Related Experiment Video
Updated: Apr 3, 2026
An In Vitro Adult Mouse Muscle-nerve Preparation for Studying the Firing Properties of Muscle Afferents
Published on: September 24, 2014
Influence of prolonged static stretching on motor unit firing properties
Xin Ye1, Travis W Beck1, Nathan P Wages1
1Biophysics Laboratory, Department of Health and Exercise Science, University of Oklahoma, 1401 Asp Avenue. Room 104, Norman, Oklahoma, USA, 73019.
Introduction:
The purpose of this study was to examine the influence of a stretching intervention on motor control strategy of the biceps brachii muscle.
Methods:
Ten men performed twelve 100-s passive static stretches of the biceps brachii. Before and after the intervention, isometric strength was tested during maximal voluntary contractions (MVCs) of the elbow flexors. Subjects also performed trapezoid isometric contractions at 30% and 70% of MVC. Surface electromyographic signals from the submaximal contractions were decomposed into individual motor unit action potential trains. Linear regression analysis was used to examine the relationship between motor unit mean firing rate and recruitment threshold.
Results:
The stretching intervention caused significant decreases in y-intercepts of the linear regression lines. In addition, linear slopes at both intensities remained unchanged.
Conclusions:
Despite reduced motor unit firing rates following the stretches, the motor control scheme remained unchanged.
Related Concept Videos
01:20Motor 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...
01:22Muscle Stimulation Frequency
Wave summation
At low firing rates, motor neurons induce individual twitch contractions in muscle fibers. These twitches...
01:29Relaxation of Skeletal Muscles
When an action potential reaches the axon terminal, it depolarizes the membrane and opens voltage-gated sodium channels. Sodium ions enter the cell, further depolarizing the presynaptic membrane. This depolarization causes voltage-gated calcium channels to open....
01:22Isotonic and Isometric Muscle Contractions
Isotonic contractions
Isotonic contractions occur when a muscle changes length while...
01:24Generation of Action Potential in Skeletal Muscles
Like neurons, muscle cells are also regarded as excitable due to their capacity to change in response to stimuli, primarily due to voltage-gated ion channels embedded in their plasma membranes, which get activated by alterations in the...
01:25Smooth Muscle Contraction
The onset of contraction is triggered by an increase in calcium ions within the sarcoplasm, similar to the process in striated muscle. However, smooth muscles have a relatively smaller reservoir of the sarcoplasmic...