Achilles Tendonitis
What is Achilles tendonitis?
The Achilles tendon is the largest tendon in your body. It is a strong band of tissue that connects the calf muscles at the back of your lower leg to your heel bone. It powers everyday movements such as walking, climbing stairs, running, and pushing up onto the toes. Because this tendon absorbs high forces with each step, it is vulnerable to irritation. Achilles tendonitis refers to inflammation and irritation of this tendon, typically developing when the tendon is stressed more than it can comfortably handle. The condition can affect people of any age or activity level, but it is particularly common in runners, court-sport athletes, and individuals who make sudden changes to their exercise routines.
Most cases begin with overuse. Increasing mileage, pace, hills, or training frequency too quickly can strain the tendon before it has time to adapt. Tight calf muscles shift more load to the Achilles, especially during uphill activity or when starting after periods of inactivity.
Foot mechanics also matter. Flat feet with over-pronation or high arches can alter the way forces travel through the ankle and place extra stress on the tendon with each step. Footwear plays a role as well. Worn-out shoes or shoes with poor heel and arch support can increase the risk. Weekend athletes who exercise vigorously after being mostly inactive during the week are also at risk.
Age-related changes in the tendon are another contributing factor. As people get older, the tendon loses some elasticity and strength, making it more likely to become irritated or injured. Finally, training on hard or uneven surfaces, particularly without proper conditioning, can trigger the onset of symptoms.
Achilles tendonitis usually develops gradually rather than suddenly. The most common symptom is pain along the back of the heel or lower calf. This pain often feels worse in the morning or after periods of rest but may improve slightly once the tendon is warmed up. With continued activity, the pain typically returns and may become sharper. Swelling around the tendon is common, and the area may feel tender to the touch. Over time, the tendon itself can thicken, and stiffness can limit the ability to move the ankle freely.
Some people experience sharp pain when climbing stairs, running, or pushing off the toes. If the condition worsens, pain can become constant and interfere with daily activities like walking. In rare cases, untreated tendonitis can lead to a partial or complete rupture of the tendon, which causes sudden severe pain and requires surgical treatment.
Diagnosis begins with a detailed medical history and physical exam. Your OANC orthopedic specialist will ask about your symptoms, activity levels, footwear, and any recent changes in exercise routines. During the exam, the doctor will check for swelling, tenderness, and how well the foot and ankle move.
In many cases, this exam is enough to make the diagnosis. If more detail is needed, imaging tests may be used. X-rays do not show tendons but can help rule out bone conditions such as heel spurs. Ultrasound can reveal inflammation, thickening, or small tears in the tendon in real time. An MRI offers even more detailed images and can show the extent of tendon damage if the condition is severe. Early and accurate diagnosis is important, as untreated tendonitis can lead to long-term degeneration of the tendon fibers. This is more difficult to treat and takes longer to recover from.
Mild soreness after exercise is common, but pain that does not go away after a few days should be taken seriously. You should see a doctor if you have persistent pain in the back of the heel or calf, significant swelling or stiffness, or difficulty walking normally. A sudden sharp pain combined with an inability to push off the foot may signal a tendon rupture and requires immediate medical attention. Getting care early can prevent the condition from worsening and help you return to normal activities more quickly.
Achilles tendonitis is a common overuse injury that causes pain, swelling, and stiffness in the back of the leg near the heel. It develops when the tendon is placed under too much strain, whether from sports, poor footwear, abnormal foot structure, or sudden increases in activity. Diagnosis usually involves a physical exam and sometimes imaging tests to confirm the condition and rule out other problems.
At Orthopedic Associates of Northern California, our team of orthopedic specialists has extensive experience diagnosing and treating foot and ankle conditions like Achilles tendonitis. If you are experiencing persistent heel pain or stiffness that is limiting your activities, scheduling an appointment with our team is the best way to get an accurate diagnosis and begin the path to recovery.
