Improved agreement of foot segmental power and rate of energy change during gait: Inclusion of distal power terms and use of three-dimensional models

Siegel, Karen Lohmann; Kepple, Thomas M.; Caldwell, Graham E.

doi:10.1016/0021-9290(96)83336-7

Cited by 39 publications

References 13 publications

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“…2), consistent with previous studies (e.g. Siegel et al, 1996;Takahashi and Stanhope, 2013), which may undermine the energy-saving benefits of the Achilles tendon elastic recoil (Ishikawa et al, 2005;Sawicki and Ferris, 2008;Zelik et al, 2014). One possibility is that the foot absorbs substantial energy in rotation of the metatarsophalangeal joints (Bruening et al, 2012;MacWilliams et al, 2003), and that this dissipation is not beneficial to walking economy (Song and Geyer, 2011;Song et al, 2013).…”

Section: Key Scientific Implicationssupporting

confidence: 78%

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

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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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Section: Key Scientific Implicationssupporting

confidence: 78%

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

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“…Muscle joint torque is usually predicted by inverse dynamics which is a very powerful tool and widely used in gaining insight into the sum of all muscle activity at each joint (Winter, 1990). It has many potential applications in sport and clinic settings, including assessment of the effect of training and therapy, diagnosis of gait pathologies and evaluation of surgical outcomes, etc., (Winter, 1980, Winter andWhite, 1983;Siegel et al, 1996;Stefanyshyn andNigg, 1998, Lenaerts et al, 2008). Thus, joint torque is a meaningful and useful biomechanical parameter during analyzing human movement.…”

Section: Introductionmentioning

confidence: 92%

Lower extremity joint torque predicted by using artificial neural network during vertical jump

Liu

Shih

Tian

et al. 2009

Journal of Biomechanics

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“…Thus, none of these experimental methods provides a definitive answer on how work performed by muscletendon units about the ankle transfers to nonadjacent segments, or how (mechanistically) ankle push-off facilitates economical gait. Given that both the foot (distal to the ankle) and the knee are estimated to perform substantial negative work during Push-off (Siegel et al, 1996;Takahashi and Stanhope, 2013;Zelik et al, 2015a), some of the ankle push-off work may not directly accelerate the swing limb, nor the COM. Rather, a portion of ankle push-off might instead serve to offset simultaneous energy absorption or dissipation elsewhere in the body (e.g.…”

Section: Limitations Of This Perspectivementioning

confidence: 99%

A unified perspective on ankle push-off in human walking

Zelik

Adamczyk

2016

Journal of Experimental Biology

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Muscle-tendon units about the ankle joint generate a burst of positive power during the step-to-step transition in human walking, termed ankle push-off, but there is no scientific consensus on its functional role. A central question embodied in the biomechanics literature is: does ankle push-off primarily contribute to leg swing, or to center of mass (COM) acceleration? This question has been debated in various forms for decades. However, it actually presents a false dichotomy, as these two possibilities are not mutually exclusive. If we ask either question independently, the answer is the same: yes! (1) Does ankle push-off primarily contribute to leg swing acceleration? Yes. (2) Does ankle push-off primarily contribute to COM acceleration? Yes. Here, we summarize the historical debate, then synthesize the seemingly polarized perspectives and demonstrate that both descriptions are valid. The principal means by which ankle push-off affects COM mechanics is by a localized action that increases the speed and kinetic energy of the trailing push-off limb. Because the limb is included in body COM computations, this localized segmental acceleration also accelerates the COM, and most of the segmental energy change also appears as COM energy change. Interpretation of ankle mechanics should abandon an either/ or contrast of leg swing versus COM acceleration. Instead, ankle push-off should be interpreted in light of both mutually consistent effects. This unified perspective informs our fundamental understanding of the role of ankle push-off, and has important implications for the design of clinical interventions (e.g. prostheses, orthoses) intended to restore locomotor function to individuals with disabilities.

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Improved agreement of foot segmental power and rate of energy change during gait: Inclusion of distal power terms and use of three-dimensional models

Cited by 39 publications

References 13 publications

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

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

Lower extremity joint torque predicted by using artificial neural network during vertical jump

A unified perspective on ankle push-off in human walking

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