Plantar Fasciitis: The Heavy Slow Resistance Protocol for Faster Early Relief

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The Rathleff protocol

Rathleff and colleagues randomised plantar fasciitis patients to either standard care (stretching) or heavy slow resistance training. The heavy slow resistance group showed substantially greater improvement at the 3-month primary endpoint, though by 12 months both groups had converged to similar outcomes Rathleff 2015. The programme the trial tested is below; a physiotherapist can adapt it to your foot and your pain:

• Setup: stand on a step with a folded towel under the toes, raising them to maximum dorsiflexion. This puts the plantar fascia under stretch from the start.
• Movement: rise up onto toes over 3 seconds (concentric), hold 2 seconds at top, lower over 3 seconds (eccentric). Single-leg on the affected side.
• Load: a weighted backpack, starting at a weight that could be lifted about 12 times (12RM) and progressing to heavier loads with fewer repetitions over the programme.
• Dose: every second day, 3 sets to near failure.
• Duration: 12 weeks in the trial.

“High-load strength training targeting the plantar fascia produced significantly greater pain reduction than plantar-specific stretching at the 3-month primary endpoint. By 6 and 12 months, both groups had converged, with no significant difference between them.”

— Rathleff et al., Scand J Med Sci Sports, 2015 view source

Other interventions that help

• Soleus stretching (knee-bent calf stretch). 60 seconds per side, 3-5 times daily.
• Night splints for adults with severe morning pain. Keeps foot in slight dorsiflexion overnight.
• Plantar-fascia specific stretching: sit, cross affected foot over opposite knee, pull toes back into dorsiflexion, hold 30 seconds, 3 sets, 3 times daily.
• Supportive footwear during acute phase. Skip barefoot walking and minimal shoes while symptoms are acute.

Avoid cortisone (mostly)

Cortisone injections provide rapid short-term pain relief, but trial evidence shows that relief fades within a few weeks and the injections do not outperform placebo by 12 weeks McMillan 2012. The injections also carry small but real risks of plantar fascia rupture, a complication documented in case reports rather than in that trial itself, which recorded no adverse events. Whether an injection makes sense for you is a decision to make with your doctor, weighing short-lived relief against that risk.

What doesn’t work

• Rest alone — symptoms often return when activity resumes.
• NSAID-only management — symptom relief without addressing tissue change.
• Ultrasound therapy — trials don’t show benefit beyond placebo.
• Custom orthotics as first-line — off-the-shelf inserts perform similarly in head-to-head trials.

Practical takeaways

• Heavy slow resistance had the best short-term results in Rathleff’s comparison: toes-on-towel single-leg calf raises with progressive load, every second day, for 12 weeks.
• Add soleus stretching, plantar-fascia stretching, supportive footwear.
• Night splints help severe morning pain.
• Skip cortisone except as last resort — relief fades fast and there is a rupture risk.
• Expect 6-12 months for full resolution. The protocol works; the timeline is long.

References