# Effects of anterior cruciate ligament reconstruction on the association between quadriceps muscle dynamics, knee joint biomechanics, and articular cartilage loading during walking

> **NIH NIH F31** · UNIV OF NORTH CAROLINA CHAPEL HILL · 2021 · $37,768

## Abstract

PROJECT SUMMARY
Individuals with anterior cruciate ligament reconstruction (ACLr) walk with smaller than typical peak knee
extensor moments (pKEM) and diminished knee flexion excursion during the weight acceptance phase of
walking. These deficits in voluntary quadriceps activation are considered critical in the biomechanical cascade
underlying disproportionally high rates of post-traumatic osteoarthritis (PTOA) in individuals with ACLr. It has
been suggested that changes in gait biomechanics at the knee joint can shift articular contact forces to regions
not conditioned to loading, particularly when the event allows little time for cartilage adaptation. The gait
changes observed in individuals with ACLr likely result from a combination of weakness and central inhibition
during functional activities and must be addressed with a novel rehabilitation strategy because quadriceps
strengthening alone appears unable to return gait biomechanics to uninjured values. This will be the first study
to establish mechanistic links between quadriceps kinematics, deficits in voluntary force production, and
maladaptive cartilage loading patterns in individuals with ACLr. The proposed research will use a multi-scale
approach with novel applications of gait biofeedback, in vivo ultrasound imaging, and cutting-edge knee joint
simulations. Through our pilot in vivo ultrasound testing, we observe a fundamentally different behavior in
quadriceps activation between ACLr and uninjured controls. Differences in muscle fascicle length change may
be a functional consequence of quadriceps dysfunction relevant to altered knee loading. The proposed research
builds upon this concept to evaluate quadriceps contractile dynamics during tasks requiring different functional
demands to strategically assess the effects of modulating pKEM in individuals with ACLr. Furthermore, the
proposed research will evaluate how systematic changes in quadriceps activation and knee joint biomechanics
cued via biofeedback or walking speed affect cartilage contact forces. The proposed research will have immediate
impact on our understanding of the contributions of quadriceps activation deficits in PTOA development
following ACLr.

## Key facts

- **NIH application ID:** 10234281
- **Project number:** 1F31AR078013-01A1
- **Recipient organization:** UNIV OF NORTH CAROLINA CHAPEL HILL
- **Principal Investigator:** Amanda Munsch
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $37,768
- **Award type:** 1
- **Project period:** 2021-05-01 → 2024-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10234281

## Citation

> US National Institutes of Health, RePORTER application 10234281, Effects of anterior cruciate ligament reconstruction on the association between quadriceps muscle dynamics, knee joint biomechanics, and articular cartilage loading during walking (1F31AR078013-01A1). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/10234281. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*