How to Fix Achilles Tendonitis: Evidence-Based Recovery Guide

Achilles tendonitis—that nagging pain at the back of your heel—can sideline runners, walkers, and anyone who relies on their feet. Like other tendinopathies, it requires a specific approach: progressive loading, not just rest.

This guide covers:

1. Understanding Achilles tendinopathy
2. Why rest alone doesn't work
3. The eccentric exercises that heal it
4. How to return to activity safely

Understanding Achilles Tendinopathy

What's Happening

The Achilles tendon connects your calf muscles to your heel bone. When overloaded—through too much activity, sudden increases, or repetitive stress—the tendon develops degenerative changes.

Important: Despite the name "tendinitis" (suggesting inflammation), chronic Achilles pain is usually tendinopathy (degeneration). This distinction matters for treatment.

Types of Achilles Problems

Midportion tendinopathy:

• Pain 2-6 cm above the heel bone
• Most common type
• Swelling or thickening of tendon
• Responds well to eccentric exercises

Insertional tendinopathy:

• Pain right at the heel bone
• Where tendon attaches
• May involve bone spur or bursitis
• Requires modified approach (see below)

Symptoms

• Pain at back of ankle/heel
• Morning stiffness (first steps)
• Pain at start of activity that may ease up
• Thickening or swelling of tendon
• Creaking sensation (crepitus)
• Pain after activity

Risk Factors

• Sudden increase in running/walking
• Tight calves
• Weak calves
• Change in footwear
• Running on hills
• Older age
• Previous Achilles problems
• Certain antibiotics (fluoroquinolones)

Why Rest Doesn't Fix It

The Problem with Rest

Rest feels logical—if it hurts, stop using it. But with tendinopathy:

• Tendons need load to heal
• Rest causes further degeneration
• When you return to activity, the weakened tendon fails again
• The cycle repeats

What Tendons Need

Tendons adapt to load. Progressive loading stimulates tendon repair and remodeling. The key is finding the right load—enough to stimulate healing, not so much that it causes further damage.

The Eccentric Loading Protocol

Eccentric exercise (muscle lengthening under load) is the gold standard treatment for Achilles tendinopathy.

The Alfredson Protocol

This is the original and most studied protocol for midportion Achilles tendinopathy.

Straight-knee eccentric heel drop:

1. Stand on step with balls of feet on edge
2. Rise up on both feet (use good leg to help)
3. Shift weight to affected leg
4. Slowly lower heel below step level (3-4 seconds)
5. Use good leg to rise back up (don't push up with affected leg)
6. 15 reps, 3 sets

Bent-knee eccentric heel drop:

1. Same position
2. Bend affected knee slightly (20-30°)
3. This targets the soleus muscle
4. Same slow lowering
5. 15 reps, 3 sets

Protocol:

• Both exercises, twice daily
• Total: 180 reps per day
• 12 weeks minimum

Pain During Exercise

Some pain during eccentric exercises is expected and acceptable.

Pain guidelines:

• Up to 5/10 pain during exercise: Acceptable
• Pain shouldn't increase during the set
• Pain should return to baseline within 24 hours
• If pain is worse the next day: Reduce load

If exercises are too painful:

• Start on flat ground (no heel drop below level)
• Progress to step when tolerable

If exercises are too easy:

• Add weight (backpack or hold dumbbells)
• Progress load gradually

Insertional Tendinopathy Modification

Insertional Achilles problems require a modified approach. The insertion doesn't tolerate the stretch position of the standard protocol.

Modified protocol:

• Don't drop heel below level of step
• Lower only to neutral (flat) position
• Add load rather than range
• Isometric holds may be helpful first

Isometric Exercise (For Acute Pain)

If pain is severe, start with isometrics before eccentrics.

Isometric Calf Raise Hold

How to do it:

1. Stand on step, balls of feet on edge
2. Rise up to mid-range (not full raise)
3. Hold for 45 seconds
4. 4-5 reps, 2-3 times daily

Why it works: Isometrics can reduce pain while beginning to load the tendon. Research shows they provide immediate pain relief.

Supporting Treatments

Calf Flexibility

Tight calves increase Achilles load. But stretch gently—aggressive stretching can aggravate the tendon.

Gentle calf stretch:

1. Wall stretch with knee straight
2. Gentle stretch, not maximum
3. Hold 30-45 seconds
4. 2-3 times daily

Soleus stretch:

1. Wall stretch with knee bent
2. Hold 30-45 seconds
3. 2-3 times daily

Calf Strengthening

Beyond eccentrics, build overall calf strength.

Seated calf raises:

• Weight on knees
• Raise and lower heels
• 15-20 reps, 3 sets

Standing calf raises (bilateral):

• Both feet, rise onto toes
• Once pain allows
• 15-20 reps, 3 sets

Foam Rolling

Roll calves:

• 90 seconds per leg
• Don't roll directly on the painful tendon

Heel Lifts

A temporary heel lift (0.5-1 inch) reduces stretch on the Achilles. Can be helpful during acute phase.

Load Management

Activity Modification

You don't need complete rest, but modify activities that aggravate the tendon.

Reduce:

• Running volume (or stop temporarily)
• Hill running (especially downhill)
• Speed work
• Jumping

Maintain:

• Walking (if tolerable)
• Cycling (usually well-tolerated)
• Swimming
• Low-impact activity

The 24-Hour Rule

After any activity, assess the tendon 24 hours later:

• Same or better: Activity was appropriate
• Significantly worse: Activity was too much

Use this feedback to guide activity levels.

Return to Running Protocol

Prerequisites:

• No pain with walking
• Single-leg heel raise without pain
• 4-6 weeks of consistent eccentric training

Week 1-2:

• Walk/run intervals
• 1 minute run / 4 minutes walk × 4
• Flat, soft surfaces

Week 3-4:

• 2 minutes run / 3 minutes walk × 4-5
• Continue eccentrics

Week 5-6:

• 3-4 minutes run / 2 minutes walk × 4-5
• Increase gradually

Week 7+:

• Progress to continuous running
• Increase by 10% per week maximum
• Continue eccentric maintenance

Timeline Expectations

Typical recovery:

• Week 1-4: Beginning of improvement, may be variable
• Week 5-8: Noticeable decrease in symptoms
• Week 8-12: Significant improvement
• 3-6 months: Full resolution for most cases

Important: Achilles tendinopathy often takes 3-6 months to fully resolve. Early return to full activity leads to recurrence.

Red Flags

See a doctor immediately if:

• Sudden pop or snap in the tendon
• Sudden severe pain
• Inability to rise on toes at all
• Visible gap in the tendon
• Significant swelling

These may indicate a partial or complete tear requiring different treatment.

Common Mistakes

Mistake 1: Complete Rest

Rest weakens the tendon further. Progressive loading is essential.

Mistake 2: Stopping When Pain Decreases

Tendons need time to fully remodel. Continue exercises for 12 weeks minimum, even after pain resolves.

Mistake 3: Returning to Running Too Soon

Feeling better doesn't mean the tendon is healed. Premature return leads to recurrence.

Mistake 4: Aggressive Stretching

The tendon is already irritated. Aggressive calf stretching can make it worse. Stretch gently.

Mistake 5: Ignoring Contributing Factors

If your training error caused the problem, returning to the same training will cause it again. Address volume, intensity, and footwear.

Footwear Considerations

Running Shoes

• Replace worn shoes (every 300-500 miles)
• Adequate heel cushioning
• Appropriate heel-to-toe drop for your mechanics
• Avoid sudden changes in shoe type

Minimalist/Zero Drop

If you developed Achilles problems after switching to minimalist shoes:

• Transition was likely too fast
• Return to traditional shoes temporarily
• If you want to transition, do it very gradually (months, not weeks)

Daily Footwear

• Avoid flat shoes (flip-flops, ballet flats)
• Some heel height reduces Achilles stress
• Supportive footwear helps

Prevention (After Recovery)

Ongoing Maintenance

2-3x per week:

• Eccentric heel drops: 2 sets of 15
• Calf raises: 2 sets of 15-20
• Calf stretching

Training Principles

• Progress running volume by max 10% per week
• Include easy days
• Don't suddenly add hills or speed
• Listen to early warning signs

Early Warning Signs

Intervene immediately if you notice:

• Morning stiffness returning
• Pain at start of runs
• Tendon feeling "thick"
• Any pain during or after activity

Don't push through these. Increase eccentric work, reduce running volume.

The Bottom Line

Achilles tendinopathy requires progressive loading to heal. The protocol:

1. Eccentric exercises: Alfredson protocol, twice daily, 12 weeks
2. Load management: Reduce aggravating activities, don't rest completely
3. Isometrics first: If pain is severe
4. Modify for insertional: Different approach for heel bone pain
5. Return gradually: Slow progression back to activity
6. Maintain: Continue exercises long-term

Most cases resolve in 3-6 months with consistent eccentric loading. The key is progressive exercise—not rest, not passive treatments—combined with smart load management.

Your Achilles can heal. Load it progressively, be patient with the timeline, and it will rebuild stronger than before.