Achilles Tendinopathy in Runners: Prevention and Treatment

The Achilles tendon is the strongest in the human body. With every stride, it absorbs forces equivalent to six to eight times your body weight. When you ask too much of it, too soon, Achilles tendinopathy can set in—and trust me, it's one of the most frustrating injuries for runners. It's not just inflammation; the tendon undergoes deep structural changes, and patience is key for recovery.

Two Forms, Two Locations

Mid-Portion Achilles Tendinopathy

This is the most common form among runners. You'll experience pain 2 to 6 cm (roughly 1 to 2.5 inches) above the heel, often accompanied by a noticeable bump or thickening of the tendon. The typical pattern is pain at the beginning of your run, which lessens as you warm up, only to return afterward. Morning stiffness when you get out of bed is also a classic sign.

Insertional Achilles Tendinopathy

Here, the pain is right where the tendon attaches to your heel bone. Shoes with a stiff heel counter often exacerbate the issue. Management for this type differs slightly from mid-portion tendinopathy; full dorsiflexion exercises are generally poorly tolerated.

The Central Role of Load

Contrary to popular belief, Achilles tendinopathy isn't a classic inflammatory condition (though it's still sometimes called “tendinitis”). Based on my research, especially Jill Cook's work, it's primarily a problem with the tendon's adaptation to load. The tendon progresses through a continuum: reactive → degenerative changes → degenerative tendinopathy. The good news is that the first two stages are reversible if you manage your load effectively.

Common mistakes that trigger it:

• Increasing volume too quickly — going from 30 to 50 km (approx. 18 to 31 miles) per week in two weeks is a typical scenario.
• Adding in interval training or hills without allowing your tendon time to adapt.
• Changing shoes, especially if you suddenly reduce the drop, which puts extra stress on your Achilles tendon.
• Returning to running after a break, which is when your tendon is most vulnerable.
• Personal factors: age (risk increases after 35-40), certain medications (fluoroquinolones, statins), diabetes.

The Eccentric Protocol: Treatment Cornerstone

Alfredson's protocol (1998) remains THE gold standard for mid-portion Achilles tendinopathy. The principle involves performing heel drops on the edge of a step (eccentric calf muscle contraction), twice a day, 3 sets of 15 repetitions, for twelve weeks. Be aware that it's designed to be a little painful during the exercise—it's counter-intuitive, but that's part of the protocol.

What the Science Says

Overall, it works: studies report a 60-90% satisfaction rate. However, there are nuances:

• It works better for mid-portion tendinopathy than for insertional tendinopathy.
• Twelve weeks is a minimum—personally, I've read that some runners take three to six months before experiencing significant improvement.
• Protocols combining eccentric and concentric exercises (heavy slow resistance) yield comparable results, and people often find them more engaging.
• Isometric exercises (static contractions) can help in the acute phase to calm pain before progressing to dynamic exercises.

The Question of Drop

Shoe drop—the height difference between the heel and forefoot—directly impacts your Achilles tendon. A low drop (0-4 mm) places more stress on the tendon. A high drop (10-12 mm) can relieve it but may shift forces to the knee.

There's no single ideal drop for everyone. If you're experiencing Achilles tendon pain, temporarily increasing your shoe drop might provide relief. However, this doesn't address the root cause. Calf muscle strengthening remains essential alongside it.

Progression: The Watchword for Returning to Running

Returning to running after Achilles tendinopathy isn't something to rush. Here's a general framework—to be adapted with your physical therapist or sports doctor:

1. Phase 1 — Pain Management (Weeks 1-2): Reduce load, perform isometric exercises, potentially active walking. No complete rest unless the pain is truly severe.
2. Phase 2 — Strengthening (Weeks 3-8): Eccentric protocol or heavy slow resistance. Maintain cross-training activities (cycling, swimming).
3. Phase 3 — Return to Running (Weeks 6-12): Walk-run intervals, flat terrain only, increase volume by a maximum of 10-15% per week.
4. Phase 4 — Full Return (Weeks 12+): Gradually reintroduce speed work, hills, then your usual mileage.

A little tip: morning pain is your best indicator. If it increases the day after a session, you've likely overdone it.

Prevention: Better to Be Proactive

Prevention involves simple principles, but they require consistency:

• Increase volume and intensity gradually; avoid sudden spikes.
• Perform 2-3 calf strengthening sessions per week (heel raises, single-leg squats).
• Avoid abrupt changes in shoes or running surfaces.
• Be extra vigilant when returning to activity after a break.
• If you experience Achilles tendon pain in the morning when getting out of bed, don't ignore it—it's often the first warning sign.