Related Experiment Video
Updated: Jul 2, 2025
14:10
Isometric and Eccentric Force Generation Assessment of Skeletal Muscles Isolated from Murine Models of Muscular Dystrophies
Published on: January 31, 2013
33.0K
Conserved mammalian muscle mechanics during eccentric contractions
Roger W P Kissane1, Graham N Askew2
1Department of Musculoskeletal & Ageing Science, University of Liverpool, Liverpool, UK.
The Journal of Physiology
|February 24, 2024
Summary
Skeletal muscle
Area of Science:
- Biomechanics
- Muscle Physiology
- Mammalian Muscle Function
Background:
- Skeletal muscle's force-velocity relationship is crucial for power generation and energy absorption.
- The eccentric (lengthening) component of this relationship is poorly understood in mammalian muscles.
- Existing mathematical models for eccentric muscle behavior lack comprehensive data.
Purpose of the Study:
- To comprehensively assess the concentric and eccentric force-velocity relationships in four diverse mammalian muscles.
- To investigate how these relationships vary across a wide range of muscle masses and biomechanical functions.
- To provide data for improving mathematical models of eccentric muscle contractions.
Main Methods:
- Characterized force-velocity relationships using hyperbolic-linear (concentric) and hyperbolic (eccentric) equations.
- Measured the rate of force development during isovelocity lengthening ramps.
- Studied soleus, extensor digitorum longus, diaphragm, and digastric muscles from mice, rats, and rabbits.
- Investigated titin's role using mice with a titin deletion.
Main Results:
- Demonstrated conserved biphasic force response during active muscle lengthening across three orders of magnitude of mammalian muscle mass.
- Found consistent rates of relative force development during isovelocity lengthening ramps, despite variations in eccentric force-velocity curve.
- Showed that titin activation influences the biphasic force profile during muscle lengthening.
Conclusions:
- The biphasic force response during eccentric contractions is conserved across diverse mammalian muscles and body sizes.
- Titin activation plays a role in the eccentric force-velocity relationship.
- Rate of force development during muscle stretch is a reliable predictor for eccentric muscle forces and can inform Hill-type models.
Related Concept Videos
01:22Isotonic and Isometric Muscle Contractions
3.2K
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...
3.2K
01:20Excitation-Contraction Coupling in Skeletal Muscles
8.2K
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...
When an action...
8.2K
01:29Relaxation of Skeletal Muscles
3.2K
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....
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....
3.2K
01:20Motor Unit Stimulation
1.6K
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...
1.6K
01:16Actin and Myosin in Muscle Contraction
11.2K
Actin and myosin are contractile proteins that form the sarcomere found in skeletal muscle tissues for regulating muscle contraction. Actin, a globular contractile protein, interacts with myosin for muscle contraction. The skeletal tissue appears striped or striated under a microscope due to the repeated arrangement of contractile proteins actin and myosin along the length of myofibrils. Dark A bands and light I bands repeat along myofibrils, and the alignment of myofibrils in the cell causes...
11.2K
01:26Cross-bridge Cycle
117.5K
As muscle contracts, the overlap between the thin and thick filaments increases, decreasing the length of the sarcomere—the contractile unit of the muscle—using energy in the form of ATP. At the molecular level, this is a cyclic, multistep process that involves binding and hydrolysis of ATP, and movement of actin by myosin.
117.5K