Jumpers Knee is the common term for Patella Tendonitis. Jumpers Knee occurs gradually if jumping and landing type activities are practised too much, because the strain on the Patella Tendon becomes too great and microscopic damage develops in the tissue that makes up the tendon. Patella Tendinopathy is usually characterised by degeneration of the tendon, whereas Patella Tendonitis is characterised by inflammation of the patella tendon, which is much rarer.