In this paper, an elite level para-cyclist wore two different prosthetic limb designs and had their total aerodynamic drag of a wind tunnel reference method statistically correlated against a velodrome-based virtual elevation field test method. The calculated coefficient of variation was in the range of 0.7–0.9% for the wind tunnel method and 2–3% for the virtual elevation method. A 0.03 m² difference was identified in the absolute values recorded between the two methods. Ultimately, both methods exhibited high levels of precision, yet relative results to each other. The virtual elevation method is proposed as a suitable technique to assess the aerodynamic drag of amputee para-cyclists.

Implications for rehabilitation

• This assessment method will provide practitioners a reliable means of assessing the impact of changes made to prosthetics design for cyclists with limb absence.

• The proposed method offers a low cost and geographically accessible solution compared to others proposed in the past.

• This assessment method has significant potential for impact among prosthetic limb users looking to improve their cycling performance whereas previous attention in this field has been extremely limited.

Keywords:

• Prosthesis
• amputation
• cycling
• aerodynamics

Acknowledgements

The authors wish to thank the cyclist that participated in this study. The authors would also like to thank Pace Rehabilitation Ltd. for the manufacture and supply of the prosthetic limbs used for this study.

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.