阿基里斯肌的形态-机械参数与三肌体 surae 运动单元的发射特性有关
Ignacio Contreras-Hernandez1, Michail Arvanitidis1, Deborah Falla1
1Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom.
Journal of neurophysiology
|September 4, 2024
概括
这项研究表明,发动机单元的发射特性,如放电率,影响阿基里斯肌的刚性和长度,特别是在低力收缩期间. 这些发现强调了神经控制和肌力学之间的收缩强度依赖的联系.
科学领域:
- 生物力学 生物力学
- 神经科学是一个神经科学.
- 人类运动科学科学 人类运动科学
背景情况:
- 高密度表面电肌图 (HD-sEMG) 和超声波成像已经对运动单元活动和肌肉收缩有了更深入的了解.
- 关于机动单元发火特性与肌机械性质之间的联系的研究有限.
研究的目的:
- 为了研究三体外运动单元发火特性和阿基里斯肌 (AT) 的形态机械特征之间的关系.
- 探索动力单元放电率 (DR) 和间隙间变化 (COV) 与AT刚度和长度的关系.
主要方法:
- HD-sEMG用于评估在10%和40%的最大自发收缩 (MVC) 时的同位体脚部屈曲期间的动力单元发射特性 (DR,COVisi) 和发射扭矩关系.
- B模式超声波和剪切波弹性学测量了AT的形态机械性质 (长度,厚度,横截面积,静止硬度).
- 多重线性回归分析了动力单元发射和AT属性之间的关联.
主要成果:
- 在10%的MVC时,三肌 surae DR解释了41.7%的静止AT度变异.
- 在10%的MVC时,单肌 (SO) 的COVisi预测了AT长度变异的30.4%.
- 在40%的MVC时,中部胃角肌 (MG) 和SO肌的COVisi解释了AT长度变异的48.7%. 发动机单元-扭矩关系与AT形态机械参数没有关联.
结论:
- 新的证据表明,三肌肌肉运动单元发射参数和阿基里斯肌形态-机械性质之间的收缩强度依赖关系.
- 平均放电速率和运动单元发射的变化与阿基里斯肌的休息度和长度有关,为肌单元的神经控制提供了洞察力.
相关概念视频
01:20Motor Unit Stimulation
1.5K
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...
1.5K
01:20Excitation-Contraction Coupling in Skeletal Muscles
8.0K
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...
8.0K
01:13Motor Units
3.8K
The motor unit is a fundamental component of the neuromuscular system and plays a crucial role in coordinating muscle contractions. It consists of a somatic motor neuron, which connects and controls multiple skeletal muscle fibers, forming a single functional segment. The axon of the motor neuron branches out and establishes synaptic connections known as neuromuscular junctions with individual muscle fibers within the motor unit.
Motor units come in different sizes, with smaller units...
Motor units come in different sizes, with smaller units...
3.8K
01:22Muscle Stimulation Frequency
2.1K
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...
Wave summation
At low firing rates, motor neurons induce individual twitch contractions in muscle fibers. These twitches...
2.1K