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NCT06999057EARLY_PHASE1RecruitingAccepts Healthy Volunteers

Quadriceps Motor Unit Adaptation to Simulated Knee Injury

University of Central Florida

Start Date

8/1/2026

Completion Date

8/1/2027

Summary

This study investigates how simulated knee injury-via artificial joint effusion or deafferentation-affects quadriceps motor unit behavior in healthy young adults. Participants will complete neuromuscular testing during a single 2-hour lab session. This research seeks to improve understanding of muscle inhibition and inform interventions after real-world knee trauma.

Detailed Description

Using a controlled laboratory model, the investigators will simulate knee injury through two methods: (1) intra-articular saline injection to induce effusion, and (2) intra-articular lidocaine injection to induce sensory deafferentation. Healthy participants aged 18-30 will undergo surface and decomposition EMG, isometric strength testing, and reflex measurements before and after the intervention. The primary outcome is motor unit recruitment characteristics, with secondary outcomes including quadriceps inhibition (Hoffmann reflex) and isometric peak torque. The findings will inform future neuromodulatory approaches in rehabilitation.

Eligibility Criteria

Age Range: 18 years to 30 years

Inclusion Criteria: 1. Age 18-30 years 2. Physically active (Tegner ≥ 5) 3. No prior lower-limb surgery or major injury Exclusion Criteria: 1. Lower limb surgery or significant injury in past 2 years 2. Cardiopulmonary, neurological, or psychiatric disorders 3. Needle/electrical stimulation anxiety 4. Medications affecting neuromuscular or psychological function 5. Pregnancy 6. Allergic to lidocaine 7. Inability to elicit Hoffmann reflex

Interventions

DEVICE

Joint Effusion via 60 mL Sterile Saline

DRUG

Intra-articular Lidocaine

OTHER

Sham injection

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Conditions

Muscle InhibitionKnee Injury Simulation

Locations

University of Central Florida

Orlando, Florida 32816

United States