Task dependent changes in mechanical and biomechanical measures result from manipulating stiffness settings in a prosthetic foot

Ármannsdóttir, Anna Lára; Lecomte, Christophe; Brynjólfsson, Sigurður; Briem, Kristín

doi:10.1016/j.clinbiomech.2021.105476

Cited by 4 publications

(3 citation statements)

References 39 publications

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“…This regression analysis supports the conclusions of prior investigations on the effect of prosthesis stiffness on biomechanics. As in prior work, we demonstrated that ankle stiffness is linearly and inversely correlated with peak dorsiflexion angle 23 , 38 and energy storage and return 23 . Although forefoot stiffness differs from ankle joint stiffness, this work provides a similar result to experiments that analyze the effects of forefoot stiffness changes on dorsiflexion angle, energy return, and prosthetic power 42 , 44 .…”

Section: Discussionsupporting

confidence: 85%

“…The development of these quasi-passive devices has enabled valuable insight into the role of changing stiffness on the biomechanics of walking. Variable-stiffness prosthetic ankle devices have demonstrated increased dorsiflexion range of motion with a decrease in ankle stiffness 23 , 38 and increased energy storage for lower stiffnesses 23 . Experiments on preferred stiffness and perception of prosthetic ankle stiffness change by users 39 , 40 , as well as the stiffness preferences of prescribing prosthetists 41 has shown a preference for lower stiffnesses at slower walking speeds by users 40 , and higher stiffnesses preferred by prosthetists than by the users at preferred walking speeds 41 .…”

Section: Introductionmentioning

confidence: 99%

“…There has yet to be a microprocessor-controlled variable-stiffness ankle-foot prosthesis that demonstrates an improvement in full body biomechanics across a range of walking speeds. While providing important biomechanical insights, the majority of prior studies analyze biomechanics at a single walking speed 22 , 38 , 39 , 42 , do not evaluate whole-body mechanics 40 , or evaluate effects of forefoot stiffness only 44 . Furthermore, prior studies do not provide comparison with standard passive devices, preventing conclusions regarding practical benefits of such variable-stiffness devices or their relative potential impacts across walking speeds compared to lower-mass passive devices operating at fixed stiffnesses.…”

Section: Introductionmentioning

confidence: 99%

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Variable-stiffness prosthesis improves biomechanics of walking across speeds compared to a passive device

Rogers-Bradley,

Yeon,

Landis

et al. 2024

Sci Rep

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Ankle push-off power plays an important role in healthy walking, contributing to center-of-mass acceleration, swing leg dynamics, and accounting for 45% of total leg power. The majority of existing passive energy storage and return prostheses for people with below-knee (transtibial) amputation are stiffer than the biological ankle, particularly at slower walking speeds. Additionally, passive devices provide insufficient levels of energy return and push-off power, negatively impacting biomechanics of gait. Here, we present a clinical study evaluating the kinematics and kinetics of walking with a microprocessor-controlled, variable-stiffness ankle-foot prosthesis (945 g) compared to a standard low-mass passive prosthesis (Ottobock Taleo, 463 g) with 7 study participants having unilateral transtibial amputation. By modulating prosthesis stiffness under computer control across walking speeds, we demonstrate that there exists a stiffness that increases prosthetic-side energy return, peak power, and center-of-mass push-off work, and decreases contralateral limb peak ground reaction force compared to the standard passive prosthesis across all evaluated walking speeds. We demonstrate a significant increase in center-of-mass push-off work of 26.1%, 26.2%, 29.6% and 29.9% at 0.75 m/s, 1.0 m/s, 1.25 m/s, and 1.5 m/s, respectively, and a significant decrease in contralateral limb ground reaction force of 3.1%, 3.9%, and 3.2% at 1.0 m/s, 1.25 m/s, and 1.5 m/s, respectively. This study demonstrates the potential for a quasi-passive microprocessor-controlled variable-stiffness prosthesis to increase push-off power and energy return during gait at a range of walking speeds compared to a passive device of a fixed stiffness.

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