Long jumpers with and without a transtibial amputation have different three-dimensional centre of mass and joint take-off step kinematics

Abstract

Long jumpers with below the knee amputation (BKA) have achieved remarkable performances, yet the underlying biomechanics resulting in these jump distances are unknown. We measured three-dimensional motion and used multi-segment modelling to quantify and compare the centre of mass (COM) and joint kinematics of three long jumpers with BKA and seven non-amputee long jumpers during the take-off step of the long jump. Despite having the same jump distances, athletes with BKA, who used their affected leg for the take-off step, had lower sagittal plane hip and knee joint range of motion and positioned their affected leg more laterally relative to the COM compared to non-amputee athletes. Athletes with BKA had a longer compression phase and greater downward movement of their COM, suggesting that their affected leg (lever) was less rigid compared to the biological leg of non-amputees. Thus, athletes with BKA used a different kinematic mechanism to redirect horizontal to vertical velocity compared to non-amputee athletes. The specific movement patterns of athletes with BKA during the take-off step were constrained by the mechanical properties of the prosthesis. These results provide a basis for coaches and athletes to develop training protocols that improve performance and inform the design of future prostheses.

How Can Biomechanics Improve Physical Preparation and Performance in Paralympic Athletes? A Narrative Review

“…However, energy is stored (a portion of which is returned) in running-specific prostheses that may exceed that of a biological limb. In support, Funken et al [ 32 ] have shown that unilateral lower-limb amputees have a longer compression phase and a greater downward motion of the centre of mass, which would be effective in generating vertical impulse and storing and returning energy within the running-specific prostheses. An optimal running-specific prosthetic stiffness, one that maximizes the storage and return of energy while also maximizing the pivot that translates a portion of the horizontal velocity to vertical velocity at take-off [ 31 ] should be investigated.…”

Asymmetry in Three-Dimensional Sprinting with and without Running-Specific Prostheses

“…On the one hand, the reduced torque in the knee joint of the affected leg could indicate that this joint is likewise affected by the amputation. On the other hand, there are indicators that the conscious stiffening of the knee joint could be a strategy to make optimal use of the prosthesis [26,27]. At first glance, it seems appropriate in this context that the passive torque generated in the prosthetic ankle is almost twice as high as in the biological ankle.…”

The Natural-Artificial Distinction and the Technologization of Sport

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