Related Experiment Video
Updated: Apr 17, 2026

Versatility of Protocols for Resistance Training and Assessment Using Static and Dynamic Ladders in Animal Models
Published on: December 17, 2021
Motor unit control strategies of endurance- versus resistance-trained individuals
Trent J Herda1, Jacob A Siedlik1, Michael A Trevino1
1Neuromechanics Laboratory, Department of Health, Sport, and Exercise Sciences, University of Kansas, 1301 Sunnyside Avenue, Room 101BE, Lawrence, Kansas, 66045, USA.
Introduction:
We examined motor unit (MU) control properties of resistance-trained (RT) and endurance-trained (ET) individuals.
Methods:
Five RT (age 25 ± 4 years) and 5 ET (age 19 ± 1 years) subjects participated. Surface electromyography (EMG) data were recorded from the vastus lateralis during isometric trapezoid muscle actions at 40% and 70% of maximal voluntary contraction. Decomposition and wavelet transform techniques were applied to the EMG signals to extract the firing events of single MUs and EMG intensity across the frequency spectrum.
Results:
There were significant differences between RT and ET for the mean MU firing rate and derecruitment threshold versus recruitment threshold relationships and EMG intensity at various wavelet bands during the linearly increasing, steady force, and linearly decreasing segments of the trapezoid contraction.
Conclusions:
MU behavior is altered as a function of training status and is likely the result of differences in the physical properties of the MU.
More Related Videos
Related Concept Videos
Exercise and Muscle Performance
Endurance exercises
Endurance exercises involve running, swimming, or cycling, which require repetitive movements with low force output. When a person engages in endurance exercise, a few noticeable changes occur in their skeletal muscles. For instance, the number of capillaries...
Motor Units
Motor units come in different sizes, with smaller units...
Motor Units
Motor Unit Stimulation
The latent period of contraction marks the onset of excitation-contraction coupling, when the action potential propagates across the sarcolemma, preparing the muscle fibers for contraction. As the fibers enter the contraction phase, the...
Classification of Skeletal Muscle Fibers
Slow-Twitch Muscle Fibers
Slow oxidative, muscle fibers appear red due to large numbers of capillaries and high levels of...
Types of Skeletal Muscle Fibers
Fast-twitch fibers
Fast-twitch fibers, or Type II fibers, are designed for quick, powerful bursts of speed and strength. They reach peak tension within approximately 0.01 seconds following stimulation. Characterized by a large diameter and densely packed myofibrils, these fibers contain...

