This article is from the Aerobics Fitness FAQ, by email@example.com (Robles) with numerous contributions by others.
Any "-itis" condition refers to inflammation or irritation.
In the cases of tendonitis, arthritis, and bursitis, the sites of
inflammation are the tendons, joints, and bursae (fluid-filled
sacs provided cushioning between tendons and bones), respectively.
Again, any of these conditions should involve a physician
referral. Tendonitis and bursitis are common overuse injuries,
and rehabilitation will generally involve rest, and enhancing
flexibility and strength of all muscles surrounding the joints
near the area in question.
Arthritis can be caused by two distinct disease processes -
osteoarthritis is essentially "wear and tear" on joints, in which
the cartilage covering the articulating surfaces of the bones
becomes worn, and the joint reacts, often by swelling and
filling with fluid. It can become quite tender, and
motion can become difficult.
Rheumatoid arthritis is an autoimmune disorder in which the
body launches an attack on its own joint tissues. While much
less common than osteoarthritis, it can be severely debilitating.
Rehabilitation for arthritis generally involves activities
that are low-impact in nature, and strengthening exercises.
Activities are carried out through a "pain-free range of motion"
(ROM limited by the onset of discomfort), and no activity is
recommended during periods of active inflammation.