Achilles tendonitis vs. plantar fasciitis – How to tell the difference

We are often consulted by patients who have been misdiagnosed with plantar fasciitis when it is obvious that they actually have Achilles tendonitis or tendinopathy. I find it bizarre that doctors and physios get these diagnoses mixed up, because it’s very easy to distinguish between them.

In this article, I’ll point out the main differences between Achilles tendonitis and plantar fasciitis, how to treat them, and what to do if you have both. Remember, if you need more help with an Achilles injury, you're welcome to consult one of our team via video call.

The terms tendinitis, tendonitis, tendinosis, and tendinopathy mean the same thing for all practical purposes, and we use these interchangeably in our articles.

In this article:

1. Achilles tendonitis vs. plantar fasciitis

2. What treatment works best

3. What to do if you have both

4. How we can help

We've also made a video about this:

Achilles tendonitis vs. plantar fasciitis

Similarities between Achilles tendonitis and plantar fasciitis

Achilles tendonitis and plantar fasciitis share some symptoms. For example:

• It usually feels very painful and/or stiff when you try to walk first thing in the morning or after sitting still for long.

• The discomfort usually improves when you move around but gets worse again if you spend too much time on your feet.

Differences between Achilles tendonitis and plantar fasciitis

The main difference between the conditions lies in where you feel the pain and stiffness.

With Achilles tendonitis, you feel the symptoms in the Achilles tendon, either where it attaches to the back of the heel bone (insertional Achilles tendonitis) or higher up in the tendon, at the back of your lower leg (mid-portion).

With plantar fasciitis, you experience the pain underneath the foot, where the plantar fascia attaches to the front of heel bone.

It is possible to have both conditions. But pain in your Achilles tendon will not be plantar fasciitis. And pain under your foot, in the area of your arch, will not be Achilles tendonitis.

What treatment works best

Both of these conditions are overuse injuries. This means that your injury was caused by doing too much of an activity without allowing enough recovery time.

Once injured, your plantar fascia or Achilles tendon (depending on which is affected), loses some of its strength and is no longer able to tolerate all the loads of your normal daily activities. This is why even things like walking or standing may be painful.

The main treatment for both plantar fasciitis and Achilles tendonitis is therefore a combination of:

1. Relative rest - where you reduce or limit the painful activities to a level that does not cause your symptoms to feel worse. This is to allow your injury to settle down and start healing.

2. Strength training - to rid yourself of these types of injury for good, you have to restore the strength that you lost due to the injury. The only way to do this is through a graded strength training plan, where you start with low-load, easy exercises and gradually increase the intensity to a level that eventually represent the activities you want to get back to (e.g. walking or running). Interestingly, calf raise exercises (where you go up and down on your toes) are useful for both these conditions.

Heel raise exercises strengthen both the Achilles tendon and plantar fascia.

Although the broad treatment approach for these conditions is the same, there are some extra things that can help for plantar fasciitis that won’t help for Achilles tendonitis and vice versa. You can find more specific treatment advice for plantar fasciitis here and for Achilles tendonitis here.

What to do if you have both

It is possible to have both Achilles tendonitis and plantar fasciitis at the same time. You will then have to adapt your rehab according to which of the two conditions is the most flared up and sensitive.

For instance, stretches form an important part of the treatment for plantar fasciitis, but stretching an injured Achilles tendon can often make it feel much worse. So you may have to exclude stretches from your treatment regime until your Achilles tendon can tolerate them.

The same goes for what strength training exercises you do. As mentioned before, calf raise exercises are useful for both these conditions. When you choose the type of calf raise (seated vs. standing on the floor vs. over the side of a step) or intensity (double leg vs. single leg vs. with weights), you have to let the most sensitive of the two injuries guide your choice.

How we can help

Need more help with your Achilles injury? You’re welcome to consult one of the team at TMA online via video call for an assessment of your injury and a tailored treatment plan.

We're all UK Chartered Physiotherapists with Master’s Degrees related to Sports & Exercise Medicine. But at Treat My Achilles we don't just value qualifications; all of us also have a wealth of experience working with athletes across a broad variety of sports, ranging from recreationally active people to professional athletes. You can meet the team here.

About the Author

Maryke Louw is a chartered physiotherapist with more than 15 years' experience and a Master's Degree in Sports Injury Management. Follow her on LinkedIn and ResearchGate.

References:

1. Hutchison, A. M., Evans, R., Bodger, O., Pallister, I., Topliss, C., Williams, P., & Beard, D. (2013). "What is the best clinical test for Achilles tendinopathy?" Foot and Ankle Surgery, 19(2), 112-117.

2. Morrissey, D., et al. (2021). “Management of plantar heel pain: a best practice guide informed by a systematic review, expert clinical reasoning and patient values.” British Journal of Sports Medicine 2021; 55: 1106-1118.

3. Rathleff, Michael Skovdal, et al. "High‐load strength training improves outcome in patients with plantar fasciitis: A randomized controlled trial with 12‐month follow‐up." Scandinavian Journal of Medicine & Science in Sports 25.3 (2015): e292-e300

4. Rhim, H.C., Kwon, J., Park, J., Borg-Stein, J. and Tenforde, A.S., 2021. "A Systematic Review of Systematic Reviews on the Epidemiology, Evaluation, and Treatment of Plantar Fasciitis." Life, 11(12), p.1287.

5. Stecco C, Corradin M, Macchi V, et al. "Plantar fascia anatomy and its relationship with Achilles tendon and paratenon." J Anat. 2013;223(6):665-676. doi:10.1111/joa.12111

6. Tu, P. (2018). “Heel pain: diagnosis and management.” American Family Physician 97.

7. Van Der Vlist, A. C., et al. (2021). "Which treatment is most effective for patients with Achilles tendinopathy? A living systematic review with network meta-analysis of 29 randomised controlled trials." British Journal of Sports Medicine 55(5): 249-256.