Related Experiment Video
Updated: Sep 23, 2026

Isolating Myofibrils from Skeletal Muscle Biopsies and Determining Contractile Function with a Nano-Newton Resolution Force Transducer
Published on: May 7, 2020
Mapping of movement in the isometrically contracting human soleus muscle reveals details of its structural and
Taija Finni1, John A Hodgson, Alex M Lai
1Department of Radiological Sciences, University of California, Los Angeles, California 90095-1527, USA.
Abstract:
It is becoming increasingly apparent that precise knowledge of the anatomic features of muscle, aponeurosis, and tendons is necessary for understanding how a muscle-tendon complex generates force and accomplishes length changes. This report presents both anatomic and functional data from the human soleus muscle acquired by using magnetic resonance imaging. The results show a strong relationship between the complex three-dimensional structure of the muscle-tendon system and the intramuscular distribution of tissue velocities during in vivo isometric contractions. The proximal region of the muscle is unipennate, whereas the midregion has a radially bipennate hemicylindrical structure, and the distal region is quadripennate. Tissue velocity mapping shows that the highest velocity regions overlay the aponeuroses connected to the Achilles tendon. These are located on the anterior and posterior surfaces of the muscle. The lowest velocities overlay the aponeuroses connected to the origin of the muscle and are generally located intramuscularly.
Related Concept Videos
Excitation-Contraction Coupling in Skeletal Muscles
When an action potential...
Actin and Myosin in Muscle Contraction
Muscles of the Leg that Move the Foot and Toes
Anterior Compartment
The anterior compartment includes muscles that contribute to the dorsiflexion of the foot. This compartment houses the tibialis anterior, extensor hallucis longus, and extensor digitorum longus muscles.
Isotonic and Isometric Muscle Contractions
Isotonic contractions
Isotonic contractions occur when a muscle changes length while the...
Microscopic Anatomy of Skeletal Muscles
The muscle sarcolemma is a plasma membrane enclosing each muscle cell that conducts electrical signals called action potentials. The sarcolemma extends into the cell to form T-tubules, ensuring the neural impulses are uniformly distributed across the entire muscle...
Structure and Organization of Smooth Muscles
Structure of smooth muscle cell
Smooth muscle cells are spindle-shaped with tapering ends and a...

