If you've ever taken your first steps out of bed and felt a sharp stab in your heel, you already know what plantar fasciitis feels like. It's one of the most common overuse injuries we see in runners, and it's also one of the most misunderstood — most people either ignore it until it's chronic, or they stop running entirely when they don't need to.
Here's what's actually going on, why it happens, and what to do about it.
What is it?
The plantar fascia is a thick band of connective tissue that runs along the bottom of your foot, from your heel to your toes. It acts like a bowstring, supporting your arch and absorbing load every time your foot hits the ground. Plantar fasciitis is a breakdown in that tissue, technically more of a degeneration than pure "inflammation" Every step we take and even just standing puts stress on the platar fascia, which is why it can be so stubborn to resolve.
What Causes It?
Plantar fasciitis is almost always a symptom of too much load, too fast, with not enough tissue capacity to handle it. Common contributors we see in the studio:
Rapid mileage increases. Jumping from 15 to 30 miles a week in a month is a classic setup.
Weak intrinsic foot and calf muscles. If your foot and calf can't absorb shock efficiently, the fascia picks up the slack. This is also commonly associated with poor glute medius development.
Poor ankle mobility. Limited dorsiflexion forces the foot to compensate, adding strain to the arch. The ankle must be able to dorsiflex for the muscles of the calf to absorb the ground force.
Worn-out or poorly fitted shoes. Lost cushioning and support shift more load onto the plantar fascia. Also, too much cushion can lead to weakness in the foot, as i mentioned in my blog about plated shoes.
Running form issues. Overstriding and excessive heel striking increase impact forces at the exact point where the fascia attaches to the heel.
Tight calves and Achilles. Reduced ankle flexibility pulls on the fascia indirectly through the kinetic chain. Tight or short calf muscles can sometimes be an indicator of weak calves, weak dorsiflexors, or both.
Standing on hard surfaces for long hours outside of running. This adds to daily cumulative load your foot already can't handle.
It's rarely one single cause — it's usually a stack of small deficits that finally exceeds what your tissue can tolerate.
How do you Prevent It?
Prevention comes down to building capacity before you need it, not reacting after pain shows up.
Progress mileage gradually. Keep weekly increases to roughly 10% and build in cutback weeks every 3-4 weeks.
Strengthen your feet and calves. Calf raises, toe yoga, short foot exercises, and single-leg balance work all build the tissue resilience that protects the fascia.
Work on ankle mobility. Banded ankle dorsiflexion drills and calf stretching keep your ankle moving well enough that your foot isn't compensating.
Replace shoes before they're dead. As a rule of thumb, retire running shoes every 300-500 miles depending on the model and your body weight.
Clean up your form. A slightly higher cadence and a foot strike closer to under your hips (rather than way out in front) reduces braking forces at the heel. You should feel light when your foot strikes the ground, achieved by landing on the mid to forefoot.
Don't skip the warm-up. Cold tissue is stiffer tissue. A few minutes of dynamic movement before you run goes a long way.
How do you Fix It?
If you're already dealing with it, the good news is that plantar fasciitis responds well to a consistent, patient approach. What doesn't work is total rest followed by jumping right back into your old mileage — that just resets the cycle.
Load management first. Reduce mileage and intensity, but stay active with cross-training like swimming or cycling to maintain fitness without the impact.
Calf and foot strengthening. Heavy, slow-loaded calf raises (including with a bent knee to target the soleus) have strong research support for tendon and fascia issues.
Manual work and rolling. Rolling the arch on a frozen water bottle or lacrosse ball can help manage symptoms, especially first thing in the morning.
Stretch the calf and fascia directly. A simple towel stretch for the calf, plus dorsiflexing the toes to stretch the fascia itself, done consistently, makes a real difference.
Consider a night splint or supportive footwear to keep the fascia from tightening up overnight, which is often what causes that brutal first-step pain.
Get it assessed if it's not improving in 2-3 weeks. A physical therapist or sports medicine provider can rule out other issues (like a heel stress fracture) and build a personalized rehab plan.
Plantar fasciitis is frustrating because it's slow to heal, but it's rarely permanent if you respect the process. Build the capacity on the front end, and you'll spend a lot less time managing it on the back end.
Josh Kober, ACSM Certified Personal Trainer, RRCA Certified Running Coach — Co-Owner and Head Coach at Glide Training Co.