Tendons are found all over the body and form the tough yet flexible connections between muscles and bones. They cross over joints in order to produce movement and are susceptible to virtually any trauma involving the joint. Certain tendons are injured more frequently than others, and some physical activities are at higher risk for causing tendon injuries.
Tendonitis
"American Family Physician" reports that pre-existing tendonitis, or inflammation of a tendon, is a common cause of tendon injury. The inflammation from tendonitis is produced by microscopic rips in the tendon tissue. The resultant pain and swelling are a physiological mechanism to force rest and inactivity so the tendon heals properly. With tendinitis, the tendon is essentially already compromised, yet some people insist on working it out or pushing through the pain to continue activity. This added stress results in further damage to the tendon, and such damage can be quite severe. Larger rips or even avulsion may result, making long-term rehabilitation a necessity.
Forceful Movements
Since tendons cause limbs to move, their injury is most often a result of forceful movement in a limb joint. Of particular susceptibility is the Achilles tendon because it is the largest tendon in the body, and thus transmits the applied greatest force. It also spans two joints, both of which are used daily and for extended periods of time. Nearly 75 percent of Achilles tendon injuries are from sporting activities, where movements like jumping and running produce enormous tensile forces on the tendon, according to the Journal "Scandinavian Journal of Medicine and Science in Sports."
Repetitive Stress
In the last decade, the contribution of repetitive stress injury to the medical literature has increased dramatically. The National Institute of Neurological Disorders and Stroke warns that the upper body areas---especially the hands---are mostly susceptible to repetitive stress damage of tendons. The activities most often cited to result in repetitive stress-induced tendon damage include assembly line work, musical instrument playing, meatpacking, sewing, computer work, carpentry, gardening, golf and tennis.
Prior Injury
Another common factor leading to tendon injury is an incompletely healed tendon. As reported in a 2005 article in the journal "Manual Therapy," reinjury is the most common cause of hamstring injury, and usually is seen with athletes. This is a common cause of injury because already damaged tendons take weeks or months to heal completely and return to their full strength. Placing a full load on the tendon before it is back to its normal, healthy state, as might occur with strenuous sports activities, can cause the unhealed areas to fail. These unhealed and stressed areas rupture adjacent, normal areas since they must bear a higher load. The pain, swelling and immobility start over again, and this often becomes a repeating cycle of tendon reinjury, the article states.
Other
Muscles that are weakened or not ready to be stressed are another cause of tendon injury. If the joint is required to carry a load not suited for the muscle, hyperextension of the joint can cause excessive tendon stretching and subsequent injury. Infection in the tendon itself also can cause extensive injury. However, such injuries are rare and treated easily with antibiotics, notes MedlinePlus.
References
- "American Family Physician"; Common Conditions of the Achilles Tendon; M. Mazzone and T. McCue; May 2002
- "Scandinavian Journal of Medicine and Science in Sports"; Etiology and Pathophysiology of Tendon Ruptures in Sports; P. Kannus and A. Natri; April 1997
- "Manual Therapy"; The Management of Hamstring Injury: Part 1; W. Hoskins and H. Pollard; May 2005
- National Institute of Neurological Disorders and Stroke: NINDS Repetitive Motion Disorders Information Page
- MedlinePlus: Tenosynovitis
