NCT06820658

A Comparison of Neuromuscular Recruitment in Trained and Untrained Adults

• Status: Recruiting
• Phase: —
• Study type: Observational
• Enrollment: 80 (estimated)
• Sponsor: Mayo Clinic · Academic / Other
• Sex: All
• Age: 60 Years – 85 Years
• Healthy volunteers: Accepted

Summary

The objective of the study is to use neurological techniques to obtain quantitative measurements of nervous system control of skeletal muscle activity in adults aged 60-85 who are either long-term resistance exercisers or who are untrained.

Detailed description

We propose to perform a cross-sectional study in 20-40 highly resistance-trained people and compare with 20-40 untrained people matched for age, sex, and BMI. in adults. Participant will complete 5 study visits. In the first visit, participants will complete a screening visit in which blood will be taken to rule out inclusion and exclusion criteria. Participants will also have their body composition measured by DEXA, Meal tolerance testing, a VO2max test on a cycle ergometer, and a muscle strength test using a knee extension machine, handgrip dynamometer and muscle motion testing. A second and third visit will be needed for meal tolerance testing will be completed and MRI of the brain. In the fourth and fifth visits, we will use transcranial magnetic stimulation (TMS) with electromyography (EMG) to track changes in in skeletal muscle excitability following cortical stimulation. In the third visit, TMS-EMG measurements will be repeated to access measurement reproducibility.

Conditions

• Healthy
• Insulin Resistance

Interventions

Type	Name	Description
DIAGNOSTIC_TEST	Neuromuscular Test	To measure neuromuscular connectivity, Transcranial Magnetic Stimulation (TMS) will be used to stimulate regions of the cerebral cortex known to control specific muscles. Electromyography (EMG) activity will then be measured from the following muscle groups: deltoid, biceps, extensor digitorum communis, abductor pollicis brevis, abductor digiti minimi, and first dorsal interosseous muscle.
DIAGNOSTIC_TEST	DEXA	The DEXA test uses X-rays to measure how many grams of calcium and other bone minerals are packed into a segment of bone. The test also measures the amount of fat-free mass, and fat mass.
DIAGNOSTIC_TEST	Mixed Meal Tolerance Test	Fasting blood will be collected for glucose, insulin, and c-peptide. Participants will be provided with a milkshake with a fixed amount of protein, carbohydrates, and fat. Glucose, insulin, and c-peptide will be measured at multiple time points (every 10 minutes) until four hours after consumption (50% Fat, 30% Carbohydrate HO, 20% Protein). Approximately 70mls of blood will be drawn during this time
DIAGNOSTIC_TEST	Strength Test	Knee extensor strength will be tested by gradually increasing the workload on a pneumatic Keiser knee extension machine. The test will begin with a warm-up of 4-5 reps with one leg at 30-50 psi. Then the participant will increase the workload at self-selected intervals ranging from 5-20psi until a maximum effort is achieved. If a rep is failed, then the workload will be reduced by 5psi until a successful rep is performed or a workload is reached in which a successful rep had been previously achieved. Handgrip strength will be tested using a handheld dynamometer (Baseline® standard hydraulic hand dynamometer). The test is performed with the participant seated with the elbow unsupported and flexed at 90 degrees, forearm neutral, wrist held between 0-15 degrees of ulnar deviation (Horowitz, 1997). Maximum grip is the average of three 3-5 second trials.

Timeline

• Start date: 2025-02-26
• Primary completion: 2028-09-01
• Completion: 2028-10-01
• First posted: 2025-02-11
• Last updated: 2025-07-30

Locations

1 site across 1 country: United States