# The Role of Foot Structure and Function on Walking Mechanics and Energetics in Aging

> **NIH NIH F32** · UNIV OF NORTH CAROLINA CHAPEL HILL · 2020 · $67,096

## Abstract

PROJECT SUMMARY
Older adults exhibit a substantial reduction in propulsive power generation. This change in walking mechanics
is associated with slower walking speeds and greater metabolic energy expenditure – features that negatively
affect independence and quality of life. Age-related reductions in propulsive power are often attributed to
reduced ankle mechanical power during the ‘push-off’ phase of walking. Yet, strengthening the calf muscles has
been an ineffective strategy for improving push-off intensity, walking speed, and/or metabolic cost, motivating
the need for new and modifiable targets for preserving mobility in our aging population. Recent studies have
determined that the foot, independent of the ankle, plays a critical role in governing push-off intensity. The
interaction between active structures (e.g. muscles within the foot) and passive structures (e.g. plantar
aponeurosis – an elastic structure spanning the bottom of the foot) of the foot are vital to economic locomotion,
but it is unclear how this interaction facilitates forward propulsion, or how this interaction is changed with age.
We propose that age-related changes in passive and active contributions to foot stiffness may contribute to
reductions in push-off intensity in older adults, both directly via deficits in foot power and indirectly via the
misappropriation of ankle power. Aim 1: Our proposal will leverage a novel dual-probe ultrasound imaging
technique to determine the role of foot stiffness and plantar intrinsic muscle contractile dynamics in governing
foot-ankle interaction dynamics in young adults. Aim 2: We will then characterize the local energetic and
mechanical response to changes in plantar aponeurosis stiffness by closely integrating our experimental data
from Aim 1 into a computational model of the lower extremity. Aim 3: Finally, we will determine the effects of
age on foot stiffness and its role in walking economy and functional mobility. This study has the potential to
influence a paradigm shift in our biomechanical understanding and clinical management of age-related mobility
impairment. Moreover, our findings will have immediate impact on targeted mobility intervention opportunities
and innovation in the design of wearable integrated foot and ankle devices for enhanced mobility toward
improving the health and welfare of our aging population. Finally, our technological advancements in
musculoskeletal imaging will revolutionize the use of in vivo ultrasound during functional locomotor behavior,
with broad implications in humans and other animals.

## Key facts

- **NIH application ID:** 9991315
- **Project number:** 1F32AG067675-01
- **Recipient organization:** UNIV OF NORTH CAROLINA CHAPEL HILL
- **Principal Investigator:** Rebecca Lynn Krupenevich
- **Activity code:** F32 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $67,096
- **Award type:** 1
- **Project period:** 2020-05-01 → 2023-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9991315

## Citation

> US National Institutes of Health, RePORTER application 9991315, The Role of Foot Structure and Function on Walking Mechanics and Energetics in Aging (1F32AG067675-01). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9991315. Licensed CC0.

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