Achilles Tendon Injuries

01Know the Tendon

The Achilles is the thickest tendon in the body. Its collagen fibres twist as they descend, helping store elastic energy. Issues for runners usually fall into two buckets:

• Mid-portion tendinopathy: Soreness 2–6 cm above the heel bone, often aggravated by volume spikes.
• Insertional tendinopathy: Pain right on the heel where the tendon attaches, aggravated by uphill running and deep dorsiflexion.

Sharp pain after a sudden pop, inability to push off, or visible tendon deformity warrants urgent medical assessment to rule out rupture.

02Common Triggers

• Rapid increases in weekly mileage, hill repeats, or plyometric workouts without adaptation time.
• Switching to minimalist shoes or track spikes that add calf load before the tendon is ready.
• Weak or endurance-poor calf muscles, especially soleus, leading the tendon to absorb excessive strain.
• Poor sleep, low energy availability, or systemic fatigue that reduces tissue recovery capacity.
• Previous Achilles issues—scarred collagen and altered biomechanics raise recurrence risk.

03Early Care & Treatment

Calm symptoms first, then add load back in:

• Relative rest: Trim running volume and avoid hills or sprints for a week or two while pain settles.
• Isometrics: Hold calf raises for 30–45 seconds, 4–5 reps, to reduce pain and maintain strength.
• Footwear tweaks: A small heel lift or higher-drop shoe can temporarily offload the tendon.
• Monitor morning stiffness: It should decrease over several days. If stiffness worsens, pull back further.
• Seek assessment if you have significant swelling, crepitus, or pain that persists beyond two weeks despite modifications.

04Rest or Keep Training?

Complete rest rarely solves a tendon issue. The collagen needs progressive load to reorganise, but it must be the right amount.

• Run if pain stays ≤3/10 during the session, does not worsen as you go, and settles to baseline by the next morning.
• Swap in low-impact cardio—cycling, deep-water running, elliptical—on days when symptoms flare above that threshold.
• Avoid fast accelerations and hills until you can run easy mileage pain-free for 10–14 days.
• Log your response: Track pain and stiffness alongside training to spot patterns before they escalate.

In short, keep training your aerobic engine, but dial intensity and tendon stress up or down based on symptoms.

05Progressive Rehab Plan

After symptoms cool, rebuild tendon capacity systematically:

1. Heavy slow resistance: 3–4 sets of 6–8 slow calf raises (knee straight and bent) every other day to strengthen both gastrocnemius and soleus.
2. Plyometric prep: Add double-leg hops, progressing to single-leg pogo jumps when pain-free.
3. Return-to-run structure: Start with short run-walk intervals or strides on flat ground, increasing only one variable—duration, frequency, or intensity—each week.
4. Maintain strength work: Keep at least two calf sessions per week even after you return to full mileage.

If progress stalls for 6–8 weeks, consider consulting a sports medicine professional for imaging, adjunct therapies, or gait review.

06Why It Comes Back

Achilles issues often recur because runners resume peak training before the tendon has rebuilt capacity.

• Incomplete loading: Stopping rehab exercises once pain fades means the tendon never regains full strength.
• Training spikes: Jumping into speedwork, hills, or racing too soon re-introduces high strain.
• Underlying imbalances: Calf weakness, stiff ankles, or hip control deficits can keep stress localised at the tendon.
• Poor recovery habits: Limited sleep and fuel impair tendon remodeling and collagen synthesis.

Build resilience by periodising training, scheduling deload weeks, and keeping calf strength work as a year-round habit. Regularly check in on morning stiffness; it is an early warning signal that you are overdoing it.

If symptoms persist or worsen, consult a medical professional.