Hyperactive definition, unusually or abnormally active: a company's hyperactive growth; the child's hyperactive imagination. See more.
muscle contraction. the process of force-generation in the fibres of any class of muscle, by the interaction of myosin head-groups in the thick filaments with actin molecules in one of the immediately neighbouring thin filaments.oncentric muscle contraction acceleration force generated within contracting agonist muscle tissue, by actin/myosin interaction; agonist muscle force overcomes antagonist muscle resistance, creating a net reduction in length of agonist muscle (see entry above).
The termination of muscle contraction is followed by muscle relaxation, which is a return of the muscle fibers to their low tension-generating state.n contrast, a muscle contraction is isotonic if muscle length changes but the muscle tension remains the same. Furthermore, if the muscle length shortens, the contraction is concentric. But if the muscle length lengthens, then the contraction is eccentric.