Plantar fasciitis causes pain under the heel; Achilles tendinopathy causes pain at the back of the heel or just above it. They are separate conditions, but they share risk factors, are mechanically linked through the heel bone and calf, and both respond best to progressive strengthening rather than rest.
About one in three people experience heel pain at some point. This guide from the foot and ankle team at Sports Orthopedics Institute, Bengaluru explains how to tell the two conditions apart, how they're connected, and which treatments the evidence supports.
Key takeaways
- Location tells them apart: under the heel = plantar fasciitis; back of the heel or above = Achilles tendinopathy.
- They're linked: the Achilles tendon and plantar fascia work as one system through the heel bone and calf.
- Both are overload problems – more about wear and failed healing than simple inflammation.
- Strength training is the core treatment for both.
- Injections differ: PRP may help plantar fasciitis but didn't help Achilles tendinopathy in a large trial; steroid injections should be avoided in the Achilles tendon.
- Most people recover without surgery, though it can take several months.
How to tell them apart
|
|
Plantar fasciitis |
Achilles tendinopathy |
|---|---|---|
|
Where it hurts |
Under the heel, towards the inner side |
Back of the heel or 2–6 cm above it |
|
Typical pattern |
Sharp pain with the first steps in the morning or after sitting |
Stiffness and pain in the morning and at the start of activity |
|
Who gets it |
Adults 40–60, people with higher body weight, those standing all day, runners |
Runners, cricketers, badminton players, active adults 30–50 |
|
Main treatment |
Calf and foot strengthening, stretching, heel cups, shockwave |
Progressive calf strengthening (heavy slow or eccentric) |
Plantar Fasciitis
The plantar fascia is a thick band of tissue running from the heel bone to the toes, supporting the arch. When it is overloaded, it thickens and becomes painful where it attaches to the heel. Doctors increasingly call it plantar fasciopathy, because inflammation isn't the main problem.
Risk factors
- Higher body weight – a meta-analysis of 51 studies found a BMI over 27 was the only clinical factor consistently linked to plantar fasciitis (odds ratio 3.7), with the strongest effect in non-athletes (BJSM, 2016)
- Limited ankle bend (dorsiflexion) – in a matched case-control study, this was the most important risk factor, alongside obesity and standing for most of the workday (JBJS, 2003)
- Running and long periods standing, particularly on hard floors
- Flat or high-arched feet
Symptoms
- Sharp pain under the heel with the first steps in the morning or after resting
- Pain that eases after walking a few minutes but returns after long periods on your feet
- Tenderness under the inner front of the heel
Achilles Tendinopathy
The Achilles tendon connects the calf muscles to the heel bone and lets you push off when walking, running and climbing stairs. Overload causes structural changes and pain, either in the middle of the tendon (mid-portion) or where it attaches to the heel (insertional).
Risk factors
- Sudden increases in running, jumping or sport
- Age over 35
- Higher body weight, diabetes and high cholesterol
- Fluoroquinolone antibiotics (such as ciprofloxacin) and steroid injections near the tendon
- Inflammatory arthritis, which can cause pain where the tendon attaches
Symptoms
- Pain and stiffness at the back of the heel or above it, worst in the morning
- Pain at the start of activity that may ease, then returns afterwards
- A thickened, tender tendon
Sudden severe pain with a “kick” sensation is different – it may be a rupture and needs same-day assessment.
How the Two Are Connected
The calf muscles, Achilles tendon, heel bone and plantar fascia work together as one system – sometimes called the Achilles-calcaneal-plantar system.
- A shared anatomical link: a systematic review found studies describing tissue continuity between the Achilles tendon and the plantar fascia around the heel bone (via the paratenon and the heel's outer layer), a connection that becomes thinner with age (Life, 2021).
- A mechanical link: tension in the Achilles tendon increases tension in the plantar fascia, and their stiffness changes together as the knee and ankle move (Life, 2021).
- Shared risk factors: in a case-control study of 108 people with plantar fasciitis and 114 with Achilles tendinopathy, abnormal foot posture – feet that roll in too much or too little – raised the risk of both by about three to four times (Johannsen et al.).
What this means for treatment: both conditions benefit from restoring calf strength and ankle movement, and a problem in one part of the system can load the other. That's why treatment for either often includes calf strengthening and attention to footwear and foot posture.
The evidence on tight calves is mixed: limited ankle bend was a strong risk factor for plantar fasciitis in one study, but not in the combined study above.
Diagnosis
Both conditions are usually diagnosed from your symptoms and an examination – where it hurts, what triggers it, and how the calf, ankle and foot move.
- Ultrasound shows thickening of the plantar fascia or Achilles tendon, rules out a tear, and can guide injections
- X-ray may show a heel spur or a bony bump at the back of the heel; a spur is common and often not the cause of pain
- MRI is used for unclear cases, such as a suspected stress fracture of the heel bone
- Blood tests if inflammatory arthritis is suspected – for example, pain in both heels with other joint pain
Other causes of heel pain include heel fat pad problems, nerve entrapment (such as Baxter's nerve), stress fractures and bursitis.
Treating Plantar Fasciitis
First-line treatment
- High-load strength training: slow single-leg heel raises on a step with a rolled towel under the toes. In a randomised trial of 48 patients, this gave better foot function at 3 months than plantar-fascia stretching (both groups used heel inserts); by 12 months both groups had improved similarly (Scand J Med Sci Sports, 2015)
- Plantar fascia and calf stretching, especially before the first steps of the day
- Heel cups or inserts and supportive footwear; avoid walking barefoot on hard floors
- Load management: reduce long periods of standing or running for a while
- Weight management where relevant
- Night splints for persistent morning pain
If it isn't improving after about 3 months
- Shockwave therapy (ESWT): ranked as the most effective option for pain at 6 months in a network meta-analysis of eight treatments (J Cell Physiol, 2019), and gave better pain scores than steroid injection at 6 months in a meta-analysis of 18 studies (Foot, 2023)
- PRP injection: in the same meta-analysis, PRP gave better pain scores than steroid injection at 3 and 6 months
- Steroid injection: effective for short-term relief but without clear long-term benefit, and carries risks such as heel fat pad thinning and plantar fascia rupture (Arch Orthop Trauma Surg, 2018) – use sparingly
Surgery
Rarely needed. A partial plantar fascia release or a calf (gastrocnemius) release may be considered after 6–12 months of well-supervised treatment without improvement.
Treating Achilles Tendinopathy
First-line treatment
Progressive tendon-loading exercise is the only treatment given the strongest grade of recommendation in the 2024 US physiotherapy clinical practice guideline (JOSPT, 2024).
- Heavy slow resistance or eccentric heel drops: in a randomised trial, both produced equally good, lasting improvements at one year, with better adherence to heavy slow resistance (Am J Sports Med, 2015)
- For insertional pain: keep heel drops on flat ground rather than dropping below a step
- Load management: reduce hills, speedwork and jumping; running can often continue if pain stays mild and settles by the next morning
- Heel lifts in the short term
If it isn't improving after about 3 months
- Shockwave therapy as an add-on to exercise
- Avoid PRP: a 240-patient trial found a PRP injection no better than a sham injection (JAMA, 2021)
- Avoid steroid injections into the tendon, which may weaken it
Surgery
Considered after at least 6 months of good-quality rehabilitation without improvement – for example, cleaning up the diseased tendon or removing a heel bump. See our guide to Achilles tendinopathy surgery.
Recovery Time
Both conditions improve slowly. With consistent treatment, most people notice improvement within 6–12 weeks, and recover over 3–6 months. Plantar fasciitis can persist longer – around 40% of patients still have some symptoms two years after diagnosis (Rathleff et al.) – which is why early, structured treatment matters.
Prevention
- Build up gradually when starting or increasing running, walking or sport
- Strengthen your calves and feet regularly with heel raises, even when pain-free
- Keep your ankles moving well with calf stretches if they are stiff
- Wear supportive footwear; avoid long periods barefoot on hard floors
- Manage body weight
- Act early – heel pain caught in the first weeks settles much faster
When to See a Specialist
- Heel pain lasting more than 4–6 weeks despite self-care
- Pain at night or at rest, or numbness or tingling in the foot
- Swelling, redness, or pain in both heels with other joint pain
- Sudden severe pain at the back of the heel with weakness – seek same-day care
How Sports Orthopedics Institute Can Help
Our foot and ankle team in HSR Layout, Bengaluru, led by Dr Naveen Kumar L.V., offers accurate diagnosis with ultrasound, structured strengthening programmes, shockwave therapy and, when needed, surgery.
Book at sportsorthopedics.in or call +91 6364538660 / +91 9008520831.
Frequently Asked Questions
How do I know if it's plantar fasciitis or Achilles tendinopathy?
Location is the main clue: pain under the heel, worst with the first steps of the morning, suggests plantar fasciitis; pain at the back of the heel or above it, with morning stiffness, suggests Achilles tendinopathy. You can have both.
Are the two conditions connected?
Yes. The Achilles tendon and plantar fascia are linked through the heel bone and work together during walking and running. They also share risk factors such as foot posture and body weight.
What are the first signs of Achilles tendon problems?
Stiffness or pain at the back of the heel first thing in the morning or at the start of a run, and tenderness when the tendon is squeezed.
How long does heel pain take to heal?
Most people improve within 6–12 weeks and recover over 3–6 months with consistent treatment. Some cases take longer.
Which exercises help?
For both: slow, progressive heel raises. For plantar fasciitis, add a rolled towel under the toes and plantar fascia stretches. For Achilles tendinopathy, heavy slow calf raises or eccentric heel drops.
Are injections helpful?
For plantar fasciitis, shockwave and PRP have better medium-term results than steroid injections.
Do I need surgery?
Rarely. Surgery is only considered after at least 6 months of well-supervised treatment without improvement.
References
- Weinrich L, et al. Does the calcaneus serve as hypomochlion within the lower limb by a myofascial connection? A systematic review. Life, 2021;11(8):745.
- Johannsen FE, et al. Foot posture and ankle dorsiflexion as risk factors for developing Achilles tendinopathy and plantar fasciitis: a case-control study.
- Higher body mass index is associated with plantar fasciopathy: systematic review and meta-analysis. Br J Sports Med, 2016.
- Riddle DL, et al. Risk factors for plantar fasciitis: a matched case-control study. J Bone Joint Surg Am, 2003;85:872–877.
- Rathleff MS, et al. High-load strength training improves outcome in patients with plantar fasciitis. Scand J Med Sci Sports, 2015;25(3):e292–e300.
- Comparison of efficacy of eight treatments for plantar fasciitis: a network meta-analysis. J Cell Physiol, 2019.
- The role of corticosteroid injections in treating plantar fasciitis: a systematic review and meta-analysis. Foot, 2023.
- Chimenti RL, et al. Midportion Achilles tendinopathy clinical practice guideline – revision 2024. JOSPT, 2024.
- Beyer R, et al. Heavy slow resistance versus eccentric training for Achilles tendinopathy. Am J Sports Med, 2015.
- Kearney RS, et al. PRP vs sham injection in chronic midportion Achilles tendinopathy. JAMA, 2021.
Disclaimer: This article is for general information and does not replace advice from a qualified healthcare professional.