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Isolytic contraction is when a muscle contracts while external forces cause it to lengthen. [1] For example, during a controlled lowering of the weight in a biceps curl , the biceps are undergoing isolytic contraction.
An isometric exercise is an exercise involving the static contraction of a muscle without any visible movement in the angle of the joint. The term "isometric" combines the Greek words isos (equal) and -metria (measuring), meaning that in these exercises the length of the muscle and the angle of the joint do not change, though contraction ...
The stretch reflex operates as a feedback mechanism to control muscle length by causing muscle contraction. In contrast, the tendon reflex operates as a negative feedback mechanism to control muscle tension. Although the tendon reflex is less sensitive than the stretch reflex, it can override the stretch reflex when tension is great, for ...
In concentric contraction, muscle tension is sufficient to overcome the load, and the muscle shortens as it contracts. [8] This occurs when the force generated by the muscle exceeds the load opposing its contraction. During a concentric contraction, a muscle is stimulated to contract according to the sliding filament theory. This occurs ...
According to his theory, filament sliding occurs by cyclic attachment and detachment of myosin on actin filaments. Contraction occurs when the myosin pulls the actin filament towards the centre of the A band, detaches from actin and creates a force (stroke) to bind to the next actin molecule. [ 32 ]
Cadaveric spasm, also known as postmortem spasm, instantaneous rigor mortis, cataleptic rigidity, or instantaneous rigidity, is a rare form of muscular stiffening that occurs at the moment of death and persists into the period of rigor mortis. [1]
[1] [2] [3] The calcium ion concentration in sarcoplasm is also a special element of the muscle fiber; it is the means by which muscle contractions take place and are regulated. [ 4 ] [ 5 ] The sarcoplasm plays a critical role in muscle contraction as an increase in Ca 2+ concentration in the sarcoplasm begins the process of filament sliding.
During muscle contraction, tropomyosin shifts to expose the myosin-binding site on an actin filament, allowing the interaction between actin and myosin microfilaments to occur. The initiation of contraction involves calcium ions binding to troponin, prompting a reaction that displaces tropomyosin from the actin filament binding sites.