Can You Keep Running With Achilles Tendinopathy?

What the Evidence Shows

In a randomised controlled trial of 38 people with Achilles tendinopathy, one group continued running and jumping during rehabilitation, guided by a pain-monitoring model, while the other group initially rested from those activities. Both groups followed a tendon-loading strengthening programme. Continuing activity did not produce worse outcomes than active rest.

This is a small study, and it should not be turned into a universal rule about exactly how much pain is acceptable. What it does support is the principle that carefully monitored activity can continue alongside rehabilitation, rather than being abandoned entirely.

Monitoring Your Response, Not a Fixed Pain Number

Pain during running or exercise does not automatically mean that you are damaging the tendon. Some discomfort can be acceptable during rehabilitation, provided the overall response remains manageable.

Rather than relying on a fixed pain threshold, monitor how symptoms respond:

• during the run: is the pain settling, staying steady, or building as you go?
• later that day: has the tendon settled towards its usual baseline?
• the next morning: is morning stiffness or pain clearly worse than usual?

Also pay attention to whether pain starts earlier during the run, becomes progressively more intense, or changes the way you run. Pain intensity is not the only useful marker: mild pain that steadily builds through a run and alters your running can be more telling than a higher score that settles quickly.

A clear and sustained increase in pain or morning stiffness may indicate that the recent training load needs adjusting. One slightly grumpy morning is less informative than a pattern over several days.

Ways to Modify Running

Modifying running doesn't always mean simply doing less. It means identifying which part of the current running load is aggravating symptoms and adjusting the dose accordingly. That might involve:

• Distance: shorter runs, or splitting one longer run into two
• Frequency: more rest days between runs while strength work builds
• Speed: temporarily reducing sprinting, intervals or faster running if these clearly aggravate symptoms; faster running generally increases Achilles loading compared with slower running
• Terrain: temporarily reducing hills may be useful when they clearly aggravate symptoms; for insertional tendinopathy, uphill running can increase ankle dorsiflexion and may be provocative for some runners
• Run-walk: alternating short running and walking intervals can provide a useful way to reintroduce running when continuous running is not yet well tolerated

Running places substantial mechanical demands on the Achilles tendon. A systematic review estimated Achilles tendon loads of approximately 4.15–7.71 times body weight during running, although these are mechanical estimates from healthy populations rather than direct loads in individual patients. It is one reason calf strength and endurance need rebuilding alongside, not after, a return to running.

Building Back Up

As symptoms settle and strength improves, running is progressively reintroduced. Before returning to full training, rehabilitation needs to progress beyond slow calf strengthening towards faster, energy-storage activities such as skipping and hopping, which better prepare the tendon and calf complex for the faster stretch-shortening demands of running.

The exact progression depends on the demands of the runner's normal training. Someone returning to easy 5 km runs has different requirements from someone returning to marathon training, hill running or sprinting.

Being able to run without a large increase in symptoms doesn't necessarily mean the tendon is fully rehabilitated. Running tolerance and tendon capacity are related but not identical. Strength, endurance and energy-storage capacity still need to progress towards the demands of your normal training.

For how training load is best progressed, read Is the 10% Rule for Running Real?.

When to Stop and Get Assessed

After an acute injury, stop running and seek prompt medical assessment if you feel a sudden "pop" or snapping sensation, lose push-off strength, have difficulty walking normally, or develop significant swelling or bruising.

For an ongoing tendinopathy, arrange an assessment if symptoms are steadily worsening despite modifying your running or if the diagnosis is uncertain.

How We Help Runners at IP Physio

We work out how much running your tendon can currently tolerate, how to modify it, and what strength and capacity gaps need closing. Objective calf strength and capacity testing gives us a benchmark for progression and can help identify meaningful limitations or side-to-side differences. Depending on your goals, assessment may include calf strength, repeated single-leg loading and faster stretch-shortening tasks, not simply whether you can perform a pain-free calf raise. We then adjust your running and loading plan based on how your tendon responds from week to week.

For the full picture, including the difference between midportion and insertional tendinopathy, read Achilles Tendinopathy: Midportion vs Insertional, Symptoms & Rehab.