Overuse or repeated movements during sports, work, or other activities. In sports, a change in how long, intensely, or often you exercise can cause microtears in the tendon. These tears are unable to heal quickly and will eventually cause pain. A change in your environment, such as going from a flat surface to a hill or from a dirt road to a paved road, can also cause these tears.
Injury from repeated push-offs or a stop-and-go motion. These injuries are common in such activities as running, basketball, tennis, or ballet dancing.
Sudden, forceful motion that stresses the calf muscle. This can happen during an intense athletic activity or even during simple running or jumping, especially in middle-aged adults. A rupture most often occurs in sports such as basketball, racquet sports (including tennis), soccer, and softball.
Overstretching the tendon during any activity when the tendon is already damaged because of Achilles tendinopathy or another condition.