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Author Notes:

Correspondence: Brian A Knarr, Email: bknarr@udel.edu

Authors' Contributions: BK created the musculoskeletal models, analyzed the data, and drafted the manuscript.

TK participated in the design of the study and coordination and helped to draft the manuscript.

DR conceived of the study, and participated in its design and coordination and helped to draft the manuscript.

SBM conceived of the study, and participated in its design and coordination and helped to draft the manuscript.

JS conceived of the study, and participated in its design and coordination and helped to draft the manuscript.

All authors read and approved the final manuscript.

Acknowledgment: We would like to acknowledge Erin Helm and Dylan Fitzgerald for their assistance with data collection.

Disclosures: The authors declare that they have no competing interests.

Subject:

Research Funding:

Funding was provided by NIH NS 055383 and NIH NR 010786.

Changes in the activation and function of the ankle plantar flexor muscles due to gait retraining in chronic stroke survivors

Tools:

Journal Title:

Journal of NeuroEngineering and Rehabilitation

Volume:

Volume 10, Number 12

Publisher:

, Pages 1-8

Type of Work:

Article | Final Publisher PDF

Abstract:

Background A common goal of persons post-stroke is to regain community ambulation. The plantar flexor muscles play an important role in propulsion generation and swing initiation as previous musculoskeletal simulations have shown. The purpose of this study was to demonstrate that simulation results quantifying changes in plantar flexor activation and function in individuals post-stroke were consistent with (1) the purpose of an intervention designed to enhance plantar flexor function and (2) expected muscle function during gait based on previous literature. Methods Three-dimensional, forward dynamic simulations were created to determine the changes in model activation and function of the paretic ankle plantar flexor muscles for eight patients post-stroke after a 12-weeks FastFES gait retraining program. Results An median increase of 0.07 (Range [−0.01,0.22]) was seen in simulated activation averaged across all plantar flexors during the double support phase of gait from pre- to post-intervention. A concurrent increase in walking speed and plantar flexor induced forward center of mass acceleration by the plantar flexors was seen post-intervention for seven of the eight subject simulations. Additionally, post-training, the plantar flexors had an simulated increase in contribution to knee flexion acceleration during double support. Conclusions For the first time, muscle-actuated musculoskeletal models were used to simulate the effect of a gait retraining intervention on post-stroke muscle model predicted activation and function. The simulations showed a new pattern of simulated activation for the plantar flexor muscles after training, suggesting that the subjects activated these muscles with more appropriate timing following the intervention. Functionally, simulations calculated that the plantar flexors provided greater contribution to knee flexion acceleration after training, which is important for increasing swing phase knee flexion and foot clearance.

Copyright information:

© 2013 Knarr et al.; licensee BioMed Central Ltd.

This is an Open Access work distributed under the terms of the Creative Commons Attribution 2.0 Generic License (http://creativecommons.org/licenses/by/2.0/).

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