Associations Between Foot Placement Asymmetries and Metabolic Cost of Transport in Hemiparetic Gait

Finley, James M.; Bastian, Amy J.

doi:10.1177/1545968316675428

Cited by 44 publications

(89 citation statements)

References 48 publications

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“…Two of these studies, in particular, suggested that increased gait asymmetry in people post-stroke is correlated with the increased metabolic cost of walking Farris et al, 2015). There is thus great interest in the development of post-stroke gait interventions that can reduce the metabolic cost of walking by inducing more symmetrical walking (Finley and Bastian, 2017).…”

Section: Introductionmentioning

confidence: 99%

Biomechanical mechanisms underlying exosuit-induced improvements in walking economy after stroke

Bae

Awad

Long

et al. 2018

Journal of Experimental Biology

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Stroke-induced hemiparetic gait is characteristically asymmetric and metabolically expensive. Weakness and impaired control of the paretic ankle contribute to reduced forward propulsion and ground clearance - walking subtasks critical for safe and efficient locomotion. Targeted gait interventions that improve paretic ankle function after stroke are therefore warranted. We have developed textile-based, soft wearable robots that transmit mechanical power generated by off-board or body-worn actuators to the paretic ankle using Bowden cables (soft exosuits) and have demonstrated the exosuits can overcome deficits in paretic limb forward propulsion and ground clearance, ultimately reducing the metabolic cost of hemiparetic walking. This study elucidates the biomechanical mechanisms underlying exosuit-induced reductions in metabolic power. We evaluated the relationships between exosuit-induced changes in the body center of mass (COM) power generated by each limb, individual joint power and metabolic power. Compared with walking with an exosuit unpowered, exosuit assistance produced more symmetrical COM power generation during the critical period of the step-to-step transition (22.4±6.4% more symmetric). Changes in individual limb COM power were related to changes in paretic (=0.83, 0.004) and non-paretic (0.73, 0.014) ankle power. Interestingly, despite the exosuit providing direct assistance to only the paretic limb, changes in metabolic power were related to changes in non-paretic limb COM power (=0.80, 0.007), not paretic limb COM power (0.05). These findings contribute to a fundamental understanding of how individuals post-stroke interact with an exosuit to reduce the metabolic cost of hemiparetic walking.

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Section: Introductionmentioning

confidence: 99%

Biomechanical mechanisms underlying exosuit-induced improvements in walking economy after stroke

Bae

Awad

Long

et al. 2018

Journal of Experimental Biology

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“…To evaluate the physical realism of each musculoskeletal modeling approach/metabolic cost model combination, we identified five experimental trends in the literature for how CoT varies with other quantities for individuals post-stroke. The first three quantities were step position asymmetry, stance time asymmetry, and double-support time asymmetry that were reported to increase as the cost of transport increased (Finley and Bastian, 2017). Inversely, the two other quantities were speed and Fugl-Meyer score that were observed to decrease as the cost of transport increased.…”

Section: Discussionmentioning

confidence: 97%

“…To evaluate the physical realism of different metabolic cost modeling methods, we compared metabolic cost estimates to trends reported in the literature. For individuals post-stroke, Finley and Bastian (Finley and Bastian, 2017) reported a decrease in metabolic cost as walking speed increased and severity of motor impairment decreased. In contrast, for the same subject population, Finley and colleagues (Finley et al, 2015;Finley and Bastian, 2017) also reported that metabolic cost increased as differences in step position, stance time, and double support time increased.…”

Section: Model Personalization Affects Metabolic Cost?mentioning

confidence: 99%

“…For individuals post-stroke, Finley and Bastian (Finley and Bastian, 2017) reported a decrease in metabolic cost as walking speed increased and severity of motor impairment decreased. In contrast, for the same subject population, Finley and colleagues (Finley et al, 2015;Finley and Bastian, 2017) also reported that metabolic cost increased as differences in step position, stance time, and double support time increased. The present study evaluated a previously acquired gait data set from which metabolic cost measurements were not available.…”

Section: Model Personalization Affects Metabolic Cost?mentioning

confidence: 99%

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Musculoskeletal Model Personalization Affects Metabolic Cost Estimates for Walking

Arones

Shourijeh

Patten

et al. 2020

Preprint

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Assessment of metabolic energy cost as a metric for human performance has expanded across various fields within the scientific, clinical, and engineering communities. As an alternative to measuring metabolic cost experimentally, musculoskeletal models incorporating metabolic cost models have been developed. However, to utilize these models for practical applications, the accuracy of their metabolic cost predictions requires improvement. Previous studies have reported the benefits of using personalized musculoskeletal models for various applications, yet no study has evaluated how model personalization affects metabolic cost estimation. This study investigated the effect of musculoskeletal model personalization on estimates of metabolic cost of transport (CoT) during post-stroke walking using three commonly used metabolic cost models. We analyzed data previously collected from two male stroke survivors with right-sided hemiparesis. The three metabolic cost models were implemented within three musculoskeletal modeling approaches involving different levels of personalization. The first approach used a scaled generic OpenSim model and found muscle activations via static optimization (SOGen). The second approach used a personalized EMG-driven musculoskeletal model with personalized functional axes but found muscle activations via static optimization (SOCal). The third approach used the same personalized EMG-driven model but calculated muscle activations directly from EMG data (EMGCal). For each approach, the muscle activation estimates were used to calculate each subject’s cost of transport (CoT) at different gait speeds using three metabolic cost models (Umberger 2003, Umberger 2010, and Bhargava 2004). The calculated CoT values were compared with published CoT trends as a function of stance time, double support time, step positions, walking speed, and severity of motor impairment (i.e., Fugl-Meyer score). Overall, U10-SOCal, U10-EMGCal, U03-SOCal, and U03-EMGCal were able to produce slopes between CoT and the different measures of walking asymmetry that were statistically similar to those found in the literature. Although model personalization seemed to improve CoT estimates, further tuning of parameters associated with the different metabolic cost models in future studies may allow for realistic CoT predictions. An improvement in CoT predictions may allow researchers to predict human performance, surgical, and rehabilitation outcomes reliably using computational simulations.

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“…Poststroke changes in lower extremity function lead to persistent biomechanical abnormalities during walking including but not limited to decreased paretic stance time 3 , and asymmetric step lengths [4][5][6][7] . Previous research has shown positive associations between spatiotemporal asymmetries and the metabolic cost of walking [8][9][10] , and in people post-stroke, this increased cost may be due in part to sub-optimal coordination of leading limb contact and trailing limb push-off forces 10,11 . Therefore, it is possible that reducing asymmetry may reduce the metabolic burden of walking post-stroke.…”

Section: Introductionmentioning

confidence: 98%

Individual differences in locomotor function predict the capacity to reduce asymmetry and modify the energetic cost of walking post-stroke

Sánchez

Finley

2017

Preprint

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Changes in the control of the lower extremities post-stroke lead to persistent biomechanical asymmetries during walking. These asymmetries are associated with an increase in energetic cost, leading to the possibility that reduction of asymmetry can improve economy. However, the influence of asymmetry on economy may depend on the direction and cause of asymmetry. For example, impairments with paretic limb advancement may result in shorter paretic steps while deficits in paretic support or propulsion result in shorter non-paretic steps. Given differences in the underlying impairments responsible for each type of step length asymmetry, the capacity to reduce asymmetry, and the associated changes in energetic cost may not be consistent across this population. Here, we identified factors explaining individual differences in the capacity to voluntarily reduce step length asymmetry and modify energetic cost during walking. Twenty-four individuals post-stroke walked on a treadmill with visual feedback of their step lengths to aid explicit modification of asymmetry. We found that individuals who naturally took longer paretic steps had a greater capacity to reduce asymmetry, and were better able to transfer the effects of training to over-ground walking. In addition, baseline energetic cost was negatively correlated with reductions in cost, such that participants with a more economical gait were more likely to reduce energetic cost by improving symmetry. These results demonstrate that many stroke survivors retain the capacity to voluntarily walk more symmetrically on a treadmill and overground. However, whether reductions in asymmetry reduce metabolic cost depends on individual differences in impairments affecting locomotor function.

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Associations Between Foot Placement Asymmetries and Metabolic Cost of Transport in Hemiparetic Gait

Cited by 44 publications

References 48 publications

Biomechanical mechanisms underlying exosuit-induced improvements in walking economy after stroke

Biomechanical mechanisms underlying exosuit-induced improvements in walking economy after stroke

Musculoskeletal Model Personalization Affects Metabolic Cost Estimates for Walking

Individual differences in locomotor function predict the capacity to reduce asymmetry and modify the energetic cost of walking post-stroke

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