The shorts you wear at hour 14 of a 100-miler are not the shorts you wear at hour 4 of a 50K. Inseam length, liner construction, and pocket layout matter increasingly as the race gets longer. Five picks below.
The picks
Patagonia
Patagonia Strider Pro 7"
The 7-inch inseam is the sweet spot for ultrarunning — short enough to move freely, long enough to prevent inner-thigh chafe at hour 12. Built-in liner doubles as compression.
- 7-inch inseam
- Built-in compression liner
- Three rear pockets + side stash
- Patagonia lifetime warranty
Janji
Janji AFO 5.5" Middle Short
The most-loved running short on Strava. 5.5-inch inseam, four storage pockets, the most thoughtful liner in the category. Janji's also the only running brand whose mission you can root for.
- 5.5-inch inseam
- 4 zip + drop pockets
- Compression liner with key clip
- Made for running, not aesthetics
Path Projects
Path Projects Sykes PX 7"
Five pockets including two thigh-zip pockets that fit a phone or 4 gels. The 100-mile shorts. Designed by ultrarunners; tested at Hardrock and Western States.
- 7-inch inseam
- 5 pockets including dual thigh zips
- Mesh liner — anti-chafe
- Designed for 100-mile races
Salomon
Salomon Sense Aero 5" Shorts
The race-day short. Lightweight, minimalist, and the inseam runs short enough to feel barely-there. For 50K and faster races where weight matters.
- 5-inch inseam
- Minimalist liner
- 2 mesh pockets
- Lightest in test (95g)
Brooks
Brooks Sherpa 7" 2-in-1
Solid mid-tier 2-in-1 shorts. Liner is comfortable; the outer short has good range of motion. Best at this price point.
- 7-inch inseam
- 2-in-1 design (compression liner + outer)
- 3 pockets
- Brooks reflective hits
Inseam length by distance
- 5 inch: 5K to 50K. Light, fast, more freedom of stride.
- 7 inch: 50-mile to 100-mile. Long enough to prevent inner-thigh chafe; pocket capacity grows.
- 9 inch: 100M+ in cold conditions. More coverage; better for night sections; can chafe in hot weather.
The chafe rule
Pre-apply Body Glide on the inner thigh, the lower abdomen (where the waistband sits), and the inner sit-bones (where the liner sits) before any race over 4 hours. Reapply at every crew stop. The shorts only do half the work; lubrication does the other half.
Pockets — the modern requirement
Modern ultra shorts have 3–5 pockets. The functional minimum: one rear zip pocket (key/cash), two side-stash pockets (gels), one thigh pocket (phone). If your shorts have fewer than 3 pockets, your vest is doing more work than it needs to.