The effect of temporary exercising of a joint during an immobilization period: an experimental study on rabbits.

The right hind limbs of adult rabbits were immobilized for 5 weeks. The rabbits were then allowed to move freely for 8 weeks. The rabbits of the control group were immobilized uninterruptedly. In a second group of rabbits the plaster was removed during the immobilization period 6 days a week for 5 minutes for careful exercise and in a third group of rabbits, for violent exercise. The temporary careful exercise was of no benefit and was sometimes harmful, and the violent exercise was usually injurious for the immobilized knees as regards the stiffening, thickening and the development of radiologically detectable degenerative changes.