The Hidden Systemic Roots of Plantar Fasciitis

Plantar fasciitis is rarely just a foot problem. While most runners treat it as a localized injury requiring rest, ice, and orthotics, Dr. Mandy Riehl argues that these interventions often ignore the underlying systemic mechanics. By failing to address the true cause, whether it is an inflammatory issue in the fascia or a nerve issue originating in the spine, runners frequently trap themselves in a cycle of chronic pain and deconditioning. The competitive advantage lies in shifting from passive, symptomatic relief to active, load-based resilience. Those who learn to distinguish between these two types of injury and prioritize systemic strength over quick fixes will recover faster and build a more durable foundation for the long term.

Key Insights & Analysis

The Failure of the Rest and Support Loop

Conventional wisdom for foot pain involves immediate rest, orthotics, and nighttime splints. Dr. Riehl suggests this approach often backfires. By treating the foot as a passive structure that needs protection, runners inadvertently induce stiffness and dependency. Orthotics, while potentially useful as a short-term crutch for acute instability, can lead to long-term atrophy of the intrinsic foot muscles.

The problem is when people spend 10, 20 years in them and then they don't have that foot strength because they're not stressing their foot. And unfortunately with plantar fasciitis in particular I can't tell you how many patients I've had that not only have had orthotics forever, but they use them inside.

-- Dr. Mandy Riehl

When you remove the stress required to maintain foot strength, you create a system that is less capable of absorbing the repetitive impact of running. Over time, this makes the foot more susceptible to injury, creating a feedback loop where the solution, support, becomes the primary driver of the problem.

Distinguishing True Inflammation from Nerve Irritation

A critical insight is that plantar fasciitis is often a misnomer for nerve-related pain. Dr. Riehl identifies two distinct categories: true plantar fasciitis, which is inflammation of the fascia, and fake or pseudo plantar fasciitis, which is nerve irritation.

This distinction is vital because the treatments are diametrically opposed. Stretching, which might provide temporary relief for a tight calf, can severely aggravate nerve-mediated pain. If a runner experiences shifting pain, concurrent SI joint issues, or symptoms that migrate between feet, the source is likely neurological, originating in the spine. Treating this as a simple tissue-inflammation issue is a common error that prevents healing.

The Power of Novel Stimuli

The system responds to variety. Repetitive, monotonous loading patterns, such as running the same mileage on the same surfaces in the same shoes, reduce the body's ability to adapt to novel forces. Dr. Riehl emphasizes that resilience is built through adventure days and varied training stimuli.

If you do lots of things then your body is capable of doing lots of things. So I like doing that. There was a time in my life where it was metronome and trained for one specific thing and there's no variety there. That's fine. That's a circle of running for sure. But having the variety to basically do whatever you want whenever you want it is awesome.

-- Dr. Mandy Riehl

By exposing the feet to different surfaces, shoe types, and movement patterns, runners force the body to maintain a broader range of functional capabilities. This prevents the brittleness that occurs when a system is optimized for only one specific, narrow stressor.

Key Action Items

• Audit your footwear: Stop relying on orthotics for daily wear unless prescribed for acute injury. If you have been using them for years, begin a transition to more natural foot movement to regain intrinsic muscle strength.
• Implement Big Toe Cueing: During all single-leg weighted exercises like RDLs or split squats, focus on driving your big toe into the ground. This improves joint centration and ensures the entire kinetic chain is working in the correct order of operations.
• Prioritize Heavy Single-Leg Loading: Shift focus from generic foot stretches to heavy, barefoot-friendly, single-leg strength training. This builds the structural armor necessary to handle running loads.
• Adopt Adventure Training: Integrate variety into your weekly training. Mix surfaces, paces, and shoe types to prevent repetitive stress patterns. This builds long-term systemic resilience that prevents injuries before they start.
• Stop Stretching the Fascia: If you are experiencing pain, avoid the urge to stretch the bottom of your foot. If the injury is nerve-mediated, this will only increase irritation and prolong recovery.
• Seek Diagnostic Clarity: If your pain does not improve within a few weeks, stop the current treatment. If symptoms switch sides or correlate with back or SI joint discomfort, consult a professional to rule out nerve-mediated issues rather than continuing to treat the foot as an isolated tissue problem.