MRI of a knee. MRIs employ powerful magnets which produce a strong magnetic field that forces protons in the body to align with that field. When a radiofrequency current is then pulsed through the patient, the protons are stimulated, and spin out of equilibrium, straining against the pull of the magnetic field.
Noun. 1. aestivation - (zoology) cessation or slowing of activity during the summer; especially slowing of metabolism in some animals during a hot or dry period. estivation. zoological science, zoology-the branch of biology that studies animals.
Muscle coactivation is the simultaneous activation of agonist and antagonist muscles acting on the same joint and. has, among others, the mechanical effect of making a joint stiffer. Joint stiffness, in turn, is influenced by the velocity. of movement being higher over the course of faster movements (1).