Mechanical energy generation, absorption and transfer amongst segments during walking

Gordon, D.; Robertson, Erin; Winter, David

doi:10.1016/0021-9290(80)90172-4

Cited by 234 publications

(50 citation statements)

References 8 publications

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“…To undertake an evaluation of absolute power absorbed and returned by a dynamic response foot, a different approach is recommended [41]. Similarly, determining total mechanical work done by a physiological joint (rather than just that associated with muscle work; as was carried out in the present study), also requires a different approach [42]. …”

Section: Discussionmentioning

confidence: 99%

Walking speed related joint kinetic alterations in trans-tibial amputees: impact of hydraulic 'ankle’ damping

Asha

Munjal

Kulkarni³

et al. 2013

J NeuroEngineering Rehabil

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BackgroundPassive prosthetic devices are set up to provide optimal function at customary walking speed and thus may function less effectively at other speeds. This partly explains why joint kinetic adaptations become more apparent in lower-limb amputees when walking at speeds other than customary. The present study determined whether a trans-tibial prosthesis incorporating a dynamic-response foot that was attached to the shank via an articulating hydraulic device (hyA-F) lessened speed-related adaptations in joint kinetics compared to when the foot was attached via a rigid, non-articulating attachment (rigF).MethodsEight active unilateral trans-tibial amputees completed walking trials at their customary walking speed, and at speeds they deemed to be slow-comfortable and fast-comfortable whilst using each type of foot attachment. Moments and powers at the distal end of the prosthetic shank and at the intact joints of both limbs were compared between attachment conditions.ResultsThere was no change in the amount of intact-limb ankle work across speed or attachment conditions. As speed level increased there was an increase on both limbs in the amount of hip and knee joint work done, and increases on the prosthetic side were greater when using the hyA-F. However, because all walking speed levels were higher when using the hyA-F, the intact-limb ankle and combined joints work per meter travelled were significantly lower; particularly so at the customary speed level. This was the case despite the hyA-F dissipating more energy during stance. In addition, the amount of eccentric work done per meter travelled became increased at the residual knee when using the hyA-F, with increases again greatest at customary speed.ConclusionsFindings indicate that a trans-tibial prosthesis incorporating a dynamic-response foot reduced speed-related changes in compensatory intact-limb joint kinetics when the foot was attached via an articulating hydraulic device compared to rigid attachment. As differences between attachment conditions were greatest at customary speed, findings indicate a hydraulic ankle-foot device is most effectual at the speed it is set-up for.

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Section: Discussionmentioning

confidence: 99%

Walking speed related joint kinetic alterations in trans-tibial amputees: impact of hydraulic 'ankle’ damping

Asha

Munjal

Kulkarni³

et al. 2013

J NeuroEngineering Rehabil

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“…We computed the following mechanical estimates: (1) rate of work performed on the body center-of-mass (COM) by the individual limbs [28], (2) ankle/foot power using an inter-segmental energy balance calculation between the ankle/foot and rest of body [29], [30], [31], and (3) knee and hip joint power using standard inverse dynamics (e.g., [32]). Ankle/foot power was estimated using the inter-segmental power method rather than traditional inverse dynamics because elastic portions of prosthetic feet are difficult to model as rigid bodies [31].…”

Section: Methodsmentioning

confidence: 99%

Systematic Variation of Prosthetic Foot Spring Affects Center-of-Mass Mechanics and Metabolic Cost During Walking

Zelik

Collins

Adamczyk

et al. 2011

IEEE Trans. Neural Syst. Rehabil. Eng.

125

114

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Lower-limb amputees expend more energy to walk than non-amputees and have an elevated risk of secondary disabilities. Insufficient push-off by the prosthetic foot may be a contributing factor. We aimed to systematically study the effect of prosthetic foot mechanics on gait, to gain insight into fundamental prosthetic design principles. We varied a single parameter in isolation, the energy-storing spring in a prototype prosthetic foot, the Controlled Energy Storage and Return (CESR) foot, and observed the effect on gait. Subjects walked on the CESR foot with three different springs. We performed parallel studies on amputees and on non-amputees wearing prosthetic simulators. In both groups, spring characteristics similarly affected ankle and body center-of-mass (COM) mechanics and metabolic cost. Softer springs led to greater energy storage, energy return and prosthetic limb COM push-off work. But metabolic energy expenditure was lowest with a spring of intermediate stiffness, suggesting biomechanical disadvantages to the softest spring despite its greater push-off. Disadvantages of the softest spring may include excessive heel displacements and COM collision losses. We also observed some differences in joint kinetics between amputees and non-amputees walking on the prototype foot. During prosthetic push-off, amputees exhibited reduced energy transfer from the prosthesis to the COM along with increased hip work, perhaps due to greater energy dissipation at the knee. Nevertheless, the results indicate that spring compliance can contribute to push-off, but with biomechanical trade-offs that limit the degree to which greater push-off might improve walking economy.

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“…Human walking results from a coordinated sequence of energy generation and absorption (Gordon et al, 1980). During levelground walking at steady speed, there is an equal balance between positive and negative work production as the body undergoes no net acceleration (assuming negligible external losses).…”

Section: Introductionmentioning

confidence: 99%

“…Empirical observations indicate that during walking, substantial positive work is performed about the lower-limb joints (Elftman, 1939;Gordon et al, 1980). For convenience, we use the term 'joint work' to describe work performed by muscles, tendons and other structures at/about each joint (e.g.…”

Section: Introductionmentioning

confidence: 99%

Six degree-of-freedom analysis of hip, knee, ankle and foot provides updated understanding of biomechanical work during human walking

Zelik

Takahashi

Sawicki

2015

Journal of Experimental Biology

117

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Measuring biomechanical work performed by humans and other animals is critical for understanding muscle-tendon function, jointspecific contributions and energy-saving mechanisms during locomotion. Inverse dynamics is often employed to estimate jointlevel contributions, and deformable body estimates can be used to study work performed by the foot. We recently discovered that these commonly used experimental estimates fail to explain whole-body energy changes observed during human walking. By re-analyzing previously published data, we found that about 25% (8 J) of total positive energy changes of/about the body's center-of-mass and >30% of the energy changes during the Push-off phase of walking were not explained by conventional joint-and segment-level work estimates, exposing a gap in our fundamental understanding of work production during gait. Here, we present a novel Energy-Accounting analysis that integrates various empirical measures of work and energy to elucidate the source of unexplained biomechanical work. We discovered that by extending conventional 3 degree-of-freedom (DOF) inverse dynamics (estimating rotational work about joints) to 6DOF (rotational and translational) analysis of the hip, knee, ankle and foot, we could fully explain the missing positive work. This revealed that Push-off work performed about the hip may be >50% greater than conventionally estimated (9.3 versus 6.0 J, P=0.0002, at 1.4 m s −1). Our findings demonstrate that 6DOF analysis (of hipknee-ankle-foot) better captures energy changes of the body than more conventional 3DOF estimates. These findings refine our fundamental understanding of how work is distributed within the body, which has implications for assistive technology, biomechanical simulations and potentially clinical treatment.

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Mechanical energy generation, absorption and transfer amongst segments during walking

Cited by 234 publications

References 8 publications

Walking speed related joint kinetic alterations in trans-tibial amputees: impact of hydraulic 'ankle’ damping

Walking speed related joint kinetic alterations in trans-tibial amputees: impact of hydraulic 'ankle’ damping

Systematic Variation of Prosthetic Foot Spring Affects Center-of-Mass Mechanics and Metabolic Cost During Walking

Six degree-of-freedom analysis of hip, knee, ankle and foot provides updated understanding of biomechanical work during human walking

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