EC Wisconsin News

Lakeland University Assistant Professor of Exercise Science Caleb Voskuil, Ph.D., has contributed to research that will be published by the American Physiological Society in the Journal of Neurophysiology this fall. Voskuil worked with colleagues from Texas Christian University, Kansas State University, and the University of Central Florida to study how individual nerve-muscle "motor units" behave during near-maximal biceps curls in a group of 35 healthy adults.

The team used a high-density wearable EMG sensor along with AI-based signal analysis to track 1,361 motor units. Their findings showed that even a small increase in load caused the motor-unit system to fire more strongly, but did not change the overall recruitment pattern.

Researchers also found clear differences between men and women at high intensities. Men had higher firing rates and larger motor-unit signals than women, which aligns with a greater contribution from larger, fast-twitch muscle fibers.

“The findings show that motor-unit behavior adapts to load during real-world movements and point to meaningful sex-specific considerations for strength training and rehabilitation,” said Voskuil, who is also director of Lakeland’s exercise science research.

“By looking 'under the hood' at individual motor units, we show that tiny changes in load meaningfully shift how the nervous system drives muscle, and that men and women don’t always get there the same way. That matters for how we design training and rehab at high intensities.”