# A framework for feasible translation to enhance foot and ankle function in aging and mobility

> **NIH NIH R01** · UNIV OF NORTH CAROLINA CHAPEL HILL · 2022 · $560,728

## Abstract

PROJECT SUMMARY
This proposal will address the critical need for new and modifiable targets to enhance mobility and restore
independence to those in our rapidly aging population. Due to reduced ankle push-off power, older adults walk
slower and with higher metabolic energy cost than younger adults. As our central premise, we contend that
hallmark age-associated deficits in push-off intensity during walking have been far too often mistakenly
attributed solely to the plantarflexor muscles, and instead originate interdependently with those in the active,
passive, and structural regulation of foot mechanical power. This premise paves the way for translational
opportunities to augment foot structure and function to enhance independence and quality of life. This study
combines the research agendas of two highly productive investigators and leverages the research infrastructure
of two peer institutions. Aim 1 will be the first to study mechanical power interactions between the human foot
and ankle in governing reduced push-off intensity and walking economy in older adults across a wide variety of
everyday walking tasks. By combining metabolic measurements with state-of-the-art biomechanical and
bioenergetic modeling, we will test the hypothesis that older adults exhibit higher mechanical energy losses via
foot structures than young adults – aging effects that: (i) are larger for walking tasks that increase foot demand,
(ii) misappropriate ankle moment and power during push-off, and thereby (iii) correlate with shorter 6 min walk
distance and increased metabolic energy cost compared to young adults. Aim 2 will provide mechanistic insight
into aging effects on the active, passive, and structural regulation of foot-ankle mechanical power interactions
during walking. Using a series of controlled loading paradigms on a dynamometer combined with advanced in
vivo ultrasound imaging and novel electromyographic biofeedback, we will test the hypotheses that older adults
exhibit: (i) reduced foot and plantarflexor muscle strength and (ii) lower structural stiffness of and (iii) reduced
structural connectivity between series elastic tissues spanning the foot and ankle – changes that require elevated
plantar intrinsic muscle activation to maintain requisite foot stiffness and associate with reduced ankle moment
and power output during push-off in walking. Finally, as a translational benchmark, Aim 3 will show that shoe-
stiffness modifications that act in parallel with the plantar aponeurosis and intrinsic muscles can mitigate age-
associated deficits in push-off function during walking. Supported by promising pilot data, we will test the
hypotheses that older adults walking with increased shoe insole stiffness will exhibit: (i) smaller mechanical
energy losses at the foot, (ii) more favorable plantarflexor muscle contractile dynamics, (iii) greater peak ankle
moment and power output, and thus (iv) longer 6 min walk distance and reduced whole-body metabolic energy
c...

## Key facts

- **NIH application ID:** 10501648
- **Project number:** 1R01AR081287-01
- **Recipient organization:** UNIV OF NORTH CAROLINA CHAPEL HILL
- **Principal Investigator:** Jason R Franz
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $560,728
- **Award type:** 1
- **Project period:** 2022-09-15 → 2027-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10501648

## Citation

> US National Institutes of Health, RePORTER application 10501648, A framework for feasible translation to enhance foot and ankle function in aging and mobility (1R01AR081287-01). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10501648. Licensed CC0.

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