在慢性力量训练的个体中,快速收缩期间运动单元放电率更高
Jakob Škarabot1, Andrea Casolo2, Thomas G Balshaw1,3
1School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, United Kingdom.
Journal of neurophysiology
|November 11, 2024
概括
与未经训练的人相比,力量训练的个体在快速收缩期间表现出更高的最大运动单元放电率. 然而,并没有观察到相对速度的力量发展差异,这表明训练可能会改变肌肉的特性.
科学领域:
- 神经肌肉生理学 神经肌肉生理学
- 运动科学 运动科学
- 人类运动 人类运动
背景情况:
- 动力单元 (MU) 放电特性在经过力量训练 (ST) 和未经训练 (UT) 个体的缓慢收缩期间是相似的.
- 在ST和UT个体之间,快速收缩期间的MU放电和最大力量发展速度 (RFD) 的差异尚不清楚.
研究的目的:
- 为了比较慢性ST和UT男性在快速,最大收缩期间的MU放电特征和RFD.
- 调查与力量训练状态相关的神经肌肉输出和力量生产能力的潜在差异.
主要方法:
- 研究了两个独立的慢性ST男性队列 (肘部曲器或膝盖伸缩器) 和UT对照组.
- 进行了最大的自愿快速收缩,以评估MU放电率和RFD,使用肌内电肌学和力传感器.
主要成果:
- 与UT个体相比,ST个体在最初150ms的快速肘部曲和膝盖延伸收缩中表现出更大的绝对RFD.
- 与UT个体相比,ST个体的 biceps brachii和 vastus lateralis 中观察到较高的初始MU放电率.
- 在快速收缩的早期阶段,ST个体的平均每秒MU排放数量更高.
结论:
- 慢性ST个体在快速收缩期间具有更高的最大运动单元放电率.
- 尽管ST个体的脊髓输出增加,相对RFD没有差异,这表明最大力增强或收缩性质的潜在适应.
相关概念视频
Motor Unit Stimulation
1.4K
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...
1.4K
Muscle Stimulation Frequency
2.0K
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...
2.0K
Motor Units
3.7K
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...
3.7K
Exercise and Muscle Performance
1.4K
Exercise induces a range of adaptations in muscle tissue, depending on the type and duration of activity. Such physical training can be broadly categorized into two types: endurance exercises and resistance exercises.
Endurance exercises
Endurance exercises involve running, swimming, or cycling, which require repetitive movements with low force output. When a person engages in endurance exercise, a few noticeable changes occur in their skeletal muscles. For instance, the number of capillaries...
Endurance exercises
Endurance exercises involve running, swimming, or cycling, which require repetitive movements with low force output. When a person engages in endurance exercise, a few noticeable changes occur in their skeletal muscles. For instance, the number of capillaries...
1.4K
Energy Supply for Muscle Contraction
2.9K
Skeletal muscle fibers have the unique ability to switch between rest and contraction states, using different sources of ATP for energy. The contraction cycle and Ca2+ transport back into the sarcoplasmic reticulum for relaxation require significant ATP. However, the ATP reserves in muscle fibers are limited and can only sustain contractions for a few seconds. Additional ATP production becomes necessary for prolonged contractions. As a result, muscle fibers generate ATP through various sources,...
2.9K
Relaxation of Skeletal Muscles
3.0K
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....
3.0K


