Achilles tendinitis is an inflammation of the tendon that connects the calf muscles to the heel bone. Achilles tendinitis is caused by small tears in the tendon from overuse or injury. It is most common in people who engage in high-impact exercise, particularly jogging, racquetball, and tennis. People at highest risk for this disorder are those with a shortened Achilles tendon, which can be due to an inborn structural abnormality or can be acquired after wearing high heels regularly. Such people tend to roll their feet too far inward when walking and bounce when they walk.
Heel spurs are calcium deposits that develop over time into a sharp bony growth under the heel bone.
They often result from improper foot movement during running or walking, poorly fitting shoes, and excessive body weight. As a spur develops the soft tissue in the heel becomes irritated and swells, putting pressure on the nerves and causing pain. Pain may increase with age as the fatty tissue on the bottom of the foot wears away. It should be noted, however, that plantar fascia, bursitis, stress fractures, and tarsal tunnel syndrome are more likely to be the cause of heel pain than spurs. Pronation is the normal motion that allows the foot to adapt to uneven walking surfaces and to absorb shock.