The foot check at the table

A loop race punishes feet by repetition, not distance in a single dramatic stretch: the same few hundred metres of surface, the same strike pattern, hour after hour, until a patch of skin that felt fine at lap forty is burning by lap two hundred. The short answer is that a fixed-time crew treats the foot check as routine work, done at the chair before it is asked for, because a hot spot caught early is a change of sock and a dab of lubricant, while the same hot spot ignored for three more laps is a blister that can end a night.

What actually causes a blister on a loop?

The mechanism is plain: a blister forms when repeated friction separates the upper layers of skin, and fluid fills the gap as a cushion against further damage. The American Academy of Dermatology notes that sweat and moisture lead to friction, and recommends nylon or moisture-wicking socks over cotton for that reason, which is why a foot that has been warm and damp for hours is at far more risk than a foot on a short, dry run. A fixed-time course compounds this in a specific way. The same few steps, the same angle of contact, the same seam of the same sock rub the same spot over and over, instead of the varied terrain of a trail spreading the load across different parts of the foot. By the time a runner notices the sting, the friction has usually been building for several laps already.

What does a crew actually check for?

Not an injury, most of the time. The things a crew chair looks for are small and ordinary: a sock gone damp from sweat or an aid-table spill, grit worked in at the toe seam, a red patch starting at a toe or a heel, a shoelace tied tighter on one side than the other after a stumble. None of this needs a medical tent to address. A dry pair of socks, kept ready in the crew bag, is the single most useful item at the chair, because wet skin is soft skin, and soft skin tears faster under repeated load. Lubricant or an anti-chafe balm, reapplied at the toes and heel every few hours rather than once at the start, does more good than any amount of taping done after the fact.

When does a hot spot need a dressing, not just a sock change?

General blister-care guidance is consistent on this point: once skin has visibly separated and fluid has collected, the priority shifts from prevention to protection. The American Academy of Dermatology advises against popping or draining a blister, because that can lead to infection, and suggests covering it loosely with a bandage instead: the roof of unbroken skin is the body's own best barrier. A hydrocolloid pad or a simple piece of tape smoothed flat over the spot, with no wrinkle under the shoe, lets a runner keep moving without the dressing itself becoming a second source of friction. A blister that has already torn needs the area cleaned and covered, and redness, pus, or increasing pain or swelling are the signs of infection the AAD tells people to take to a doctor, and a runner showing them needs more than a crew chair, which is a conversation for the race's medical staff, not a guess made at the table.

Why is prevention cheaper than repair?

Because every minute spent at the chair is a minute off the clock, and the clock is the whole race. The crew that checks feet at a fixed interval, every few hours rather than only when a runner asks, catches problems while they still cost thirty seconds to fix. The crew that waits for a complaint is usually fixing something that now costs five minutes, a change of shoes, and a change in gait that can cause its own new hot spot somewhere else. The same logic applies to ultrarunning more broadly: foot care rewards a plan made before the race, a spare pair of socks and a small kit packed and labelled, over any amount of improvisation once the skin has already broken.

The plain kit that covers most of a night

What shows up, in practice, at a well-run crew chair is short and unglamorous: two or three spare pairs of socks, a travel-size anti-chafe balm, hydrocolloid blister pads in a couple of sizes, a small roll of tape, scissors, and antiseptic wipes. None of it needs a medical background to use correctly for the ordinary cases, which are most of them. What it needs is attention, the same attention the table gives the broth and the lap sheet: a quick look every time the runner sits down, done before the ache becomes the story of the night.