Achilles Tendinitis: Symptoms, Treatment & Recovery Guide

What Is Achilles Tendinitis?

Achilles tendinitis is an overuse injury affecting the Achilles tendon—the large tendon connecting your calf muscles to your heel bone. It causes pain, swelling, and stiffness in the back of the heel, typically developing when you increase physical activity more than usual. Despite its name, it's technically a degenerative condition (tendinopathy) rather than inflammation.

The Achilles tendon is the strongest and largest tendon in the human body, capable of withstanding forces of up to 12 times your body weight during activities like running and jumping. However, this remarkable strength also makes it susceptible to overuse injuries when placed under repetitive stress without adequate recovery time.

Achilles tendinitis develops gradually through a process of repeated micro-damage to the tendon fibers. When the tendon is stressed faster than it can repair itself, the collagen fibers that make up the tendon begin to break down and become disorganized. This leads to the characteristic pain, swelling, and weakness associated with the condition. Understanding this mechanism is important because it explains why rest and gradual rehabilitation are essential for recovery.

The condition typically affects the middle portion of the tendon, known as mid-portion Achilles tendinopathy, which occurs 2-6 centimeters above where the tendon attaches to the heel bone. Less commonly, it can affect the area where the tendon inserts into the heel, called insertional Achilles tendinopathy. This distinction matters because insertional tendinopathy can be more challenging to treat and may involve the heel bone itself.

What Happens in the Body?

Despite being called "tendinitis" (suggesting inflammation), research has shown that chronic Achilles tendon problems involve more degenerative changes than inflammatory ones. The tendon undergoes a process called tendinosis, where the normal parallel arrangement of collagen fibers becomes disrupted and disorganized. Blood vessels and nerve endings may grow into the damaged areas, which paradoxically can contribute to ongoing pain.

The tendon may also thicken as the body attempts to repair the damage, creating a nodular swelling that's often visible and palpable a few centimeters above the heel. This thickening represents scar tissue formation and is a sign that the tendon's structure has been compromised. While concerning in appearance, this does not mean the tendon will rupture—in fact, ruptures typically occur in tendons that haven't shown previous symptoms of tendinopathy.

Who Is Most at Risk?

Achilles tendinitis can affect anyone, but certain groups face higher risk. Runners and athletes who perform repetitive jumping are particularly susceptible, with lifetime prevalence reaching up to 52% in runners. Middle-aged adults (30-50 years) are most commonly affected as tendon elasticity naturally decreases with age. Other risk factors include obesity, tight calf muscles, flat feet, and certain medications like fluoroquinolone antibiotics which can weaken tendon tissue.

What Are the Symptoms of Achilles Tendinitis?

The main symptoms of Achilles tendinitis include pain above the heel that worsens with activity, morning stiffness in the ankle and calf, swelling along the tendon, and tenderness when pressing on the affected area. Pain typically starts mild and gradually worsens over days or weeks if activity continues.

The hallmark symptom of Achilles tendinitis is pain in the back of the heel and lower calf. This pain has some characteristic patterns that help distinguish it from other conditions. Initially, you may notice discomfort only at the beginning of exercise that seems to improve as you warm up, then returns after you stop. This "warm-up phenomenon" is typical of early-stage tendinopathy and occurs because increased blood flow temporarily improves symptoms.

As the condition progresses, pain may become more constant and affect daily activities. Walking up stairs, rising onto your toes, or even wearing certain shoes can trigger discomfort. The pain is usually described as an aching or burning sensation, though some people experience sharp pain with certain movements. Understanding how your pain behaves can help your healthcare provider determine the severity of your condition and appropriate treatment approach.

Morning stiffness is another common complaint. Upon waking, the Achilles tendon and surrounding structures feel tight and uncomfortable. This stiffness typically improves within 30 minutes to an hour of gentle movement but may persist longer in more severe cases. The stiffness occurs because the tendon contracts slightly during rest and the damaged tissue has reduced flexibility compared to healthy tendon.

Visible Signs of Achilles Tendinitis

In addition to pain and stiffness, you may notice visible changes to the affected area. Swelling along the tendon is common, appearing as a thickened, nodular area typically located 2-6 centimeters above the heel bone. This swelling represents the body's attempt to repair the damaged tissue and may be warm to the touch during acute phases.

Some people notice that the affected leg's calf appears slightly smaller than the unaffected side. This occurs because pain causes you to use the leg less, leading to some muscle wasting over time. The skin over the tendon may also appear slightly red in acute cases, though significant redness and warmth should prompt evaluation for other conditions like infection.

When Symptoms May Indicate Something More Serious

While most Achilles pain is due to tendinitis, certain symptoms warrant immediate medical attention. A sudden, severe pain accompanied by a "pop" or "snap" sensation may indicate a partial or complete tendon rupture. If you cannot push up onto your toes or notice a gap in the tendon, seek emergency care. Similarly, symptoms of infection—including significant redness, warmth, fever, or spreading pain—require prompt evaluation.

What Causes Achilles Tendinitis?

Achilles tendinitis is primarily caused by overuse—putting repetitive stress on the tendon without adequate recovery time. Common triggers include sudden increases in exercise intensity or duration, tight calf muscles, improper footwear, exercising on hard or uneven surfaces, and age-related tendon changes. Being overweight and certain medications can also increase risk.

The most common cause of Achilles tendinitis is the "too much, too soon" phenomenon. This occurs when you suddenly increase your physical activity level without giving your body time to adapt. For example, starting an intense running program after being sedentary, dramatically increasing your weekly mileage, or adding hill training without gradual progression can all overwhelm the tendon's capacity to repair itself. The tendon can typically handle significant loads, but it needs time to strengthen in response to new demands.

Training errors account for approximately 60-70% of Achilles tendinopathy cases in athletes. These errors include not only volume increases but also changes in training surface, footwear, or technique. Running on hard surfaces like concrete places more stress on the tendon than softer surfaces like trails or tracks. Similarly, worn-out running shoes lose their ability to absorb shock, transferring more force to the tendon with each step.

Biomechanical factors play a significant role in tendinitis development. Tight calf muscles (gastrocnemius and soleus) increase tension on the Achilles tendon during walking and running. Limited ankle flexibility forces the tendon to work harder to achieve normal movement. Foot structure issues—such as flat feet (overpronation) or high arches (supination)—can alter how force is distributed through the tendon, creating areas of concentrated stress.

Age-Related Changes

As we age, our tendons undergo natural changes that increase vulnerability to injury. Collagen production decreases, and the remaining collagen fibers become less organized and more brittle. Blood supply to the tendon also diminishes, reducing its ability to heal after microtrauma. These changes explain why Achilles tendinopathy peaks in the 30-50 age range—old enough for degenerative changes to begin, but still active enough to stress the tendon significantly.

The tendon's response to loading also slows with age. Younger tendons can typically adapt to increased demands within 2-3 weeks, while older tendons may require 6-8 weeks to achieve the same adaptation. This means older individuals need to progress exercise programs more gradually and allow more recovery time between intense sessions.

Other Contributing Factors

Obesity significantly increases Achilles tendinitis risk because excess body weight amplifies the force transmitted through the tendon with every step. Studies show that for every additional kilogram of body weight, the Achilles tendon experiences approximately 4-6 additional kilograms of force during walking. This mechanical overload accelerates tendon degeneration and slows healing.

Certain medications have been linked to increased tendon problems. Fluoroquinolone antibiotics (such as ciprofloxacin and levofloxacin) are the most well-documented, with studies showing they can weaken tendon structure and increase rupture risk. The mechanism involves inhibition of collagen synthesis and increased tendon cell death. If you're prescribed these antibiotics and have risk factors for tendon problems, discuss alternatives with your healthcare provider.

What Can I Do to Treat Achilles Tendinitis at Home?

Home treatment for Achilles tendinitis includes rest and activity modification (avoiding running and jumping), applying ice for 15-20 minutes several times daily, using supportive footwear with heel lifts, taking over-the-counter pain relievers if needed, and performing gentle calf stretches. Most mild cases improve within 1-2 weeks with these measures.

The foundation of Achilles tendinitis treatment is relative rest—not complete immobilization, but smart modification of activities to reduce tendon stress while maintaining fitness. This means temporarily avoiding high-impact activities like running, jumping, and stair climbing while the tendon heals. However, complete rest isn't beneficial either, as some controlled loading actually helps tendon healing by stimulating repair processes.

During the acute phase, you can maintain cardiovascular fitness through low-impact alternatives. Swimming is excellent because water buoyancy eliminates impact stress entirely. Cycling places minimal load on the Achilles tendon and can usually be performed pain-free. Elliptical training offers another option, though some people find it aggravating if the machine requires significant toe push-off. The key is listening to your body—if an activity causes pain in the tendon, stop and try something else.

Ice application can help manage pain and any residual inflammation, particularly in early or acute phases. Apply an ice pack wrapped in a towel to the affected area for 15-20 minutes, several times daily, especially after any activity. Avoid applying ice directly to the skin to prevent frostbite. While ice provides symptomatic relief, it's worth noting that research on its effectiveness for tendon healing is mixed—it's more useful for comfort than as a primary treatment.

Footwear Modifications

Proper footwear is essential for Achilles tendinitis recovery. Shoes should be supportive, well-cushioned, and fit properly. A slightly elevated heel (heel lift) can reduce strain on the Achilles tendon by shortening the distance it needs to stretch during walking. You can purchase heel lift inserts at pharmacies or have custom orthotics made by a podiatrist for more significant foot issues.

Avoid going barefoot, especially on hard surfaces, during the recovery period. Even around the house, wear supportive slippers or sandals with arch support. High heels should be avoided as they place the calf in a shortened position that can aggravate symptoms when you return to flat shoes. Similarly, completely flat shoes like ballet flats or flip-flops provide inadequate support and should be avoided.

Pain Relief Options

Over-the-counter non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen can help manage pain. However, their use in tendinopathy is somewhat controversial. While they provide symptomatic relief, some research suggests they may slightly impair tendon healing when used long-term. For short-term pain management (1-2 weeks), they're generally considered safe. For longer-term management, acetaminophen may be a better choice as it doesn't affect the healing process.

Topical pain relievers, including NSAID gels and creams, can provide localized relief with less systemic absorption than oral medications. These can be applied directly to the painful area 3-4 times daily. Some people find relief from topical menthol or capsaicin preparations, which work by providing counter-irritation that temporarily masks pain signals.

When Should I See a Doctor for Achilles Tendinitis?

See a healthcare provider if your Achilles pain doesn't improve within 1-2 weeks of self-care, if you have severe pain or sudden onset of symptoms, if you notice significant swelling or cannot bear weight, or if you hear a pop or snap in the heel area. Seek immediate care if you suspect a tendon rupture—signs include sudden severe pain, inability to push up on your toes, and a gap in the tendon.

While most cases of Achilles tendinitis respond well to self-care measures, certain situations warrant professional evaluation. If you've been diligently resting, icing, and modifying activities for 1-2 weeks without improvement, it's time to see a healthcare provider. Persistent pain suggests you may need a more structured treatment program, possibly including physical therapy, or that another condition may be contributing to your symptoms.

Severity of symptoms also guides when to seek care. Mild discomfort that doesn't significantly affect daily activities can often be managed at home initially. However, pain that makes it difficult to walk normally, that wakes you at night, or that's present even at rest indicates a more significant problem requiring evaluation. Similarly, if you notice progressive worsening despite self-care efforts, don't wait—early intervention typically leads to better outcomes.

Certain symptom patterns require prompt medical attention. A sudden onset of severe pain—especially if accompanied by a "pop" or "snap" sensation—may indicate a partial or complete tendon rupture. This is a medical emergency requiring immediate evaluation. Other concerning signs include inability to push up onto your toes, a visible gap or depression in the tendon, and significant bruising that develops after an acute injury.

What to Expect at Your Appointment

When you see a healthcare provider for Achilles tendon problems, they'll start with a thorough history and physical examination. Be prepared to describe when symptoms started, what makes them better or worse, your activity level, and any previous injuries. The physical exam will assess tendon tenderness, swelling, strength, flexibility, and the presence of any thickening or nodules.

Several clinical tests help evaluate Achilles tendon function. The Thompson test (squeezing the calf to see if the foot moves) can identify complete ruptures. Strength testing—including heel raises—assesses tendon integrity and function. Your provider may also examine your walking pattern, foot alignment, and calf flexibility to identify contributing factors.

Imaging studies aren't always necessary but may be recommended in certain situations. Ultrasound is often the first-line imaging choice as it's readily available, cost-effective, and excellent at showing tendon structure, thickness, and any tears. MRI provides more detailed images and may be ordered for complex cases, when surgery is being considered, or when the diagnosis is uncertain.

How Is Achilles Tendinitis Treated?

The primary treatment for Achilles tendinitis is physical therapy, particularly eccentric exercises (slow heel drops) which have 60-90% success rates. Treatment also includes activity modification, proper footwear, and sometimes orthotics. Additional options include extracorporeal shockwave therapy, platelet-rich plasma injections, or night splints. Surgery is reserved for severe cases unresponsive to 6+ months of conservative treatment.

Physical therapy is the cornerstone of Achilles tendinitis treatment, with eccentric exercises being the most evidence-based intervention. The Alfredson protocol—developed by Swedish orthopedic surgeon Håkan Alfredson—involves performing heel drops from a step, slowly lowering the affected heel below step level over 3-5 seconds. This eccentric loading has been shown to stimulate tendon healing and remodeling, with studies demonstrating 60-90% success rates when performed consistently.

The eccentric exercise program typically involves 3 sets of 15 repetitions, performed twice daily for 12 weeks. Some discomfort during the exercises is acceptable and even expected, but sharp or worsening pain indicates you may need to reduce intensity. The exercises are performed both with a straight knee (to target the gastrocnemius muscle) and with a bent knee (to target the soleus muscle). A physical therapist can ensure you're performing the exercises correctly and progress the program appropriately.

Beyond eccentric exercises, a comprehensive physical therapy program addresses contributing factors. This includes calf stretching to improve flexibility, strengthening exercises for the entire lower extremity, and balance training to improve proprioception. Your therapist may also use manual therapy techniques, instrument-assisted soft tissue mobilization, or dry needling to address muscle tightness and promote healing.

Additional Treatment Options

Extracorporeal shockwave therapy (ESWT) is a non-invasive treatment that delivers acoustic waves to the affected tendon. These shockwaves are thought to stimulate healing by increasing blood flow and triggering cellular repair processes. Research shows moderate effectiveness, particularly for chronic cases that haven't responded to other conservative measures. Treatment typically involves 3-5 sessions spaced 1-2 weeks apart.

Platelet-rich plasma (PRP) injections involve injecting concentrated platelets from your own blood into the damaged tendon. The theory is that growth factors in platelets promote tissue healing. While PRP has gained popularity, research results have been mixed—some studies show benefit while others show no advantage over placebo. It remains an option for cases not responding to physical therapy, though it's often not covered by insurance.

Night splints hold the ankle in a neutral or slightly stretched position during sleep, preventing the tendon from contracting overnight. This can reduce morning stiffness and pain. Some people find them helpful, particularly those with significant morning symptoms, though evidence for their effectiveness is limited.

Surgery for Achilles Tendinitis

Surgery is rarely needed for Achilles tendinitis and is considered only after 6 or more months of failed conservative treatment. Surgical options include debridement (removing damaged tissue), tendon repair, or gastrocnemius release (lengthening the calf muscle). The specific procedure depends on the location and extent of damage identified on imaging.

Following surgery, recovery requires a structured rehabilitation program lasting 4-6 months. Initial immobilization in a boot or cast is followed by gradual weight-bearing and physical therapy. Return to full activity—including sports—may take 6-12 months. While surgery can be very effective, the prolonged recovery time underscores why it's reserved for cases unresponsive to conservative treatment.

How Can I Prevent Achilles Tendinitis?

Prevent Achilles tendinitis by increasing activity gradually (no more than 10% per week), warming up properly before exercise, maintaining calf flexibility through regular stretching, wearing appropriate footwear, cross-training to avoid repetitive stress, and maintaining a healthy weight. If you've had previous tendinitis, continue maintenance exercises indefinitely.

The most effective prevention strategy is gradual progression of activity. Whether you're starting a new exercise program or returning after time off, increase intensity, duration, and frequency slowly. The commonly cited "10% rule"—increasing weekly mileage or training load by no more than 10% per week—provides a useful guideline, though some individuals may need even more gradual progression depending on their baseline fitness and history.

Proper warm-up before exercise prepares your muscles and tendons for activity. A good warm-up increases blood flow, raises tissue temperature, and improves tendon elasticity—all of which reduce injury risk. Start with 5-10 minutes of light cardiovascular activity (easy jogging or cycling) followed by dynamic stretches that move your joints through their full range of motion. Save static stretching for after your workout when tissues are warm.

Regular calf stretching maintains the flexibility needed for healthy Achilles tendon function. Tight calf muscles increase tendon strain during activity. Perform both straight-leg (targeting gastrocnemius) and bent-knee (targeting soleus) calf stretches. Hold each stretch for 30 seconds and repeat 2-3 times. Stretch daily, especially after exercise when muscles are warm and most receptive to lengthening.

Footwear and Training Considerations

Appropriate footwear is essential for tendon health. Running shoes should be replaced every 300-500 miles, as cushioning materials break down with use even if the shoes still look fine. Choose shoes appropriate for your foot type and activity—a specialty running store can help with gait analysis and recommendations. If you have significant foot alignment issues, custom orthotics from a podiatrist may be beneficial.

Cross-training reduces repetitive stress on the Achilles tendon by distributing load across different movement patterns. If you're a runner, incorporate cycling, swimming, or strength training into your routine. These activities maintain fitness while giving the Achilles tendon relative rest. Cross-training also addresses muscle imbalances that can develop from single-sport training.

Strength training for the lower extremity helps prevent tendon problems by improving the muscle's ability to absorb force. Include exercises for the calves (heel raises), quadriceps, hamstrings, and hip muscles. Strong muscles reduce the load that tendons must handle. For those with previous tendinitis, maintenance eccentric exercises (even after symptoms resolve) can help prevent recurrence.

What Is the Recovery Timeline for Achilles Tendinitis?

Mild Achilles tendinitis typically improves within 1-2 weeks with rest and self-care. Moderate cases may take 4-6 weeks with physical therapy. More severe or chronic cases can require 3-6 months of dedicated treatment. Complete recovery—including return to full activity—may take up to 12 months for long-standing cases. Consistency with treatment is the most important factor influencing recovery time.

Recovery from Achilles tendinitis follows a general pattern, though individual experiences vary based on severity, treatment adherence, and other factors. Mild cases caught early often respond quickly—within 1-2 weeks—to simple measures like rest, ice, and activity modification. These are typically cases where pain is present only after activity and doesn't limit daily function.

Moderate cases with more consistent pain and some functional limitation usually require 4-6 weeks of treatment, including physical therapy with eccentric exercises. During this phase, you'll likely be able to perform daily activities normally but may need to continue avoiding high-impact sports. Progress can feel slow, but consistency with your exercise program is crucial—tendon remodeling takes time.

Severe or chronic cases—particularly those present for months before treatment begins—may require 3-6 months of dedicated rehabilitation. The tendon has undergone more significant degenerative changes that take longer to address. However, even these cases have good outcomes with persistent treatment. Studies show that 60-90% of patients improve with non-surgical management, regardless of initial severity.

Returning to Activity

Return to activity should be gradual and guided by symptoms. A useful guideline is that pain should not exceed 3-4 out of 10 during activity and should return to baseline within 24 hours. If pain increases progressively over multiple sessions, you're progressing too quickly. Most people can return to light jogging 6-8 weeks after starting treatment, with gradual progression back to full training over the following 4-8 weeks.

For athletes and active individuals, returning to pre-injury activity levels is generally achievable, though patience is required. Research suggests that most runners are able to return to their previous mileage within 6-12 months. However, rushing this process significantly increases recurrence risk. Your physical therapist can help design a gradual return-to-sport program based on your specific goals and progress.