DOWNHILL SHEAR15,200 FT OF LOSS
Natural Chimneys Park, Virginia · September · 100 mi
Foot care for Grindstone 100 mi
Grindstone 100 mi is hours on feet. Shear adds up.
Threat matrix
What Grindstone 100 mi does to feet.
Every line below is computed from published course data or written by PR Run and labeled as such.
- Hours on feet100 miles inside a 36 hour limit. Every hour adds shear, swelling, and sock saturation.Course data
- Total descent load15,200 ft of cumulative descent. Nail beds and forefoot pay for all of it.Course data
- Heat and sweatSeptember highs reach 85 degrees F. Sweat saturates socks, skin softens, friction climbs.Course data
- Downhill shearMile 81.5 to 89.5 drops 2,600 ft at 6.2 percent average grade. Toes hit the front of the shoe, heels lift.Course data
- Technical groundTechnicality 6/10. Rock strikes, side loading, and constant foot correction grind the same spots.Course data
- Night hoursA 36 hour window means hours of taping in the dark with cold hands. Practice it that way.Course data
Downhill shear
Where gravity works on your toes.
Sustained descents pulled straight from the elevation profile. Pretape before these, not after.
The schedule
Where you sit down and take the shoes off.
Set your goal time. The clocks, the stop plan, and the kit all move together.
- Aid 1MI 1009:00
Socks and a look
10 mi since the last stop, cutoff 5 h.
- Socks off. Check the pressure points and swap if the pair is wet.
- Aid 2MI 2012:00
Socks and a look
10 mi since the last stop, cutoff 9 h.
- Socks off. Check the pressure points and swap if the pair is wet.
- Aid 3MI 3015:00
Shoes off
10 mi since the last stop, 1,750 ft of descent into it, cutoff 12 h.
- Shoes and socks off. Pat completely dry, fresh socks, powder if the last pair was soaked.
- Check toes and nail beds. 1,750 ft of descent came into this stop.
- Aid 4MI 4018:00
Eyes only
10 mi since the last stop, cutoff 15 h.
- Eyes only. Feel for hot spots through the sock and keep moving.
- Aid 5MI 5021:01
Eyes only
10 mi since the last stop, cutoff 18 h.
- Eyes only. Feel for hot spots through the sock and keep moving.
- Aid 6MI 6000:01
Shoes off
10 mi since the last stop, 2,050 ft of descent into it, cutoff 21 h, late race, feet already soft.
- Shoes and socks off. Pat completely dry, fresh socks, powder if the last pair was soaked.
- Check toes and nail beds. 2,050 ft of descent came into this stop.
- Aid 7MI 7003:01
Socks and a look
10 mi since the last stop, 200 ft of descent into it, cutoff 24 h, late race, feet already soft.
- Socks off. Check the pressure points and swap if the pair is wet.
- Aid 8MI 8006:00
Eyes only
10 mi since the last stop, cutoff 27 h, late race, feet already soft.
- Eyes only. Feel for hot spots through the sock and keep moving.
- Aid 9MI 9009:00
Shoes off
10 mi since the last stop, 2,600 ft of descent into it, cutoff 31 h, late race, feet already soft.
- Shoes and socks off. Pat completely dry, fresh socks, powder if the last pair was soaked.
- Check toes and nail beds. 2,600 ft of descent came into this stop.
- FinishMI 10012:00
Eyes only
10 mi since the last stop, cutoff 36 h, late race, feet already soft.
- Eyes only. Feel for hot spots through the sock and keep moving.
Checked on top of the essentials for Grindstone 100 mi.
Vest / pack
Crew bag
Drop bag
Kit deltas
What Grindstone 100 mi adds to the standard kit.
- Powder and a moisture barrierSweat is the friction multiplier on this course.
- Pretape for toes and heelsLong descents load the front of the shoe and lift the heel.
- Light you can tape byTaping in the dark with cold hands is a different skill than taping at your kitchen table.
- Half size up in the crew bagFeet swell over the back half. A tight shoe at midnight ends races.
- Moleskin for pressure pointsRock strikes and side loading build hot spots off the usual map.
Shoes
What survives this course.
Matched on terrain, technicality, and distance. Fit still beats every spec, so try them on a long run first.
Crew
What your crew needs on paper.
Two plates. On the left, the race-specific notes that never make it into the standard script. On the right, the printable card your crew reads at two in the morning under a headlamp.
Race day notes
- Crux near Reddish Knob and the Camp Todd to North River Gap night section near mile 65. Plan foot work before the field splits.
- Surfaces: 85% trail / 10% jeep / 5% paved. Match lugs and tape adhesion to the dominant surface.
- Air band 45°F to 85°F. Crew should carry dry socks and skin lube when heat or rain is in range.
- Cutoff 36 hours. Longer stops only where the schedule has real buffer.
- Educational only. Test every tape, sock, and shoe combination on long runs before race day.
Where you sit down
- Aid 3MI 30
- Aid 6MI 60
- Aid 9MI 90
Print card
A single sheet your crew reads at two in the morning: the stop script, the mandatory kit, and the calls that pull the runner. Print it, laminate it, staple it to the drop bag.
Crew foot care card
Station script. Three to eight minutes if organized.
- Runner sits. Shoes and socks off both feet.
- Inspect: hot spots, maceration, nails, blisters.
- Clean with wipe. Pat completely dry. No tape on damp skin.
- Treat hot spots first. Drain blisters only if necessary with clean technique.
- Fresh socks. Relace shoes. Runner stands and tests before leaving.
Mandatory kit
- Leukotape, kinesiology tape, wipes, blister patches, moleskin
- Scissors, nail clippers, lubricant, powder, spare socks (2+)
- Antibiotic ointment, gloves, cohesive wrap, small towel
When to pull runner: spreading redness, loss of feeling, gait collapse, unmanageable pain.
PR Run · pr.run/foot-care
FAQ
Grindstone 100 mi foot questions.
- 01
Where should I stop for foot care at Grindstone 100 mi?
Aid 3 at mile 30, Aid 6 at mile 60, Aid 9 at mile 90. Those stops carry the most ground and descent behind them, so a sock change and a tape check pay for the minutes they cost.
- 02
Which section of Grindstone 100 mi wrecks feet?
Mile 81.5 to 89.5 drops 2,600 ft at 6.2 percent average grade. That is where toes meet the front of the shoe and heels start to lift. Pretape before it, not after.
- 03
How do I keep my feet dry at Grindstone 100 mi?
September highs reach 85 degrees F. Sweat saturates socks, skin softens, friction climbs. Change socks at every stop you can, run powder or a moisture barrier, and lean forward when you dump water on your head so it misses your shoes.
- 04
How many sock changes for Grindstone 100 mi?
Plan one at every foot stop you have access to, and carry one spare pair beyond that. 100 miles inside 36 hours is long enough that dry socks are faster than the five minutes they cost.
- 05
How do I stop blisters at Grindstone 100 mi?
Start from the biggest threat on this course. 100 miles inside a 36 hour limit. Every hour adds shear, swelling, and sock saturation. Fit the shoe with room for swelling, pretape the spots that have blistered on you before, keep grit out, and change socks at every stop you have access to. Blisters come from pressure, friction, and moisture, so remove whichever one this course hands you the most of.
- 06
What foot care kit should I pack for Grindstone 100 mi?
Beyond the standard kit, this course calls for powder and a moisture barrier, pretape for toes and heels, light you can tape by, half size up in the crew bag, moleskin for pressure points. Sweat is the friction multiplier on this course.
- 07
What shoes work for Grindstone 100 mi?
85% trail / 10% jeep / 5% paved at technicality 6/10 points toward Norda 055, Hoka Mafate X, Hoka Mafate X. Whatever you pick, race it on a long run first and leave room for feet that swell over the back half.
Educational only. Not medical advice. Persistent pain, infection, or numbness: see a podiatrist or sports medicine clinician.
Train for it
Feet get you to the finish. The plan gets you there on the clock.
Foot care is one system on Grindstone 100 mi. Climbs, descents, heat, fueling, and cutoffs are the rest of it.