A Common Injury With a Specific Treatment Path
The Achilles tendon — the largest and strongest tendon in the body — connects the calf muscles to the heel. It absorbs enormous forces with every step, jump, and push-off. Over time, particularly in active adults over 40, the tendon can develop a degenerative condition called Achilles tendinopathy.
Despite the older term "tendinitis," modern research shows this is rarely an inflammatory condition. It is a degenerative process — the tendon shows disorganized collagen, abnormal blood vessel growth, and structural changes rather than inflammatory cells. This shift in understanding has changed how we treat it.
In St. Petersburg, we see Achilles tendinopathy frequently in walkers using the Pinellas Trail, runners, pickleball players, and tennis players. At Zimmer Medical Group, we manage most cases successfully without specialist referral.
Two Types of Achilles Tendinopathy
The location matters because treatment differs slightly:
Mid-Portion Achilles Tendinopathy
- Pain 2–6 cm above where the tendon attaches to the heel
- Tendon often visibly thickened
- More common in runners and active middle-aged adults
- Usually responds well to standard eccentric exercise programs
Insertional Achilles Tendinopathy
- Pain at the back of the heel where the tendon attaches
- Often associated with bony enlargement (Haglund's deformity)
- More common in older adults and walkers
- Modified eccentric exercises (without going below the level of the floor) work better here
Recognizing the Pattern
Typical symptoms include:
- Gradual onset of posterior heel or lower calf pain
- Stiffness and pain with the first steps in the morning
- Pain that improves with mild activity but worsens with prolonged or vigorous activity
- Visible thickening of the tendon
- Tenderness to direct pressure on the tendon
- Pain with rising up onto the toes
A key feature: pain that "warms up" with activity is typical of tendinopathy. Pain that gets steadily worse during activity, or sharp pain that occurs suddenly, suggests other diagnoses.
When to Worry About Rupture
Acute Achilles rupture is a different problem requiring urgent evaluation. Suspect rupture when:
- A sudden "pop" or sensation of being kicked in the back of the leg
- Sudden inability to push off or rise on toes
- Sharp, severe posterior calf or heel pain
- Visible gap in the tendon when palpated
- Positive Thompson test (squeezing the calf does not produce normal foot plantarflexion)
Achilles rupture is more common in middle-aged "weekend warriors," patients on fluoroquinolone antibiotics, and patients on chronic steroids. It requires prompt evaluation and often surgical or specific non-operative protocols. Don't wait — seek same-day evaluation.
Diagnosis
The diagnosis is usually clinical. Imaging may be helpful when:
- The diagnosis is uncertain
- Symptoms have not improved with appropriate treatment
- Rupture is suspected
- Considering more invasive treatment
Ultrasound is the first-line imaging modality — affordable, dynamic, and excellent for visualizing the tendon. MRI is reserved for complex cases.
What Actually Works: The Treatment Stack
1. Eccentric Loading Exercises (The Cornerstone)
Eccentric calf raises remain the most evidence-supported treatment. The Alfredson protocol, the most studied program, involves:
- 3 sets of 15 repetitions, twice daily
- Both straight-knee (gastrocnemius) and bent-knee (soleus) versions
- Performed on a step (mid-portion tendinopathy) — rise up using both legs, then slowly lower the affected leg below the step
- For insertional tendinopathy, perform on flat ground without going below floor level
- Continue for at least 12 weeks
The exercises will be uncomfortable. Mild to moderate pain during the exercises is acceptable and even expected — provided pain returns to baseline within 24 hours. This loading stimulates tendon remodeling.
2. Heavy Slow Resistance Training
A newer alternative to traditional eccentric protocols: slower, heavier loading with both eccentric and concentric phases. Equally effective, often better tolerated, and requires fewer sessions per week.
3. Activity Modification
Reduce — don't eliminate — provocative activities. Substitute lower-impact activities (cycling, swimming, elliptical) while maintaining fitness.
4. Footwear and Heel Lifts
A small heel lift (1/4 to 1/2 inch) reduces tension on the tendon during recovery. Supportive footwear with adequate cushioning is helpful. Going barefoot on hard floors — common in Florida homes — is often a hidden contributor.
5. Address Contributors
- Tight calf muscles — daily stretching after the acute phase
- Sudden increases in training volume — progress more gradually
- Worn-out shoes — replace running shoes every 300–500 miles
What to Avoid
- Corticosteroid injections directly into the tendon — significant rupture risk; generally avoided
- Complete rest — the tendon needs loading to heal; prolonged rest worsens outcomes
- Returning to high-impact activity too quickly — recurrence is common when patients feel better but the tendon has not fully remodeled
Newer Options for Stubborn Cases
For patients failing 6+ months of eccentric exercise:
- Extracorporeal shock wave therapy (ESWT) — reasonable evidence for both insertional and mid-portion tendinopathy
- PRP injections — mixed but generally favorable evidence; not always covered by insurance
- High-volume image-guided injection — saline injection to disrupt abnormal blood vessels around the tendon
- Surgical debridement or repair — reserved for true treatment failures
Fluoroquinolone Antibiotic Warning
Fluoroquinolones (ciprofloxacin, levofloxacin, moxifloxacin) carry a real risk of Achilles tendinopathy and rupture, particularly in older adults and those on steroids. The FDA carries a boxed warning. If you must take these antibiotics, watch closely for any new tendon pain and stop activity immediately if it occurs.
Setting Realistic Expectations
Achilles tendinopathy responds to treatment, but slowly. A reasonable timeline:
- 4–6 weeks: notable improvement in morning stiffness
- 8–12 weeks: substantial pain reduction with daily activities
- 3–6 months: ability to return to most activities
- 6–12 months: full resolution in most cases
Patients who quit the exercises after a few weeks because they "aren't working fast enough" usually have to start over later.
When to See Your Doctor
- Acute, severe pain with a pop or popping sensation (rupture concern — urgent)
- Pain that has not improved with several weeks of conservative care
- Pain limiting walking or daily activities
- Numbness, weakness, or swelling beyond the tendon area
- Fluoroquinolone antibiotic use with new tendon pain
The American Academy of Orthopaedic Surgeons provides additional patient information on Achilles tendon problems.
Persistent heel cord pain limiting your activity? Contact Zimmer Medical Group for an exam, a structured eccentric exercise program, and the right escalation plan if conservative care isn't enough.
