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Expert Advice On What Runners Should Do About Achilles Tendon Pain

Close-up of runner’s achilles tendon
(Image credit: Shutterstock)

Whether you’re training for a marathon or besieging the city of Troy, achilles injuries can be a real nightmare. Unfortunately for runners, an achilles tendon injury is frustratingly common. And unfortunately for Greek armies, once word gets out your seemingly invincible hero has one vulnerability, it only makes sense for Trojans to train their bows on his heel.

Achille tendon problems are familiar to many runners, but they’re also among the most misunderstood injuries – and that begins with how they’re referred to. “Achilles tendonitis” and “achilles tendinitis” are the most searched-for terms on the internet but according to Seth O’Neill, associate professor of physiotherapy at the University of Leicester with a PhD in the subject, it’s not a phrase practitioners use. 

“We actually don't use the term medically now – we call it tendinopathy,” says O’Neill. “ Tendinopathy is just an umbrella term that means you have a problem with the tendon.

“We use that term as opposed to tendonitis because the research shows that it’s not a typical inflammation [anything ending ‘-itis’ technically means ‘inflammation’], like when you twist your ankle, so it doesn’t tend to get better with rest and other anti-inflammatory treatments.

“A sore tendon is what most people understand as achilles tendonitis – it’s just not an inflammatory condition underlying it. It will get swollen and hot, and it hurts. To most people that looks like inflammation but when you test the chemicals and cells in there it’s not typical inflammation.

“We shouldn’t term it inflammation because it affects how people rehab it. They rest, ice it and take anti-inflammatories, and then wonder why it’s not got better when they return to running.”

You can understand the confusion. With most running injuries, like plantar fasciitis and shin splints, rest is the key to treating them. However, that can actually make an achilles tendon problem worse by weakening your calf muscles so that they are unable to handle the load of running when you do start again, leading to a recurrence of the problem. 

As with most running injuries, achilles problems often arise when you suddenly increase either the amount or intensity of your running, which is why they frequently crop up at the start of marathon training. Whether you’re a new runner starting from scratch or an experienced pavement-pounder, it’s always important to build up your training load gradually to ensure your body has the strength to handle it. 

Specific strength training for runners will also help your body cope with the demands of the sport, and with the achilles tendon the key is to strengthen the lower leg with calf raises.

For more information about how to prevent, spot and treat achilles tendinopathy, here’s more from O’Neill.

About Our Expert
About Our Expert
Dr Seth O’Neill

Dr Seth O’Neill is an associate professor of physiotherapy at the University of Leicester with a BSc in physiotherapy and an MSc in musculoskeletal physiotherapy. O’Neill has a particular interest in tendon disorders and his PhD A Biomechanical Approach To Achilles Tendinopathy Management looked at tendinopathy in runners in the UK.

What is the achilles tendon issue runners usually suffer from?

“Predominantly it’s a degenerative process. The true cause of achilles tendinopathy is an imbalance in the wear rate and the repair rate in the tendon – the tissue ends up degrading over a period of time. Eventually it gets to a certain state where the tendon can’t cope and that’s when we get pain.”

What are the symptoms of achilles tendinopathy?

One word stands out when it comes to achilles tendinopathy symptoms – pain.

“Most patients will present with pain either focused on the mid portion of the tendon or the insertion,” says O’Neill. “The insertion is the bit where it attaches into your heel; the mid portion is 2-6cm above that.

“The pain tends to start when they start running. Often it disappears before hurting again afterwards. Or it doesn’t hurt until they’'ve done a run and then it flares up afterwards – it can be sore for hours. Or the pain can come the morning after a run.”

How do you treat it?

Unlike many other running issues, the key with achilles tendinopathy is to stay active while you’re recovering.

“Think of muscles,” says O’Neill. “A tendon is simply part of a muscle – it’s how the muscles attach to bone. If you rest muscles, they waste. The last thing you want to do to a tendon that’s not coping with exercise you’re doing is to totally rest it, because it will degrade even further and waste away.

“Then when you return to running it’s not robust enough to cope, so the symptoms come on even quicker. The key is to take an active approach in your rehabilitation.”

As part of that active rehab you need to strengthen your calf muscles.

“When it comes to the achilles, the capacity of the calf muscles to shock absorb and protect the tendon is key,” says O’Neill.

“Strength training for the calf muscles will make them better co-ordinated and stronger, so they protect the achilles tendon during running.

“For normal endurance running, as opposed to sprinting, most people think it’s about the thigh and bum muscles, but the key is the calf muscles. The calf will generate forces from the soleus – the deep muscle – of eight times your bodyweight and from the gastrocnemius – the superficial muscle – of three times bodyweight. They do the majority of the force propulsion for running.”

So ice and rest are out?

“You can use those things in the very short term if it’s really flared up,” says O’Neill, “but if you can walk without limping then you should look at a little bit of jogging – you just need to drastically reduce the amount you do. And start to do some heel raises to load the calf muscle and make it stronger.”

How do you prevent achilles tendinopathy?

Strong calf muscles and keeping a careful eye on your workload are the two most important factors, but that can be a tricky balance to strike.

“The key is to make sure your calf muscles are nice and strong, but the challenge that you’ve got as a runner is to fit that into your training regime,” says O’Neill.

“If you add strength training to a normal running load you may suffer overload – that degrades the tendon and leads to the problem. You to have to balance the load on the tendon and that includes your exercise at the gym as well as the running.”

Rest days are vital, as is not building up your weekly training workload too quickly.

“One of the big risk factors is not having two days’ rest a week. Having less than that is associated with achilles problems. Having said that, there are runners who train every day. As long as it’s built up to that level gradually, you will cope – the tendon and the muscles will adapt and become more robust.”

O’Neill recommends averaging out your workload from the past four weeks and comparing it with your workload in the current week. There shouldn’t be a big jump from the average to your current workload.

“If your average training load is 12 miles,” says O’Neill, “you should be seeing an increase to 13 or 14 miles that week. If you suddenly upped it to 18 or 20 miles, that can degrade the tissue because it’s not robust enough to cope.”

Are there any exercises and stretches that are especially effective for strengthening your calf muscles?

The calf can be a tricky area to target with strength work, but a variety of calf raises should suffice in hitting both the deep and superficial muscles. Choose your calf raise depending on where the pain is.

“If the pain is in the mid portion – the middle of the tendon – then heel raises over a step are good because they work the full range of the muscle,” says O’Neill.

“If it’s the insertion [where it attaches to your heel], heel raises on a flat surface would be better at first. Add in raises over a step later.”

Other calf exercises to try are bent-knee heel raises, which are surprisingly hard, or seated heel raises where you have a weight on your leg. You can also use a leg press machine with your heels over the end to target your calf muscles. Don’t skimp on the rehab time – it takes time to increase strength in the calf muscles.

“Build up to lift 50% of your bodyweight in the equivalent of a rucksack on your back during calf raises,” says O’Neill. “That's the long-term aim – it will take six to eight weeks to achieve that.”

For more in-depth guidance, Rebecca Christenson, specialist musculoskeletal physiotherapist at Pure Sports Medicine has recommended these achilles tendon exercises.

How much difference can running style or the right shoes make?

In theory heel strikers are less susceptible to getting achilles issues as they put less stress on the area than midfoot or forefoot strikers. However, since your body is generally accustomed to your running style, O’Neill doesn’t recommend changing to combat tendon trouble.

“The trigger for most runners is always an increase in training load,” says O’Neill. “That’s what causes the breakdown in the tendon and the symptoms. The best way to manage in that case is to correct the training load.

“I wouldn’t change people’s running style normally, because it’s hard to do and you can get better benefits from targeting calf strength.”

However, if you do want to change your running style – if you’re attracted to the barefoot running trend for example – you need to make the change gradually.

“If someone has altered their run pattern, like they’ve gone from normal shoes to barefoot, then they would tend to move towards a forefoot strike. If they do it gradually over a period of time, no problem, but if the change is quick then it will increase the load on the tendon and the calf, and that’s what breaks them down.” Use this expert advice on barefoot running to transition safely. 

The potential for tendon issues should also be considered when picking a new pair of trainers. The offset in the sole – how much higher the heel is than the toes – is the key stat, which is why we include that detail in our recommendations for the best running shoes.

“A lot of the new trainers have swapped from being a 10mm heel drop to 6mm or even a flat sole,” says O’Neill.

“A flat shoe increases the amount of movement that the ankle goes through during a step, which means potentially more stress on the achilles. So if you suddenly change your shoe to a level that’s lower, that can increase the strain on the achilles.

“Going for a higher heel, or using a heel insert that lifts the heel, can reduce the stress on the achilles tendon. We sometimes use that for people when the tendon has flared up.”

Nick Harris-Fry is a journalist who has been covering health and fitness since 2015. Nick is an avid runner, covering 70-110km a week, which gives him ample opportunity to test a wide range of running shoes and running gear. He is also the chief tester for fitness trackers and running watches, treadmills and exercise bikes, and workout headphones.