The Enemy Below
A blister might seem like a minor annoyance, but in an ultramarathon, it can quickly become debilitating. Friction, moisture, and heat are the primary culprits. Your goal is to minimize all three.
Shoe Fit is Paramount
Your trail shoes must fit perfectly. They should be snug enough in the heel and midfoot to prevent sliding, but roomy enough in the toe box to allow for the inevitable swelling that occurs during a long run. Consider sizing up half a size for 100-milers.
The Right Socks
Never wear cotton socks. Choose synthetic or merino wool blends that wick moisture away from the skin. Many ultra runners swear by toe socks (like Injinji) to prevent skin-on-skin friction between the toes.
Lubrication and Taping
Pre-treat known hotspots before the race. Apply a generous layer of anti-chafe balm (like Squirrel's Nut Butter or Trail Toes) to your feet. Some runners prefer taping vulnerable areas with kinesiology tape or specialized blister tape.
Mid-Race Maintenance
If you feel a hot spot developing, stop immediately. Don't wait until the next aid station. Clean the area, dry it, reapply lubricant, or tape it. Changing into a fresh, dry pair of socks halfway through a race can feel like a miracle.
Treating a Blister
If you get a blister, you have two choices: leave it or drain it. If it's small and not painful, leave it alone. If it's large and fluid-filled, sterilize a needle, puncture the edge, gently press the fluid out, and cover it securely with a blister patch.