Why Runners Get Plantar Fasciitis and What to Do About It

Plantar fasciitis is inflammation of the thick band of tissue connecting your heel bone to your toes. It affects 2.5-6% of runners and is the most common cause of heel pain. The hallmark symptom is sharp, stabbing pain under the heel with the first steps in the morning or after sitting for long periods. A prospective study of runners found that weekly mileage above 40 km increases the odds of developing plantar fasciitis by 6 times compared to running 6-20 km per week. Prior history of plantar fasciitis is the strongest predictor of recurrence (5.1x higher risk). Treatment with the strongest evidence: plantar fascia-specific stretching and calf stretching, which provide both short- and long-term pain reduction. Most runners can continue running at reduced volume during treatment. Full resolution typically takes 6-12 months with conservative management.

Understanding Plantar Fasciitis in Runners

What is the plantar fascia? A thick band of connective tissue that runs along the bottom of the foot from the heel bone (calcaneus) to the base of the toes. It supports the arch and absorbs shock during running. Each running stride loads the plantar fascia with forces of 1.5-3x body weight.

Key risk factors from research: A 2024 prospective study following runners for 12 months found that runners covering 41+ km per week had 6 times higher odds of developing plantar fasciitis. Prior history increased reinjury odds by 5.1x. Females showed twice the risk of males. Interestingly, most commonly cited biomechanical factors (vertical loading rates, footstrike patterns) showed no significant association. One protective factor identified: greater ankle abduction (slight toe-out during stance) appeared to reduce risk.

Training load is the dominant factor. The research suggests approximately 40 km per week as a reasonably safe upper limit. Above this threshold, the cumulative stress on the plantar fascia exceeds its ability to recover between runs.

An Arion Running Analysis can measure your ground contact patterns and foot rotation angles, which may help identify whether your running mechanics place additional load on the plantar fascia.

Treatment and Prevention

Evidence-Based Treatment (Start Here)

  • Plantar fascia-specific stretch: Cross one leg over the other, pull the toes back toward the shin until you feel a stretch along the arch. Hold 30 seconds, repeat 10 times. Do this before the first steps in the morning and after any period of sitting. This has Level I evidence for pain reduction.
  • Calf stretching (gastrocnemius and soleus): Wall lean stretch with knee straight (gastrocnemius) and bent (soleus). Hold 30 seconds each, 3 reps, twice daily. Tight calves increase strain on the plantar fascia during push-off.
  • Towel curls and marble pickups: 3 x 20 reps daily. Strengthens the intrinsic foot muscles that support the arch and reduce plantar fascia loading.
  • Frozen water bottle roll: Roll the arch over a frozen bottle for 10 minutes after running. Combines stretching with anti-inflammatory cold therapy.

Progressive Loading (Weeks 2-8)

  • Single-leg calf raises: Start with 3 x 10, progress to 3 x 15. Eccentric emphasis (slow 3-second lowering). Builds the calf strength that offloads the plantar fascia during running.
  • Arch strengthening (short foot exercise): While standing, try to shorten your foot by drawing the ball of the foot toward the heel without curling the toes. Hold 10 seconds, 10 reps, 3 times daily. This activates the intrinsic foot muscles.
  • Gradual return to running volume: Reduce weekly mileage by 30-50% during the acute phase. Increase by no more than 10% per week once pain is consistently below 3/10 during running.

Additional Interventions

  • Night splints: A 1-3 month programme of night splints is recommended for runners with consistent first-step morning pain. Night splints maintain dorsiflexion to prevent the plantar fascia from shortening overnight.
  • Taping: Low-dye taping or kinesiology tape along the arch provides short-term pain relief and can be used during running to offload the plantar fascia.
  • Structured insoles: An insole with firm arch support distributes pressure across the plantar fascia rather than concentrating it at the heel insertion point. The Shapes HYROX Edition provides structured arch support and a deep heel cup that reduces peak plantar pressure during running. This complements stretching and strengthening but does not replace them.

When to See a Professional

  • If pain does not improve after 6-8 weeks of consistent stretching and load management.
  • If pain is severe enough to alter your walking pattern.
  • If you feel a sudden pop or tearing sensation in the arch (possible plantar fascia rupture, which requires immediate medical evaluation).

FAQ

What causes plantar fasciitis in runners?

The dominant risk factor is training volume. Research shows that running 41+ km per week increases plantar fasciitis risk by 6 times. Other factors: previous plantar fasciitis (5.1x reinjury risk), female sex (2x risk), tight calf muscles, and age. Contrary to popular belief, footstrike pattern and vertical loading rates showed no significant association with plantar fasciitis development in prospective research.

Can I keep running with plantar fasciitis?

Usually yes, at reduced volume. Reduce weekly mileage by 30-50% and avoid running through sharp pain. If pain stays below 3/10 during running and does not worsen in the 24 hours afterward, you can continue. Combine running with daily stretching and strengthening. Complete rest is generally not necessary and may slow recovery by reducing the load stimulus the tendon needs to heal.

How long does plantar fasciitis take to heal?

Most cases resolve in 6-12 months with consistent conservative treatment (stretching, strengthening, load management). Significant pain improvement often occurs within 6-8 weeks. However, reinjury rates are high if runners return to full volume too quickly. Increase mileage by no more than 10% per week once pain is consistently manageable.

Do insoles help with plantar fasciitis?

Insoles with firm arch support help distribute plantar pressure more evenly and reduce peak stress at the heel insertion. They are most effective when combined with stretching and strengthening, not as a standalone treatment. A structured insole with a deep heel cup is more effective than a purely cushioned insole. Clinical practice guidelines include orthotic support as a recommended component of conservative management.

What exercises prevent plantar fasciitis?

The most effective prevention exercises: plantar fascia-specific stretching (10 x 30-second holds daily), calf stretching (gastrocnemius and soleus), single-leg calf raises (eccentric emphasis), and intrinsic foot strengthening (towel curls, short foot exercises). Keeping weekly running volume below 40 km and increasing by no more than 10% per week are the most important structural prevention measures.

How much running is too much for plantar fasciitis risk?

Research suggests approximately 40 km per week is a reasonably safe upper limit. Above this threshold, plantar fasciitis risk increases by 6 times. Moderate running (6-20 km per week) showed no higher risk than non-running. The risk is not from running itself but from cumulative load exceeding the tissue's recovery capacity.

Sources

  1. Running Distance and Biomechanical Risk Factors for Plantar Fasciitis: A 1-yr Prospective Cohort Study - PMC (2024)
  2. Comprehensive Review and Evidence-Based Treatment Framework for Plantar Fasciitis Diagnosis and Management - PMC (2025)
  3. Heel Pain - Plantar Fasciitis: Clinical Practice Guidelines Revision 2023 - JOSPT