Related Experiment Video

Updated: Feb 17, 2026

Method to Measure Tone of Axial and Proximal Muscle
10:41

Method to Measure Tone of Axial and Proximal Muscle

Published on: December 14, 2011

18.0K

Spasm and flexion-relaxation phenomenon response to large lifting load during the performance of a trunk

Yanjun Ma1, Xinhai Shan2

  • 1Biomechanics Laboratory, College of Physical Education, Shandong Normal University, 88 Wenhua East Road, Jinan, Shandong, 250014, People's Republic of China.

BMC Musculoskeletal Disorders
|December 1, 2017
PubMed
Abstract

Keywords:
Erector spinaeLifting loadLow back painMuscular intensityTrunk flexion-extension

More Related Videos

Muscle Function Obtained with Motion Mode Ultrasound and Surface Electromyography during Core Endurance Exercise09:21

Muscle Function Obtained with Motion Mode Ultrasound and Surface Electromyography during Core Endurance Exercise

Published on: August 25, 2022

3.8K
An Instrumented Pull Test to Characterize Postural Responses12:18

An Instrumented Pull Test to Characterize Postural Responses

Published on: April 6, 2019

11.5K

Related Concept Videos

Somatic Spinal Reflexes01:22

Somatic Spinal Reflexes

Somatic spinal reflexes are rapid, involuntary muscular responses to external stimuli that involve the somatic musculature and the spinal cord.
One of the most well-known somatic spinal reflexes is the stretch reflex, which is activated by the sudden stretching of a muscle. This reflex involves the activation of specialized sensory receptors called muscle spindles, which are located in the muscle tissue and detect changes in the length and speed of muscle contractions. When a muscle is suddenly...
5.5K
Relaxation of Skeletal Muscles01:29

Relaxation of Skeletal Muscles

The period of muscle contraction primarily influences the duration of stimulation at the neuromuscular junction (NMJ), the presence of free calcium ions in the sarcoplasm, and the availability of energy or ATP to support contractions.
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....
6.1K
Muscle Stimulation Frequency01:22

Muscle Stimulation Frequency

The contraction strength of muscles is regulated by motor neurons, which modulate the frequency of action potentials dispatched to the motor units based on the body's requirements. This process of varying the muscle stimulation frequency allows muscles to contract with a force that is precisely tailored to the needs of the moment, whether lifting a feather or a heavy box.
Wave summation
At low firing rates, motor neurons induce individual twitch contractions in muscle fibers. These twitches...
4.7K
Motor Unit Stimulation01:20

Motor Unit Stimulation

When the neuron of a motor unit fires an action potential, it triggers a series of events, leading to a twitch contraction in the muscle fibers. The process of excitation-contraction coupling is crucial in relaying the action potential to the muscle fibers.
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...
4.0K
Muscles of the Vertebral Column01:27

Muscles of the Vertebral Column

The back muscles that lie deep into the thoracolumbar fascia are called intrinsic or true back muscles. These muscles are divided into four layers: superficial, intermediate, deep, and deepest layers.
Superficial Layer:
The superficial layer consists primarily of the splenius muscles, which include the splenius capitis and splenius cervicis. These muscles are mainly responsible for the head and cervical spine movements, including extension, rotation, and lateral bending. The splenius capitis...
3.4K
Excitation-Contraction Coupling in Skeletal Muscles01:20

Excitation-Contraction Coupling in Skeletal Muscles

Excitation-contraction coupling is a series of events that occur between generating an action potential and initiating a muscle contraction. It occurs at the triad, a structure found in skeletal muscle fibers that comprise a T-tubule and terminal cisternae of the sarcoplasmic reticulum on each side. These triads are visible in longitudinally sectioned muscle fibers. They are typically located at the A-I junction — the junction between the A and I bands of the sarcomere.
When an action...
15.7K