Related Experiment Video
Updated: Jun 10, 2026
09:27
An Emerging Target Paradigm to Evoke Fast Visuomotor Responses on Human Upper Limb Muscles
Published on: August 25, 2020
EMG changes in agonist muscles during practice of a multijoint throwing skill
1Department of Kinesiology, Louisiana State University, Baton Rouge, Louisiana, U.S.A.
Summary
Practice improved throwing performance, but electromyography (EMG) amplitudes of primary arm muscles did not change. This suggests motor learning may involve other muscles or EMG analysis limitations.
Area of Science:
- Biomechanics
- Motor Control
- Sports Science
Background:
- Motor skill acquisition involves complex muscle coordination.
- Electromyography (EMG) is used to measure muscle activity during movement.
- Understanding muscle activation changes during practice is key to motor learning research.
Purpose of the Study:
- To investigate changes in electromyographic (EMG) amplitudes of agonist muscles during a planar multijoint throwing skill over practice.
- To determine if eccentric and concentric muscle activity amplitudes change with skill acquisition.
Main Methods:
- Eighteen participants practiced throwing a weighted ball in a horizontal plane.
- Electromyography (EMG) and kinematic data were collected during practice trials.
- Integrated EMG (IEMG) was analyzed for the triceps brachii and posterior deltoid during countermovement and throw phases.
Main Results:
- Throwing performance improved significantly over practice trial blocks.
- Despite performance improvements and changes in kinematic/kinetic variables, IEMG amplitudes of the triceps brachii and posterior deltoid did not change.
- Peak elbow angular velocity and elbow extensor moment work increased during the throw phase with practice.
Conclusions:
- Motor learning in this throwing skill may not involve increased EMG amplitudes of primary agonists.
- Changes in EMG activity might occur in auxiliary muscles rather than primary agonists.
- Limitations in EMG signal processing or skill acquisition research methodology could explain the lack of observed changes in primary agonist EMG amplitudes.
Related Concept Videos
01:24Muscle Coordination and Action
Muscle coordination is a complex and finely tuned process essential for smooth and purposeful movements like flexion, extension, adduction, abduction, and rotation. The human body orchestrates the actions of various muscles working in concert, each with a specific role. Four functional types describe how muscles work together: agonist, antagonist, synergist, and fixator.
Agonists
Agonist muscles, often called prime movers, are the primary muscles responsible for producing a specific movement.
Agonists
Agonist muscles, often called prime movers, are the primary muscles responsible for producing a specific movement.
01:20Motor 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...
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...
01:15Myasthenia Gravis: Diagnostic Tests
Myasthenia gravis is an autoimmune condition affecting neuromuscular transmission, causing generalized weakness in skeletal muscles. Initial diagnoses rely on patients' signs, symptoms, and medical history. The challenge lies in distinguishing myasthenia from other muscular dystrophies. An important diagnostic feature is the significant improvement of symptoms after administering anticholinesterase inhibitors.
The edrophonium test is a diagnostic tool for myasthenia gravis. It involves...
The edrophonium test is a diagnostic tool for myasthenia gravis. It involves...
01:28Disorders of the Skeletal Muscle
The clinical conditions affecting the skeletal muscle tissue are broadly categorized as musculoskeletal and neuromuscular disorders.
Musculoskeletal disorders
Musculoskeletal disorders involve injuries and conditions affecting the skeletal muscles and associated connective tissues. These disorders can arise from acute biomechanical stresses or chronic overuse and can occur across different age groups. Common injuries include sprains, fractures, and muscular strains, often resulting from...
Musculoskeletal disorders
Musculoskeletal disorders involve injuries and conditions affecting the skeletal muscles and associated connective tissues. These disorders can arise from acute biomechanical stresses or chronic overuse and can occur across different age groups. Common injuries include sprains, fractures, and muscular strains, often resulting from...