# Noninvasive tools for assessing muscle structure and function

> **NIH NIH R01** · NORTHWESTERN UNIVERSITY · 2023 · $678,491

## Abstract

Project Summary
Changes in muscle force and stiffness underlie the control of posture and movement. These fundamental abilities
are impaired in almost all movement disorders, including those resulting from stroke, cerebral palsy,
musculoskeletal injury, or pain. Rehabilitation can be framed in terms of re-establishing healthy patterns of
muscle force and stiffness for each patient. Consequently, a fundamental challenge in the fields of biomechanics,
motor control, and physical rehabilitation has long been measuring muscle force and stiffness in health and
disease, yet there are no rigorous methods for doing so noninvasively. Ultrasound shear wave elastography
(SWE) was proposed as a noninvasive tool for measuring stiffness, but we have demonstrated that SWE is
sensitive not only to muscle stiffness but also to force, and that these dependencies vary across muscle types.
While our results call into question conclusions from many previous studies, they also suggest that SWE could
be reimagined as a tool for noninvasively measuring both stiffness and force. The objective of this proposal is to
evaluate this intriguing possibility, which could transform the study of human movement and guide rehabilitation
protocols for numerous motor disorders.
 Our long-term goal is to improve treatments for musculoskeletal disorders associated with changes to muscle
force or stiffness. Our central hypothesis is that muscle stiffness and force can be uniquely determined from
SWE by considering the distinctive structure of muscle. Shear wave propagation is sensitive to changes in
muscle stress (force normalized by cross-sectional area) and stiffness, but it remains unknown if SWE can
independently measure these quantities. Aims 1 and 2 will quantify how stresses from passive lengthening and
active contraction alter shear wave propagation parallel to the direction of muscle fibers, as measured by the
one-dimensional ultrasound arrays currently available in clinics. Studies will be conducted in an animal model
so that SWE measurements can be compared to direct measures of muscle stiffness and stress (Aim 1), before
considering the complexities of several human muscles thought to have internal variations in stress (Aim 2).
Finally, we will evaluate the novel technique we have developed that uses multi-directional SWE to determine
muscle stress and stiffness noninvasively (Aim 3); this will occur using a combination of 3D-printed biomaterials
with known mechanical properties, muscles harvested from our animal model, and human experiments to
rigorously test this innovative approach and adapt it as needed to account for the unique structure of muscle.
 We expect that our aims will clarify precisely what is being measured by current applications of SWE to
muscle and determine if a novel approach employing multidirectional SWE can be used to measure muscle force
and stiffness noninvasively. Such an ability would be transformative for rehabilitation, providing quantitative
as...

## Key facts

- **NIH application ID:** 10696947
- **Project number:** 5R01AR071162-07
- **Recipient organization:** NORTHWESTERN UNIVERSITY
- **Principal Investigator:** ERIC JON PERREAULT
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2023
- **Award amount:** $678,491
- **Award type:** 5
- **Project period:** 2022-09-03 → 2027-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10696947

## Citation

> US National Institutes of Health, RePORTER application 10696947, Noninvasive tools for assessing muscle structure and function (5R01AR071162-07). Retrieved via AI Analytics 2026-05-21 from https://api.ai-analytics.org/grant/nih/10696947. Licensed CC0.

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