# Quantification of dynamic ankle mechanics for assessment and treatment of locomotor dysfunction post stroke

> **NIH NIH R21** · UNIVERSITY OF MICHIGAN AT ANN ARBOR · 2020 · $219,568

## Abstract

PROJECT SUMMARY
Stroke is the leading cause of adult-onset disability; however, treatment of the locomotor dysfunction that usually
results has been limited. Individuals who experience a stroke often continuously and inadvertently contract their
muscles due to changes in how the brain coordinates movement, among other mechanisms. This extra muscle
contraction causes unwanted resistance—known as increased joint stiffness and viscosity. Patients must fight
against this resistance during locomotion, and consequently, locomotor function is severely impaired. To treat
the resulting gait deficits, clinicians use coarse, qualitative assessments performed while the patient is relaxed
and their leg is not bearing weight. Although treatments based on these assessments have had some success
in reducing altered limb mechanics in resting conditions, these improvements have not extended to functional
benefits in locomotion. Thus, current clinical practice is hindered by the coarse, qualitative nature of the
assessment metrics, as well as the mismatch between passive assessment and the desired improvements in
dynamic activities, such as walking.
Despite much knowledge of joint stiffness during resting conditions, scientific and engineering challenges have
prevented the study of these properties during gait, where they could be used to inform clinical treatment. Over
the past several years, our group has overcome these challenges, pioneering a new approach to measure the
stiffness and viscosity of the ankle dynamically during locomotion. We previously quantified how these properties
vary during walking in able-bodied individuals, which led to the development of a new class of ankle prostheses.
Although we have begun to study how ankle stiffness and viscosity change throughout walking in healthy
individuals, there is a gap in our knowledge of how pathology alters these properties during locomotion, and how
this knowledge can impact clinical treatment. Joint stiffness and viscosity are especially important in assessment
of individuals post-stoke because these properties directly characterize the unwanted resistance that occurs.
The specific objective of this proposal is to leverage our innovative approach to investigate how ankle joint
stiffness and viscosity vary during walking in individuals post-stroke, and compare these data to existing
assessments and age-matched control subjects. Our rationale is that knowledge of how these properties change
throughout walking will provide new, fundamental information that can be used to understand, assess, and treat
the functional aspects of altered joint mechanics. Our hypothesis is that joint stiffness and viscosity will be greater
in individuals post-stroke, when compared to healthy, age-matched control subjects. This work will provide a
new understanding of impaired walking mechanics, and provide a novel, quantitative method to dynamically
assess and track the changes that occur following neural injury. Finally, the inf...

## Key facts

- **NIH application ID:** 9857050
- **Project number:** 5R21HD097663-02
- **Recipient organization:** UNIVERSITY OF MICHIGAN AT ANN ARBOR
- **Principal Investigator:** Elliott J Rouse
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $219,568
- **Award type:** 5
- **Project period:** 2019-02-01 → 2022-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9857050

## Citation

> US National Institutes of Health, RePORTER application 9857050, Quantification of dynamic ankle mechanics for assessment and treatment of locomotor dysfunction post stroke (5R21HD097663-02). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9857050. Licensed CC0.

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