University of Central Florida
Orlando, Florida, 32816, United States
Location status: Recruiting
Recruiting
NCT Number: NCT06999057
Quadriceps Motor Unit Adaptation to Simulated Knee Injury
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.
Recruiting
Interested in participating?
Request InfoKey information
Conditions
Age range
18 year–30 year
Sex eligibility
All sexes
Study type
Interventional
Phase
Early Phase 1
Primary location
About this study
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.
Who can participate
Healthy volunteers accepted: Yes
Only the study team can determine whether someone qualifies for participation.
Inclusion criteria
- Age 18-30 years
- Physically active (Tegner ≥ 5)
- No prior lower-limb surgery or major injury
Exclusion criteria
- Lower limb surgery or significant injury in past 2 years
- Cardiopulmonary, neurological, or psychiatric disorders
- Needle/electrical stimulation anxiety
- Medications affecting neuromuscular or psychological function
- Pregnancy
- Allergic to lidocaine
- Inability to elicit Hoffmann reflex
Treatment and study plan
Joint Effusion via 60 mL Sterile Saline
DeviceInjection of sterile saline into the knee joint to simulate joint swelling and induce quadriceps inhibition.
Intra-articular Lidocaine
DrugInjection of 7 mL lidocaine into the knee joint to simulate deafferentation by temporarily blocking sensory input.
Sham Injection
OtherSimulated knee injection using a stage needle without skin penetration, used to blind participants and serve as control.
Primary outcomes
-
Motor Unit Recruitment (amplitude relative to recruitment threshold)
Time frame: Baseline, 0, 30, and 60 minutes post-intervention
Measured via surface EMG decomposition
-
Motor Unit Recruitment (firing rate relative to recruitment threshold)
Time frame: Baseline, 0, 30, and 60 minutes post-intervention
Measured via surface EMG decomposition
Secondary outcomes
-
Quadriceps Inhibition (Hoffmann Reflex)
Time frame: Baseline, 0 and 60 minutes post-intervention
Measured with femoral nerve stimulation
-
Isometric Peak Torque (Quadriceps Strength)
Time frame: Baseline and 60 minutes post-intervention
Measured with isokinetic dynamometer (Biodex)
Study contacts
Contact information is provided by the study sponsor or research team.
Grant Norte, Ph.D.
CONTACT
Meredith Chaput, Ph.D.
CONTACT
Sponsors and collaborators
Lead sponsor
University of Central Florida
Other
Registry information
Important dates
- Study start
- 2026
- Primary completion
- 2027
- Study completion
- 2027
- First posted
- May 31, 2025
- Registry last updated
- May 1, 2026
OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.
View the official ClinicalTrials.gov record (opens in a new tab)This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.