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).
Introduction. A muscle cramp is a sudden, involuntary, painful contraction of a muscle or part of it, self-extinguishing within seconds to minutes and is often accompanied by a palpable knotting of the muscle.The cramp contractions are associated with repetitive firing of motor unit action potentials. cramp can be distinguished from spasms (i.e., any involuntary and abnormal muscle contraction, regardless of whether it is painful) or generic painful contractions based on clinical and electrophysiological criteria. For example, muscle contractures resemble cramps because they are involuntary and painful.