Plantar Fasciitis vs Heel Spur vs Achilles Tendonitis: How to Tell the Difference

At a Glance: Three Conditions, One Heel

Plantar fasciitis, heel spurs, and Achilles tendonitis all produce heel pain, but they originate from different structures, follow different pain patterns, and respond to different treatments. Pain location and timing are the fastest ways to narrow down which one you have.

All three share morning stiffness and tight calves as contributing factors, which is why so many people struggle to identify which one they have.

What Each Condition Actually Is

Plantar fasciitis is damaged tissue under the foot, a heel spur is a calcium growth on the heel bone, and Achilles tendonitis is an overloaded tendon behind the ankle. All three center on the calcaneus: the plantar fascia attaches to the bottom, the Achilles tendon attaches to the back, and heel spurs can form at either attachment point.

Plantar fasciitis

Plantar fasciitis develops when the connective tissue under your foot becomes damaged from repeated strain, producing stabbing pain at the bottom of your heel.

The plantar fascia works like a bowstring supporting your arch. When strain exceeds the tissue's capacity to repair, small tears develop at the calcaneal attachment, starting a cycle of tearing and incomplete healing. For more detail, see our complete plantar fasciitis guide.

Heel spur

A heel spur is a bony calcium growth that forms gradually in response to chronic tension at a tissue attachment point on the heel.

When the plantar fascia or Achilles tendon pulls repeatedly on the calcaneus, the body deposits calcium to reinforce the stressed area. Approximately 50% of plantar fasciitis patients have heel spurs on imaging, yet only about 5% of people with spurs experience pain from the growth itself.^[1] The spur forms within the fascial origin and typically does not press on surrounding nerves or soft tissue, which is why most spurs are incidental findings. Learn more about heel spur causes and treatment.

Achilles tendonitis

Achilles tendonitis happens when the tendon connecting your calf muscles to the rear of your heel becomes overloaded and begins to degenerate, causing pain behind the ankle or in the lower calf.

The Achilles is the thickest tendon in the body, transmitting force for every push-off during walking and running. When overloading exceeds recovery capacity, collagen fibers disorganize and break down. See our Achilles tendonitis guide.

Where It Hurts: Symptoms Side by Side

Plantar fasciitis, heel spurs, and Achilles tendonitis share morning stiffness and calf tightness, but the differences show up in where the pain concentrates, when it peaks, and what makes it better or worse. Recognizing these patterns is the first step toward identifying which condition is driving your symptoms.

Morning pain. Plantar fasciitis produces the sharpest pain on your earliest steps, typically easing within 5-10 minutes as gentle movement elongates the contracted fascia and increases blood flow to the inflamed tissue. Achilles tendonitis causes stiffness behind the heel that loosens gradually. Heel spur discomfort follows no reliable morning pattern, because the spur's irritation depends on its size, position, and whether surrounding soft tissue is inflamed.

Pain during activity. Plantar fasciitis tends to improve with gentle movement but flares after prolonged activity. Achilles tendonitis follows the opposite pattern: the tendon may feel better after a warm-up, but pain builds with continued running or jumping. Heel spur symptoms depend on footwear and activity because the spur can hurt in two different ways: a stiff shoe heel or hard surface pressing directly on the growth, or the fascia and Achilles pulling where the spur formed. Because either kind of irritation can trigger pain, heel spur discomfort doesn't follow the clear patterns that PF and Achilles do.

Pain location. The single most useful differentiator. Plantar fasciitis concentrates at the bottom of the heel. Achilles tendonitis concentrates behind the heel or above it. Heel spur pain can occur at either site but tends to feel pinpoint rather than diffuse, because the irritation originates from a localized bony prominence pressing on a small area of surrounding soft tissue.

The calf connection. Tight calf muscles shorten the gastrocnemius and soleus (the two large muscles in the back of your lower leg), which increases tension on the Achilles tendon. That tension pulls harder on the calcaneus, which in turn increases strain on the plantar fascia attached to the other side of the same bone. Miami's warm climate compounds this: year-round activity without a cold-weather rest period means these tissues rarely get a recovery window.

What starts as occasional stiffness in one area can become near-constant discomfort as cumulative calf tension loads all three structures. This shared kinetic chain explains why many people develop more than one condition simultaneously.

How to Tell Which One You Have

Three at-home assessments plus two quick physical checks can help you narrow down which condition is driving your heel pain. If you've been stretching, icing, or wearing orthotics for weeks without clear improvement, the treatment may be targeting the wrong structure. In our experience, combining multiple tests gives a much clearer picture than relying on any single sign.

The Location Test

Point to where it hurts.

• Bottom of your heel or toward the arch: Suggests plantar fasciitis.
• Behind your heel or above it toward the calf: Suggests Achilles tendonitis.
• A very specific pinpoint spot: May indicate a symptomatic heel spur, though imaging would be needed to confirm.

The Timing Test

When is your pain worst?

• First morning steps, easing after 5-10 minutes: Classic plantar fasciitis. The fascia tightens overnight and the first load produces sharp pain.
• Stiffness that eases, then returns with activity: Classic Achilles tendonitis. The tendon loosens with light movement but breaks down under sustained load.
• Intermittent, no clear pattern: Less specific. May reflect a heel spur or co-occurrence of multiple conditions.

The Windlass Test (plantar fasciitis check)

Sit down and pull your big toe back toward your shin. If this reproduces or worsens pain at the bottom of the foot, the plantar fascia is likely involved. If it produces no change, plantar fasciitis is less likely. This test tensions the fascia across the arch, replicating the load pattern that triggers PF pain.

The Single-Leg Heel Raise (Achilles check)

Stand on one foot and slowly rise up onto your toes, then lower back down. If this reproduces pain behind your heel or in the lower calf, the Achilles tendon is likely involved. If you can complete 10 raises pain-free, Achilles tendonitis is less likely. If walking Brickell's concrete sidewalks in flat shoes triggers bottom-of-heel pain but this test is painless, that points away from the Achilles.

Consistent results pointing to one condition give you a strong starting point. Mixed results may indicate overlapping conditions. Track your pain for 3-5 days (when, where, what triggered it) before seeing a provider.

These assessments may help you understand your symptoms. They do not replace a professional evaluation.

Why the Right Diagnosis Matters for Treatment

Applying the wrong treatment protocol can delay recovery or actively worsen your symptoms, because each of these three conditions responds to a fundamentally different approach and requires its own combination of loading, support, and muscular work.

Plantar fasciitis. Calf and fascia stretching, supportive footwear, and night splints form the foundation. Conservative care resolves more than 9 in 10 cases without surgery.^[3] TheraMax (robotic muscular therapy) is designed to target the calf muscles with sustained pressure, reaching deep restrictions that stretching alone often cannot. TheraMax is not covered by insurance and is a newer modality. See plantar fasciitis treatment in Miami.

Heel spur. Treat the underlying condition, not the spur. If plantar fasciitis is contributing to your pain, PF treatment typically resolves symptoms even while the spur remains on imaging. TheraMax is designed to address the muscular dysfunction that contributed to spur formation, though it cannot dissolve or remove the spur itself. Stretching, orthotics, and activity modification support recovery.^[3] See heel spur treatment in Miami.

Achilles tendonitis. Eccentric loading exercises are the gold standard because the controlled lengthening stimulates aligned collagen remodeling in the damaged tendon.^[2] If your Dolphin Expressway commute means 45 minutes of sitting, calf tightening loads your Achilles before you even start your workout. TheraMax is designed to target that tension, complementing (not replacing) the eccentric loading the tendon needs. See Achilles tendonitis treatment in Miami.

In our clinical experience, the most common mistakes are:

• Complete rest for plantar fasciitis. Total inactivity makes PF worse. The tissue contracts without controlled loading.
• Treating the spur instead of the fasciitis. If the spur is incidental, removing it surgically does nothing for the tissue problem.
• Using PF protocols for Achilles tendonitis. The tendon needs progressive loading, not offloading.
• Relying on orthotics alone for any of the three. Inserts redistribute pressure but do not release the fascial or muscular restrictions contributing to the pain.

What to Do This Week Based on Your Results

Once you have a good idea from the tests above of which condition you're dealing with, the next step is condition-specific home care. Matching the right protocol to the right condition is what separates progress from months of frustration.

If your tests point to plantar fasciitis

Start with calf stretches and towel curls twice daily, switch to shoes with firm arch support, and ice the heel for 15 minutes after activity. Miami's year-round warm weather means you can do these stretches outdoors at any point in the year. Avoid walking barefoot on hard floors, especially first thing in the morning.

Most people see improvement within 2-4 weeks of consistent home care. If pain persists beyond that window, a professional assessment can confirm the diagnosis and determine whether night splints, targeted manual work, or TheraMax is the right next step. See plantar fasciitis treatment options in Miami.

If your tests point to Achilles tendonitis

Begin eccentric heel drops: stand on the edge of a step, slowly lower your heel below the edge over 3-5 seconds, then rise back up using your other foot. Do 3 sets of 15, twice daily. Reduce running volume by at least 50% and avoid hill workouts and speed sessions until pain during activity drops below a 3/10.

Expect 6-12 weeks for tendon remodeling with consistent loading. If pain worsens or plateaus after 3 weeks of eccentric work, a sports medicine provider can rule out partial tears and adjust your protocol. See Achilles tendonitis treatment options in Miami.

If your tests point to a heel spur

Treat the underlying soft tissue condition first. If the Windlass Test was positive, follow the plantar fasciitis plan above. If heel raises reproduced your pain, follow the Achilles tendonitis plan. Imaging can confirm spur presence, but remember: treatment targets the tissue dysfunction, not the spur itself. If conservative care resolves your pain while the spur remains on X-ray, you have your answer. See heel spur treatment options in Miami.

If your results are mixed or unclear

Multiple conditions often coexist, especially when calf tightness is the shared driver. Start with the calf stretching protocol (it benefits all three conditions) and track your symptoms for one week: note pain location, timing, and severity each morning and evening. If the pattern doesn't clarify, a professional evaluation can distinguish overlapping conditions and prioritize treatment. In Miami, call (786) 480-0026 to discuss whether a targeted assessment makes sense for your situation.

When Home Care Is Not Enough

Most heel pain responds to the right home protocol within 2-4 weeks. Seek professional evaluation if any of these apply:

• No improvement after 2-3 weeks of consistent, condition-specific home care
• Pain is getting worse despite treatment, not just staying the same
• Mixed test results that make it hard to identify a single condition
• Morning pain regularly exceeds 6/10 and prevents normal activity
• You've been through multiple treatments (stretching, orthotics, injections) without lasting improvement

A clinician can use imaging and physical examination to confirm which condition is driving your symptoms and build a targeted recovery plan. Once you have a diagnosis, TheraMax is designed to target the muscular restrictions that may contribute to each of these conditions. Most clients complete their protocol in 4-6 sessions. Explore our foot and ankle treatment options in Miami or call (786) 480-0026.

Frequently Asked Questions

These questions come from the most common points of confusion we see in people dealing with heel pain in the Miami area.