The Biomechanics of Cycling with a Transtibial Amputation

Abstract

People with amputations may find cycling advantageous for exercise, transportation and rehabilitation. The reciprocal nature of stationary cycling also makes it a viable model for research in motor control because the body is supported by the saddle allowing the researcher to focus on the cyclic movement of the legs without the confounding variable of balance. The purpose of this article is to provide an overview of the cycling task in intact cyclists and relate this information to understanding the challenges faced by cyclists with transtibial amputations (CTA). Ongoing research into the biomechanics of CTAs will be summarized to expose the differences between intact and CTA cycling mechanics, asymmetries between limbs of CTAs as well as neuromuscular adaptation following amputation. The article will include recommendations for prosthetic design and modification of the bicycle to improve cycling performance for CTA at all experience levels.

Sport prostheses and prosthetic adaptations for the upper and lower limb amputees

“…If the prospective cyclist wishes to use a regular prosthesis for cycling, it may be helpful to attach the prosthetic foot to the pedal using a cleat. 9 Attaching a cleat to the prosthetic foot increases the effective length of the cycling prosthesis. Therefore, the effective length of the prosthesis to be used for cycling (racing) should be measured from the centre of the knee to the centreline of the cleat, and not to the heel, which is the case with a regular walking prosthesis.…”

“…Additionally, the pedal should be laterally offset to allow for easier mounting and dismounting from the bicycle. 9 If a leg prosthesis used for cycling is fitted with an energy-storing foot, the cyclist may experience a loss of propulsive power, especially while pushing the pedal with the amputated limb. 9 This problem becomes more noticeable with an increasing cycling frequency.…”

“…9 If a leg prosthesis used for cycling is fitted with an energy-storing foot, the cyclist may experience a loss of propulsive power, especially while pushing the pedal with the amputated limb. 9 This problem becomes more noticeable with an increasing cycling frequency. Consequently, a racing cyclist may feel the need to remove the foot altogether and connect the pedal directly to the prosthetic pylon using a toe cleat.…”

“…Consequently, a racing cyclist may feel the need to remove the foot altogether and connect the pedal directly to the prosthetic pylon using a toe cleat. 9 …”

Effectiveness of force production in persons with unilateral transtibial amputation during cycling

“…These individuals must now adapt to structural and physiological changes related to the amputation and interact with their environment via a prosthetic limb on one side and via an intact limb on the other. 1 Changes that occur after amputation include: the sound limb becomes the dominate limb for locomotion [2][3][4][5][6] ; atrophy of the residual limb with possible hypertrophy of the sound limb 7 ; and alterations in movement strategies. 1,4,5 All of these changes are interrelated and will affect the person's ability to generate and effectively direct forces to interact with their environment.…”