Achilles tendinitis is an overuse injury of the Achilles tendon – the thick band connecting your calf muscle to your heel bone. In simple terms, it means the tendon is irritated and inflamed from repeated stress.

For example, runners or athletes who repeat a toe-off motion can overload the tendon. Over time, this causes the tendon fibers to swell and hurt. It is not a strain from one sudden injury, but rather a gradual inflammatory condition from overworking the tendon.

What Are the Common Symptoms of Achilles Tendinitis?

• Heel/Achilles pain: You may feel a sharp or dull ache in the back of your heel or up the tendon, especially during or after activity.
  

• Morning stiffness: The tendon often feels stiff or sore on the first few steps after getting out of bed. Pain usually improves a bit as you move more during the day.
  

• Swelling or thickening: The Achilles tendon can look or feel swollen and tender. You might even notice it feels thicker than normal.

• Pain during exercise: Running, jumping, or other sports often trigger or worsen the tendon pain. Discomfort may increase with activity and linger the next day.

These symptoms usually affect the back of the lower leg, just above the heel. If you hear a sudden “pop” or have very sharp pain, that suggests a tendon tear.