Athletes and Older People Are More Likely to Have It
Achilles tendonitis is usually a repetitive strain injury. A repetitive strain injury is an injury to the muscles or tendons that is caused by repetitive overuse of certain body parts or muscle or tendon groups.
Although Achilles tendonitis can affect anybody, athletes are more likely to develop the condition.  The condition has cut the professional careers of many soccer, basketball, and football players short. Athletes perform a lot of activities that require the repetitive use of their muscles and tendons. Activities such as running, jumping, dribbling, and other aggressive maneuvers that are a part of many sports put extra strain on the Achilles tendon.
Age is also another important factor in the development of Achilles tendonitis. The tendons weaken and wear out naturally with age. If you begin to play active sports or engage more often in activities later in life, you are more likely than the average person to develop this problem.