A modeling study of mechanical energetic optimality in incline walking

Oh, Keonyoung; Ryu, Jae-Kwan; Park, Sukyung

doi:10.1007/s12206-014-0126-2

Cited by 3 publications

(4 citation statements)

References 39 publications

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“…These results are in accordance with those of Gottschall and Kram [ 45 ]. According to Oh et al [ 46 ], from a purely mechanical perspective, the external work would be minimal if the positive work done during the double support phase was equal to the potential energy necessary to overcome the slope and was followed by a single support phase during which the COM vaults passively over a stiff limb. However, generating a large magnitude of work over a short time duration may be metabolically expensive for muscles [ 45 ] and most likely exceed a maximum suitable push-off limit [ 46 ].…”

Section: Discussionmentioning

confidence: 99%

“…According to Oh et al [ 46 ], from a purely mechanical perspective, the external work would be minimal if the positive work done during the double support phase was equal to the potential energy necessary to overcome the slope and was followed by a single support phase during which the COM vaults passively over a stiff limb. However, generating a large magnitude of work over a short time duration may be metabolically expensive for muscles [ 45 ] and most likely exceed a maximum suitable push-off limit [ 46 ]. Instead, to prevent pitching backward when moving on an incline, the hip and knee flexion increases at foot contact [ 47 , 48 ] and mechanical work is performed to raise the COM of the body during T1 when extending the knee and hip [ 21 ].…”

Section: Discussionmentioning

confidence: 99%

“…Walking downhill on steeper slopes and at higher speeds involves greater negative external work during double support ( Fig 10 ) and this work is mainly done by the leading leg but also by the trailing leg [ 43 , 44 ]. Similar to uphill walking, the external work performed during downhill walking is predicted to be minimal if the negative work done during the double contact was equal to the decrease in potential energy due to the slope and if no additional work was done during the single support phase [ 46 ]. Our results show that, at low walking speed, R avg is small during T3 suggesting that negative muscle-tendon work is performed to control the velocity of the COM during the descent ( Fig 10 ) and to restrain the body from falling [ 50 ].…”

Section: Discussionmentioning

confidence: 99%

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Pendular energy transduction within the step during human walking on slopes at different speeds

et al. 2017

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When ascending (descending) a slope, positive (negative) work must be performed to overcome changes in gravitational potential energy at the center of body mass (COM). This modifies the pendulum-like behavior of walking. The aim of this study is to analyze how energy exchange and mechanical work done vary within a step across slopes and speeds. Ten subjects walked on an instrumented treadmill at different slopes (from -9° to 9°), and speeds (between 0.56 and 2.22 m s-1). From the ground reaction forces, we evaluated energy of the COM, recovery (i.e. the potential-kinetic energy transduction) and pendular energy savings (i.e. the theoretical reduction in work due to this recovered energy) throughout the step. When walking uphill as compared to level, pendular energy savings increase during the first part of stance (when the COM is lifted) and decreases during the second part. Conversely in downhill walking, pendular energy savings decrease during the first part of stance and increase during the second part (when the COM is lowered). In uphill and downhill walking, the main phase of external work occurs around double support. Uphill, the positive work phase is extended during the beginning of single support to raise the body. Downhill, the negative work phase starts before double support, slowing the downward velocity of the body. Changes of the pendulum-like behavior as a function of slope can be illustrated by tilting the 'classical compass model' backwards (uphill) or forwards (downhill).

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Pendular energy transduction within the step during human walking on slopes at different speeds

et al. 2017

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“…Furthermore, the joint torque profile can be further improved by modeling the joint to rotate freely, because the difference of the CoP excursion between the curvy foot and the human foot [12] can be reduced by regulating the rotation of the curvy foot. A previous research also reflected the human leg configuration in incline walking and predicted the optimal propulsion to minimize the total work done [13].…”

Section: Discussionmentioning

confidence: 99%

Compliant walking model with a curvy foot reflecting the position of ankle on reproducing the ankle torque profile

Lim

Park

2015

J Mech Sci Technol

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Compliant walking model served as a theoretical framework because of the generation of kinetic information of human walking. Moreover, as Whittington applied a curvy foot to the compliant walking model, the exaggerated ratio of the vertical ground reaction force (GRF) to the horizontal GRF and the fixed center of pressure during the single stance phase have been solved. However, giving meaning to the stiffness of the compliant leg became difficult because of the exaggerated height of the foot and the shortened leg length. Moreover, joint torque was not compared with the ankle torque because the joint position is different from the ankle position. Thus, in this study, we modified the compliant walking model with a curvy foot that reflects the configuration of the human leg and examined whether the modified compliant walking model with a curvy foot could represent human walking. We reflected the configuration of the human leg to the model by shortening the height of the curvy foot, lengthening the compliant leg length, and shifting the joint position similar to the ankle position. To confirm the feasibility of the modified model and to examine the effect of shifting the joint position, we compared the simulation data with the experimental data: the GRF obtained with the force plate and the ankle torque obtained with the inverse dynamics through kinematic data. Thus, the modified model can reproduce the symmetric M-shape of the GRF but not the asymmetric shape of the model. Furthermore, the modified model can also produce the joint torque profile similar to the ankle torque profile. In conclusion, considering the human leg configuration can provide us with information about human walking.

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Change in telescoping leg strategy with varying walking speed to modulate force advantage

Kim

Park

2020

Journal of Theoretical Biology

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A modeling study of mechanical energetic optimality in incline walking

Cited by 3 publications

References 39 publications

Pendular energy transduction within the step during human walking on slopes at different speeds

Pendular energy transduction within the step during human walking on slopes at different speeds

Compliant walking model with a curvy foot reflecting the position of ankle on reproducing the ankle torque profile

Change in telescoping leg strategy with varying walking speed to modulate force advantage

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