The influence of a unilateral fixed ankle on metabolic and mechanical demands during walking in unimpaired young adults

Wutzke, Clinton J.; Sawicki, Gregory S.; Lewek, Michael D.

doi:10.1016/j.jbiomech.2012.06.035

Cited by 33 publications

(32 citation statements)

References 26 publications

(38 reference statements)

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“…For example, unilateral amputees compensate for asymmetric push-off with greater middle-stance work and greater positive work overall . In contrast, another study by Wutzke et al (2012) examining the effects of unilaterally fixing the ankle with a brace found greater work at the hip and greater metabolic energy expenditure, similar to our observations. But they did not find greater work at the knee, or greater mechanical work overall.…”

Section: Discussionsupporting

confidence: 88%

“…This might be the case with co-morbidities accompanying limb loss or joint fusion. For example, Wutzke et al (2012) have proposed that the hip muscles may be less efficient when replacing the work normally performed at the ankle, without having to perform more work overall. However, in the case of stroke patients, the elevated metabolic cost of walking appears to be explained by greater mechanical work (Detrembleur et al, 2003), without differences in muscle efficiency (Stoquart et al, 2005(Stoquart et al, , 2012.…”

Section: Introductionmentioning

confidence: 99%

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Mechanical and energetic consequences of reduced ankle plantarflexion in human walking

Huang

Shorter

Adamczyk

et al. 2015

Journal of Experimental Biology

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The human ankle produces a large burst of 'push-off' mechanical power late in the stance phase of walking, reduction of which leads to considerably poorer energy economy. It is, however, uncertain whether the energetic penalty results from poorer efficiency when the other leg joints substitute for the ankle's push-off work, or from a higher overall demand for work due to some fundamental feature of push-off. Here, we show that greater metabolic energy expenditure is indeed explained by a greater demand for work. This is predicted by a simple model of walking on pendulum-like legs, because proper push-off reduces collision losses from the leading leg. We tested this by experimentally restricting ankle push-off bilaterally in healthy adults (N=8) walking on a treadmill at 1.4 m s −1 , using ankle-foot orthoses with steel cables limiting motion. These produced up to ∼50% reduction in ankle pushoff power and work, resulting in up to ∼50% greater net metabolic power expenditure to walk at the same speed. For each 1 J reduction in ankle work, we observed 0.6 J more dissipative collision work by the other leg, 1.3 J more positive work from the leg joints overall, and 3.94 J more metabolic energy expended. Loss of ankle push-off required more positive work elsewhere to maintain walking speed; this additional work was performed by the knee, apparently at reasonably high efficiency. Ankle push-off may contribute to walking economy by reducing dissipative collision losses and thus overall work demand.

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Section: Discussionsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Mechanical and energetic consequences of reduced ankle plantarflexion in human walking

Huang

Shorter

Adamczyk

et al. 2015

Journal of Experimental Biology

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show abstract

“…While the small subject numbers preclude definitive statistical conclusions, this observation poses additional research hypotheses about a theoretical clinical concern that restriction of ankle movement within an AFO may be detrimental to residual paretic ankle strength and/or increase the metabolic cost of walking 15 . In this study, each AFO had a hinge that allowed limited ankle dorsiflexion range for those subjects in whom it was clinically appropriate.…”

Section: Discussionmentioning

confidence: 94%

Surface Peroneal Nerve Stimulation in Lower Limb Hemiparesis

Sheffler

Taylor

Bailey³

et al. 2015

American Journal of Physical Medicine &Amp; Rehabilitation

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Objective To evaluate possible mechanisms for functional improvement and compare ambulation training with surface peroneal nerve stimulation (PNS) versus usual care (UC) via quantitative gait analysis. Design Randomized controlled clinical trial. Setting Teaching hospital of academic medical center. Participants 110 chronic stroke survivors (> 12-wks post-stroke) with unilateral hemiparesis. Interventions Subjects were randomized to a surface PNS device or UC intervention. Subjects were treated for 12-wks and followed for 6-months post-treatment. Main Outcome Measures Spatiotemporal, kinematic, and kinetic parameters of gait. Results Cadence (F3,153=5.81, p=.012), stride length (F3,179=20.01, p<.001), walking speed (F3,167=18.2, p<.001), anterior posterior ground reaction force (F3,164=6.61, p=.004), peak hip power in pre-swing (F3,156=8.76, p<.001), and peak ankle power at push-off (F3,149=6.38, p=.005) all improved with respect to time. However, peak ankle DF in swing (F3,184=4.99, p=.031) worsened. In general, the greatest change for all parameters occurred during the treatment period. There was no significant treatment group by time interaction effects for any of the spatiotemporal, kinematic, or kinetic parameters. Conclusions Gait training with PNS and usual care was associated with improvements in peak hip power in pre-swing and peak ankle power at push-off, which may have resulted in improved cadence, stride length, and walking speed; however, there were no differences between treatment groups. Both treatment groups also experienced a decrease in peak ankle DF in swing, though the clinical implications of this finding are unclear.

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“…Trailing leg work in STS is more efficient than single support work (Kuo, 2002) and comes predominantly from the ankle while single support work comes more from the hip (Farris, Sawicki, 2012; Zelik et al, 2015). This result explains increased metabolic cost in trans-tibial amputees (Houdijk et al, 2009; Adamczyk, Kuo, 2015) and healthy subjects with immobilized ankles (Wutzke, et al, 2012). However, changes in joint work during split-belt adaptation are largely unknown.…”

Section: Introductionmentioning

confidence: 98%

Two biomechanical strategies for locomotor adaptation to split-belt treadmill walking in subjects with and without transtibial amputation

Selgrade

Toney

Chang

2017

Journal of Biomechanics

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Locomotor adaptation is commonly studied using split-belt treadmill walking, in which each foot is placed on a belt moving at a different speed. As subjects adapt to split-belt walking, they reduce metabolic power, but the biomechanical mechanism behind this improved efficiency is unknown. Analyzing mechanical work performed by the legs and joints during split-belt adaptation could reveal this mechanism. Because ankle work in the step-to-step transition is more efficient than hip work, we hypothesized that control subjects would reduce hip work on the fast belt and increase ankle work during the step-to-step transition as they adapted. We further hypothesized that subjects with unilateral, trans-tibial amputation would instead increase propulsive work from their intact leg on the slow belt. Control subjects reduced hip work and shifted more ankle work to the step-to-step transition, supporting our hypothesis. Contrary to our second hypothesis, intact leg work, ankle work and hip work in amputees were unchanged during adaptation. Furthermore, all subjects increased collisional energy loss on the fast belt, but did not increase propulsive work. This was possible because subjects moved further backward during fast leg single support in late adaptation than in early adaptation, compensating by reducing backward movement in slow leg single support. In summary, subjects used two strategies to improve mechanical efficiency in split-belt walking adaptation: a CoM displacement strategy that allows for less forward propulsion on the fast belt; and, an ankle timing strategy that allows efficient ankle work in the step-to-step transition to increase while reducing inefficient hip work.

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The influence of a unilateral fixed ankle on metabolic and mechanical demands during walking in unimpaired young adults

Cited by 33 publications

References 26 publications

Mechanical and energetic consequences of reduced ankle plantarflexion in human walking

Mechanical and energetic consequences of reduced ankle plantarflexion in human walking

Surface Peroneal Nerve Stimulation in Lower Limb Hemiparesis

Two biomechanical strategies for locomotor adaptation to split-belt treadmill walking in subjects with and without transtibial amputation

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