Achilles Tendonitis vs. Plantar Fasciitis – Which Do I Have?

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Two of the most common types of foot pain, Achilles tendonitis and plantar fasciitis, can make getting out of bed or going for a walk borderline excruciating.

Understanding the differences between these two conditions isn’t always immediately obvious…

Achilles tendonitis refers to inflammation of the Achilles tendon (behind the ankle/lower calf), whereas plantar fasciitis is an inflammation of the connective tissue at the bottom of your foot.

In this article we’ll explore the differences and similarities of both, and how to decipher between them so that you can target the right structures.

Let’s get to it!

Difference Between Plantar Fasciitis & Achilles Tendonitis

Differences & Similarities Between Achilles Tendonitis & Plantar Fasciitis

The main things to look for when deciphering between Achilles tendonitis and plantar fasciitis is where the location of the pain is, what kind of pain it is, what the aggravating factors are, and how the pain reacts to activity and rest

Differences

It’s important to note that even though both the Achilles tendon and the plantar fascia connect at the heel, there are potential differences in some key areas:

  • Location — Achilles tendonitis usually causes pain either at the heel or along the lower calf, whereas plantar fasciitis usually causes pain at the bottom of the foot along the inside arch.
  • Cause of Pain — Achilles tendonitis most commonly happens due to a strain on the tendon, whereas plantar fasciitis usually happens due to an accumulation of stress on the plantar fascia.
  • Structures Affected — Achilles tendonitis affects the Achilles tendon which attaches the calf muscle to your heel, and plantar fasciitis affects the thick connective tissue that is your plantar fascia.
  • Symptoms — Achilles tendonitis presents with more aching pain and swelling, whereas plantar fasciitis tends to be more of a sharp pain with no swelling.
  • Aggravating Factors — Achilles tendonitis generally worsens throughout the day with activity, unlike plantar fasciitis which generally gets worse after resting for extended periods of time or after lots of activity.

Similarities

Because of the closeness in structures affected with both of these conditions, some of the categories we just talked about under the Differences section may also present with some similarities:

  • Location — Sometimes, plantar fasciitis pain can be located at the heel close to where the Achilles tendon attaches.
  • Cause of Pain — Like mentioned above, Achilles tendonitis usually happens due to a strain, but can also be caused by repetitive use and over-stress like in plantar fasciitis.
  • Treatment Options — Using insoles, non-steroidal anti-inflammatory drugs (AKA NSAIDs), rest, and specific exercises are used to treat both conditions (we’ll talk more about this at the end of the article).
  • Healing Timeframe — This depends on the intensity of your condition, and either could take anywhere from 2 weeks to about 10 months.

Risk Factors of Achilles Tendonitis vs. Plantar Fasciitis 

Both conditions also have similar risk factors that consist of: 

  • Different Leg Lengths — Having a leg length discrepancy can cause more pressure or strain on one foot versus the other, changing the way you walk/run and increasing your chances of straining or causing excessive stress on the structures surrounding your foot.
  • Obesity — Making your body carry excess weight will cause it to exceed its tolerances quicker, and that often happens at the lower body.
  • High Levels of Activity — Strenuous and intense exercise programs create more damage in different parts of the body, and sometimes they won’t be able to keep up with the repairs.
  • Low Levels of Activity — Sitting or staying still for long periods of time will cause your body to get stiff and consequently more prone to getting injured.
  • Weakness — Not strengthening your body through exercise and activity will make it tough for your body’s structures to handle the work it needs to do when it’s required to.
  • Change In Training Surface — Things like switching from running on grass to running on concrete can cause new stresses that the body hasn’t adapted for.
  • Increased Age — Our tendons and tissues stiffen with age, and are therefore more likely to be injured — this can largely be mitigated with consistent exercise!
  • High Arched Feet — This can create more instability in your feet, causing potential higher risk for aggravating your Achilles tendon or plantar fascia due to the increased stability demands
  • Type of Shoe — Wearing shoes with little arch support or flat soles are less supportive and could cause more unnecessary stress.
  • Change In Training Intensity — Going from one training style to a more intense one can prove too big of a jump for your Achilles tendon and plantar fascia.

Treatment Options For Achilles Tendonitis & Plantar Fasciitis

Treatment Of Plantar Fasciitis vs. Achilles Tendonitis

Treatment options for both are pretty similar, and consist of:

  • Rest — Using rest from things that make your pain worse is a good way to help the tendon or plantar fascia calm down.
  • Ice or Heat — Cold and warm therapy on the painful spot can help relieve some pain and help out with getting blood flow into the area.
  • Insoles — Wearing custom or store-bought insoles in your shoes can help support your arch and take some stress off of your tendon or plantar fascia.
  • Muscle Scraping — Using instrument assisted soft tissue mobilization techniques is a great way to provide relief for both of these conditions.
  • Exercises — A program that strengthens your feet without making things feel aggravated is a key in getting back to normal function.
  • Anti-inflammatories — Using NSAIDs like aspirin and ibuprofen can help decrease the inflammation you’re experiencing.

Conclusion

As you can see, there are many ways to tell the difference between Achilles tendonitis and plantar fasciitis.

The main thing you should look out for is where your pain is and what aggravates the pain, as this will pretty much give you your answer.

Remember, Achilles tendonitis usually hurts at the back of the heel/lower calf and gets worse with activity, and plantar fasciitis usually hurts at the bottom of your foot and gets worse after a long period of rest or right after exercising.

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Eric Richter

I'm Eric, a physiotherapist with a Bachelor’s degree in Kinesiology and a Master’s degree in Physiotherapy from the University Of Manitoba. I have enjoyed the better part of a decade working with both amateur and professional athletes, weekend warriors, everyday people, and patients at hospitals to help them take control of their pain and reach their health goals.

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