Stimulation of Denervated Muscle: What Do Isometric and Isotonic Recordings Tell Us?

摘要: In recording the contractile (or dynamic) properties of muscle. two standard sets conditions are commonly used. one, isometric set, muscle is held at a constant length and tension that develops measured. The other, namely isotonic involves allowing to shorten under load changes length. body, course, activity more complex, sometimes involving periods approximating or isotonic, but often shortening occurs varying load. When lifting weight, for example, arm muscles must first contract isometrically, developing sufficient overcome force gravity on weight (and arm). This will be followed by with greater than in phase because additional generated accelerate mass Only if speed movement reached, truly isotonic. As ended slowed, inertia exert opposite direction, which has opposed action antagonists. Finally, contraction hold up. Natural contractions also complex experimental recordings because, as example described above, activation not constant. A number motor units recruited, changing discharge rates different stages activity, according command signal from brain feedback many receptors.