Related Experiment Video
Updated: Jan 29, 2026
08:29
In vivo Measurement of Knee Extensor Muscle Function in Mice
Published on: March 4, 2021
5.6K
Aging and Strength Training Influence Knee Extensor Intermuscular Coherence During Low- and High-Force Isometric
Simon Walker1, Janne Avela1, Jan Wikgren2
1Neuromuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland.
Frontiers in Physiology
|February 8, 2019
Summary
Younger adults exhibit higher intermuscular coherence than older adults, even with similar strength. Strength training impacts this coherence differently across age groups, but its functional role in strength and steadiness remains unclear.
Area of Science:
- Neuromuscular Physiology
- Aging Research
- Motor Control
Background:
- Aging reduces force production and steadiness, though training can improve these.
- Intermuscular coherence (EMG-EMG coupling) may reflect common neural input but its role in aging and training is unclear.
- Understanding neural control differences between young and old is crucial for targeted interventions.
Purpose of the Study:
- To investigate age-related differences in knee extensor intermuscular coherence.
- To examine the effects of strength training on intermuscular coherence in young and older adults.
- To explore the functional significance of intermuscular coherence for maximal strength and force steadiness.
Main Methods:
- Compared previously sedentary young (18-30 yrs) and older (67-73 yrs) adults before and after a 14-week strength training program.
- Measured maximal voluntary contraction (MVC) and force steadiness (at 20% and 70% MVC) of knee extensors.
- Analyzed intermuscular coherence between vastus lateralis and medialis EMG signals across different contraction intensities (20%, 70%, 100% MVC).
Main Results:
- Pre-training MVC and force steadiness were similar, but young adults showed higher intermuscular coherence at 20% and 70% MVC (8-14 Hz and 16-30 Hz bands).
- Both groups improved MVC post-training, with greater gains in young adults. Young adults showed increased coherence (40-60 Hz) at 70% MVC, while older adults decreased coherence (8-14 Hz) at 100% MVC.
- Age-related differences in coherence existed even with similar baseline performance, and coherence did not predict strength or steadiness.
Conclusions:
- Age-related differences in neural control, reflected by intermuscular coherence, are present even when maximal strength and steadiness are comparable.
- Strength training differentially alters intermuscular coherence in young and older adults, suggesting distinct adaptations in motor unit control.
- The functional role of intermuscular coherence in modulating maximal force production and force steadiness requires further investigation.
More Related Videos
14:10Isometric and Eccentric Force Generation Assessment of Skeletal Muscles Isolated from Murine Models of Muscular Dystrophies
Published on: January 31, 2013
33.9K
07:30Muscle Imbalances: Testing and Training Functional Eccentric Hamstring Strength in Athletic Populations
Published on: May 1, 2018
15.9K
Related Concept Videos
01:22Isotonic and Isometric Muscle Contractions
7.0K
Two primary types of muscle contractions are isotonic and isometric, each serving unique functions and involving distinct mechanisms. Both isotonic and isometric contractions are integral to the body's complex system of movement and stability. Isotonic exercises contribute significantly to functional strength and movement, while isometric contractions are crucial for maintaining posture and joint stability.
Isotonic contractions
Isotonic contractions occur when a muscle changes length while...
Isotonic contractions
Isotonic contractions occur when a muscle changes length while...
7.0K
03:13Intermolecular Forces
70.8K
Atoms and molecules interact through bonds (or forces): intramolecular and intermolecular. The forces are electrostatic as they arise from interactions (attractive or repulsive) between charged species (permanent, partial, or temporary charges) and exist with varying strengths between ions, polar, nonpolar, and neutral molecules. The different types of intermolecular forces are ion–dipole, dipole–dipole, hydrogen bonds, and dispersion; among these, dipole–dipole, hydrogen...
70.8K
01:23Knee Joint
3.2K
The knee joint is the most complicated joint in the body. It consists of three articulations– two tibiofemoral and one patellofemoral. As is characteristic of synovial joints, the knee joint has a thin articular capsule that partially surrounds this joint cavity. Additionally, several ligaments, muscles, and cartilaginous structures support the movement of the knee.
A total of seven ligaments support the knee joint. The patellar ligament, which is also attached to the quadriceps femoris...
A total of seven ligaments support the knee joint. The patellar ligament, which is also attached to the quadriceps femoris...
3.2K
03:05Acid Strength and Molecular Structure
33.0K
Binary Acids and Bases
In the absence of any leveling effect, the acid strength of binary compounds of hydrogen with nonmetals (A) increases as the H-A bond strength decreases down a group in the periodic table. For group 17, the order of increasing acidity is HF < HCl < HBr < HI. Likewise, for group 16, the order of increasing acid strength is H2O < H2S < H2Se < H2Te. Across a row in the periodic table, the acid strength of binary hydrogen compounds increases with increasing...
In the absence of any leveling effect, the acid strength of binary compounds of hydrogen with nonmetals (A) increases as the H-A bond strength decreases down a group in the periodic table. For group 17, the order of increasing acidity is HF < HCl < HBr < HI. Likewise, for group 16, the order of increasing acid strength is H2O < H2S < H2Se < H2Te. Across a row in the periodic table, the acid strength of binary hydrogen compounds increases with increasing...
33.0K
01:15Muscle Contraction
96.2K
96.2K
01:10Muscle Contraction
8.9K
In skeletal muscles, acetylcholine is released by nerve terminals at the motor endplate—the point of synaptic communication between motor neurons and muscle fibers. The binding of acetylcholine to its receptors on the sarcolemma allows entry of sodium ions into the cell and triggers an action potential in the muscle cell. Thus, electrical signals from the brain are transmitted to the muscle. Subsequently, the enzyme acetylcholinesterase breaks down acetylcholine to prevent excessive...
8.9K