Most tendon injuries are the result of gradual wear and tear to the tendon from overuse or ageing. Anyone can have a tendon injury. People repeat the same motion (over and over) in their jobs, sports, or daily activities are more likely to damage a tendon.
Your tendons are designed to withstand high, repetitive loading, however, on occasions, when the load being applied to the tendon is too great for the tendon to withstand, the tendon begins to become stressed.
When tendons become stressed, they sustain small micro tears (otherwise known as lesions). These tears encourage inflammatory chemicals and swelling and heal quickly if managed appropriately.
However, if a load (pressure) is continually applied to a tendon, the tearing can be faster than the rate at which the tendon heals. The damage will progressively become worse, causing pain and dysfunction. The result is a tendinopathy or tendinosis.
Researchers suggest that tendinopathies start out as very small injuries (microtrauma), usually associated with physically intensive sport or leisure activities, which worsen over time to cause a tendinopathy.