Muscle force per cross-sectional area is inversely related with pennation angle in strength trained athletes

Shigeki Ikegawa1, Kazuo Funato, Naoya Tsunoda

  • 1Faculty of Human Health Science, Tokyo Metropolitan University, Tokyo, Japan. ikegawa@opal.famille.ne.jp

Related Concept Videos

Cross Product and Its Geometry01:27

Cross Product and Its Geometry

In three-dimensional space, any two non-zero vectors that are not parallel define a unique plane and geometrically outline a parallelogram. The cross product of these vectors results in a third vector that is orthogonal to the plane formed by the initial two. This vector not only encodes information about direction but also reflects important physical quantities in applied contexts.The orientation of the cross product vector is determined using the Right-Hand Rule. When the fingers of the right...
Fascicle Arrangement in Skeletal Muscles01:25

Fascicle Arrangement in Skeletal Muscles

Fascicles are bundles of muscle fibers in a skeletal muscle. Muscle fascicle arrangement is directly associated with the power and range of motion of various muscles. The configuration of these fascicles can vary, leading to different functional outcomes.
The four primary types of muscle based on fascicle arrangement are:
Cross-bridge Cycle01:26

Cross-bridge Cycle

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.
Motor Unit Stimulation01:20

Motor 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...
Two-Dimensional Force System01:20

Two-Dimensional Force System

A two-dimensional system in mechanical engineering involves the analysis of motion and forces in a plane. A two-dimensional force vector can be resolved into its components as:
Exercise and Muscle Performance01:27

Exercise and Muscle Performance

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...