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).
Skeletal muscle contractions can be broadly separated into twitch, summation, and tetanic contractions. In a twitch contraction, a single action potential, whether from a motor neuron or from within the muscle, causes the muscle fiber to produce a single contraction and relaxation cycle called a twitch.uscle contractions can be described based on two variables: length and tension. A muscle contraction is described as isometric if the muscle tension changes but the muscle length remains the same. In contrast, a muscle contraction is isotonic if muscle length changes but the muscle tension remains the same.