Last updated: March 2026 | 9 min read
What Is Achilles Tendinopathy?
A stiff, achy Achilles tendon when you take your first steps in the morning. Pain at the back of your heel that warms up after 10 minutes of running — then comes back worse the next day.
That’s Achilles tendinopathy — the most common tendon injury in runners. Unlike a tendon rupture (which is sudden and dramatic), tendinopathy develops gradually from repetitive overload.
It’s also one of the most mismanaged injuries. Stretching and rest alone will not fix it. Here’s what actually works.
Why Your Achilles Is Breaking Down
Your Achilles tendon connects your calf muscles to your heel bone. It absorbs forces up to 8 times your body weight when running. When load exceeds the tendon’s capacity to recover, degeneration begins.
Main causes:
- Sudden mileage spike — adding speed work or hills too quickly
- Weak calf muscles — the tendon compensates for what the muscle can’t handle
- Transitioning to minimalist shoes too fast — increases load on the tendon dramatically
- Running on hard surfaces — less shock absorption
- Poor ankle mobility — alters foot strike mechanics
Critical note: Stretching an Achilles tendinopathy makes it worse. The tendon needs load, not lengthening.
The 5-Phase Recovery Protocol
Phase 1 — Reduce Load (Days 1-5)
- Reduce running by 50-70%
- No speed work, no hills, no barefoot running
- Ice after activity only (not before)
- Heel raises in your shoes to temporarily reduce tendon load
- Do not stretch the calf or Achilles
Goal: Morning stiffness below 4/10 before Phase 2.
Phase 2 — Isometric Loading (Week 1-2)
Isometric exercises reduce tendon pain immediately and start the healing process.
Exercise 1: Isometric Calf Hold
- Stand on both feet, rise up onto tiptoes
- Hold the top position for 45 seconds
- 5 reps, twice per day
- Some discomfort is normal — stop if pain exceeds 4/10
Goal: Complete 5 × 45 second holds with pain below 3/10.
Phase 3 — Eccentric and Heavy Slow Resistance (Week 2-5)
This is the most evidence-based phase for Achilles tendinopathy. Heavy slow resistance training remodels the tendon tissue.
Exercise 2: Eccentric Heel Drops (Alfredson Protocol)
- Stand on the edge of a step, both feet
- Rise up on both feet
- Transfer to affected foot only
- Lower your heel below step level over 3-4 seconds
- 3 sets × 15 reps, twice per day
- Do both straight knee AND bent knee versions
Exercise 3: Single-leg Calf Raise (slow)
- Stand on affected foot only, flat surface
- Rise up over 3 seconds, lower over 3 seconds
- Add weight in a backpack when bodyweight becomes easy
- 3 sets × 12 reps each side
Goal: 3 sets × 12 single-leg calf raises with added load, pain below 3/10.
Phase 4 — Return to Running (Week 5-8)
| Week | Session | Key rule |
|---|---|---|
| Week 5 | 2 min run / 2 min walk × 8 | Flat surface, no hills |
| Week 6 | 5 min run / 1 min walk × 6 | Monitor next-morning pain |
| Week 7 | 12 min run / 1 min walk × 3 | No speed work yet |
| Week 8 | 25-30 min continuous | If pain stays below 3/10 |
Key rule: check your Achilles the morning after each session. If pain increases, drop back one week.
Phase 5 — Prevent Recurrence (Ongoing)
- Single-leg calf raises 3x per week — forever
- Increase mileage maximum 10% per week
- No sudden return to speed work or hills after a break
- Replace shoes every 700km
The #1 Mistake With Achilles Tendinopathy
Stretching the tendon aggressively.
When a tendon is degenerating, it needs compressive load to remodel — not tension. Aggressive calf stretching compresses the tendon insertion and worsens the condition, especially in insertional Achilles tendinopathy (pain right at the heel bone).
Replace stretching with strengthening.
Insertional vs Mid-portion: Know Your Type
| Mid-portion | Insertional | |
|---|---|---|
| Location | 2-6cm above heel | At the heel bone |
| Eccentric drops | ✅ Highly effective | ⚠️ Avoid below neutral |
| Heel raise | Not needed | Helpful short-term |
If your pain is right at the heel bone, do eccentric drops only down to neutral (not below the step level).
When to See a Physio in Person
- Sudden sharp pain during a run — rule out partial rupture
- Significant swelling or a visible lump on the tendon
- No improvement after 8 weeks of this protocol
- Pain at rest or during normal walking
Recovery Timeline Summary
| Phase | Duration | Goal |
|---|---|---|
| 1 — Reduce load | Days 1-5 | Morning stiffness below 4/10 |
| 2 — Isometric | Week 1-2 | Pain-free holds |
| 3 — Strengthen | Week 2-5 | Single-leg calf raise with load |
| 4 — Return | Week 5-8 | Back to running |
| 5 — Maintenance | Ongoing | No recurrence |
The Bottom Line
Achilles tendinopathy requires patience and progressive loading — not rest and stretching. Follow the Alfredson eccentric protocol, monitor your morning pain daily, and most runners are back to full training within 8 weeks.
Written by the HealToRun team — physio students and running enthusiasts dedicated to keeping you on the road.
Dealing with multiple running injuries?
Our Running Injury Recovery Guide covers Achilles tendinopathy, runner’s knee, IT band syndrome, plantar fasciitis and shin splints — all in one 24-page physio-approved guide.