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).
(concentric action) the 'true' form of contraction of a muscle in which it shortens against a load (which may be only that of gravity on the relevant body part), and so does positive work. Hence concentric exercise: that in which the principal agonists act concentrically.See also muscle contraction.alled also shortening contraction. Dupuytren's contraction Dupuytren's contracture. eccentric contraction contraction in the presence of a resistive force that results in elongation of a muscle, used to perform negative work or to decelerate a body part.