Plantar Fasciitis.
Plantar fasciitis is the most common cause of heel pain in runners, characterised by a sharp, stabbing pain under the heel — worst with the first steps of the morning and after prolonged sitting. It is a degenerative condition of the plantar fascia (not inflammatory, despite the '-itis' suffix), and it responds best to progressive loading protocols rather than rest alone.
Overview
The plantar fascia is a thick band of connective tissue connecting the calcaneus (heel bone) to the metatarsal heads at the base of the toes. It acts as a windlass mechanism during push-off, storing and releasing elastic energy with each stride — absorbing forces of 2-3 times body weight during running. Plantar fasciitis (more accurately termed 'plantar fasciopathy' because the condition is degenerative rather than inflammatory) develops when repetitive loading exceeds the tissue's capacity to recover, causing collagen disorganisation, micro-tears and failed healing. It is the most common cause of heel pain in runners and the third most common running injury overall.
Causes and risk factors
The most common triggers are rapid increases in running volume (more than 10% per week), excessive time on feet on hard surfaces (standing occupations compound running load), tight calf muscles (particularly the soleus), high BMI, and flat or excessively arched foot types. Runners who switch abruptly from cushioned shoes to minimalist or zero-drop footwear are at significantly elevated risk because the plantar fascia absorbs more load in lower-drop shoes. The condition is more common in runners over 40 due to age-related reduction in fascial elasticity and collagen quality.
Symptoms
A sharp, stabbing pain localised under the medial heel, worst with the first steps of the morning (the classic 'first-step pain') and after prolonged sitting or standing. The pain typically improves with movement as the fascia warms up and becomes more pliable, but returns after rest or prolonged loading. In advanced cases, pain may persist throughout running and begin to affect walking. The condition can last months or years if not addressed with progressive loading — passive rest alone typically does not resolve plantar fasciopathy because the tissue needs mechanical stimulus to remodel.
The loading protocol
The Rathleff protocol — heavy slow resistance training for the calf and plantar fascia — is the most effective evidence-based treatment, outperforming corticosteroid injections, stretching alone and shockwave therapy in randomised trials. Stand on a step with a towel rolled under your toes to tension the plantar fascia, raise onto the ball of your foot using both feet, then lower slowly on the affected side over 3 seconds. Perform 3 sets of 12 repetitions, twice daily, for a minimum of 12 weeks. Progressive overload by adding weight incrementally using a loaded backpack (start with 2-5 kg and increase as the exercise becomes manageable).
Supporting treatments
Night splints hold the foot in slight dorsiflexion to maintain fascial length overnight and reduce morning pain severity. Foot intrinsic strengthening (towel scrunches for 3x30 seconds, short-foot exercises for 3x10 repetitions) rebuilds the muscular support system of the arch. Calf stretching targets both the straight-leg gastrocnemius and bent-knee soleus (held for 30-60 seconds, 3 repetitions each). Ice massage with a frozen water bottle for 10 minutes after runs reduces post-activity pain. Avoid going barefoot on hard floors during recovery — supportive slippers or sandals protect the fascia from cold-start loading.
Recovery and return to running
Plantar fasciitis is one of the slowest running injuries to resolve — expect 8-12 weeks of consistent daily loading protocol before significant improvement begins, with full resolution typically taking 3-6 months. Continue running at reduced volume (50-70% of normal) if pain stays below 3/10 during and after runs and morning pain does not worsen week over week. Full return to training should be gradual with 10% weekly volume increases. Maintain calf and foot intrinsic strength work indefinitely after recovery — runners who stop the Rathleff protocol after symptom resolution have significantly higher recurrence rates.
Frequently asked questions
What does plantar fasciitis feel like?
Plantar fasciitis presents as a sharp, stabbing pain under the medial heel — classically at its worst with the very first steps of the morning or after prolonged sitting. The pain typically eases once the fascia warms up and becomes more pliable, but returns after rest or a long period of standing. If pain is only at one pinpoint spot rather than diffuse along the arch, consider a possible calcaneal stress fracture and seek imaging.
How long does plantar fasciitis take to heal?
Plantar fasciopathy is one of the slowest-resolving running injuries. Most runners see meaningful improvement after 8-12 weeks of consistent daily loading (the Rathleff protocol) and full resolution in 3-6 months. Passive rest alone typically does not resolve it because the degenerative fascia needs progressive mechanical load to remodel — stopping exercise just deconditions the tissue further.
Can I keep running with plantar fasciitis?
Yes, in most cases — if you can keep pain below 3/10 during and after runs and morning pain is not worsening week-over-week. Reduce volume by 30-50% initially, run on softer surfaces, and pair every run with the daily calf-plus-fascia loading protocol. Stop immediately if pain breaks into the heel from the arch or if a single pinpoint tender spot develops — those are signs of progression toward a heel spur or calcaneal stress reaction.
What's the best stretch for plantar fasciitis?
Heavy slow resistance loading (Rathleff protocol) outperforms stretching in randomised trials. Stand on a step with a rolled towel under the toes of the affected side to tension the fascia, raise onto the balls of both feet, then lower slowly on the affected side over 3 seconds — 3 sets of 12, twice daily for 12 weeks. Add a bent-knee soleus stretch (30 seconds × 3) and a straight-leg gastrocnemius stretch (30 seconds × 3) as supporting work, not the primary treatment.
Do I need custom orthotics for plantar fasciitis?
Not as a first-line treatment. Off-the-shelf arch-supporting insoles combined with a consistent loading protocol resolve the majority of cases. Custom orthotics are reasonable if symptoms persist beyond 12 weeks of diligent Rathleff loading, if there is a significant leg-length discrepancy or a structural foot deformity, or if you have a standing occupation that makes symptom management difficult. Orthotics are a support tool, not a cure — the fascia still needs to be loaded.
Is plantar fasciitis the same as a heel spur?
No, but they are commonly related. A heel spur is a bony outgrowth at the calcaneus that forms over time in response to chronic traction from the plantar fascia. The spur itself is usually painless — the pain comes from the fascia's ongoing degeneration at that attachment point. Surgical spur removal without addressing the fascia rarely resolves symptoms; the correct treatment is loading the fascia regardless of whether a spur is visible on X-ray.
Why is plantar fasciitis worst in the morning?
During sleep the foot rests in plantarflexion, which allows the plantar fascia and Achilles to shorten slightly. The first weight-bearing steps of the morning stretch the degenerative tissue abruptly, producing the characteristic sharp first-step pain. A night splint that holds the foot in slight dorsiflexion overnight maintains fascial length and measurably reduces morning pain within 2-3 weeks of consistent use.
This article is for educational purposes only and does not constitute medical advice. If you are experiencing pain or injury, consult a qualified sports medicine physician or physiotherapist before modifying your training. Read our full medical disclaimer.