NCT06999057

Quadriceps Motor Unit Adaptation to Simulated Knee Injury

• Status: Not Yet Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 45 (estimated)
• Sponsor: University of Central Florida · Academic / Other
• Sex: All
• Age: 18 Years – 30 Years
• Healthy volunteers: Accepted

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.

Conditions

• Muscle Inhibition
• Knee Injury Simulation

Interventions

Type	Name	Description
DEVICE	Joint Effusion via 60 mL Sterile Saline	Injection of sterile saline into the knee joint to simulate joint swelling and induce quadriceps inhibition.
DRUG	Intra-articular Lidocaine	Injection of 7 mL lidocaine into the knee joint to simulate deafferentation by temporarily blocking sensory input.
OTHER	Sham injection	Simulated knee injection using a stage needle without skin penetration, used to blind participants and serve as control.

Timeline

• Start date: 2025-08-01
• Primary completion: 2026-06-01
• Completion: 2026-06-01
• First posted: 2025-05-31
• Last updated: 2025-05-31