Trail Running’s Long Season: Hydration Vest Specs Buyers Compare

Trail running reached 17.2 million participants in the United States in 2025, up 6.6 percent year over year and 57 percent since 2019, according to the Outdoor Industry Association’s 2026 Running Report. Core trail runners grew 7.8 percent, which is the opposite of what is happening on the road. Retail has already responded: REI describes trail as its fastest-growing footwear category, and Brooks reported trail styles up 71 percent year over year in the second quarter of 2026.

Attachment rate is the number that matters

A divisional merchandise manager at REI told Retail Brew in September that hydration vests carry some of the highest attachment rates to trail-running footwear, meaning they are bought at the same time as the shoe, and that vest sales grew in the same range as shoes over the previous year. Trail sales at the retailer were up roughly 12 to 19 percent year to date depending on gender and category, against flat road-running growth.

For a supplier, attachment rate changes the conversation. A vest is not a standalone accessory sold on its own merits; it is part of a kit decision made in the ten minutes a customer spends at a fitting bench. That makes fit, not features, the deciding factor.

The specifications buyers compare

Four things get tested in a sample review. First, bounce: a vest loaded with two 500 ml soft flasks and a shell should stay quiet at tempo pace, which is a function of sternum strap geometry and how the front panels are cut, not of fabric weight. Second, sizing ladder: a 5, 8 and 12 litre family covers most of the market, and a women’s-specific torso length is now a requirement rather than an option. Third, pocket layout: a front stretch pocket that swallows a phone, a soft flask pocket that can be reached without unclipping, and a rear compartment that takes a folded shell.

Fourth, hardware and finishing: reflective trim on the front and back, a pole attachment that does not require a separate quiver, and edge binding that does not abrade a base layer over 20 km.

Sourcing takeaway

Quote the vest as a three-size family with one shared pattern and two torso lengths, and send a bounce-test video with the sample rather than a fabric specification sheet. Retail buyers evaluate this category at the fitting bench, and the supplier who supplies a sizing card and a wash-care label that survives 30 cycles removes the main objection. Keep the first order narrow, three sizes and two colourways, and use the reorder window in late winter, when trail race registration opens, to add the larger volume.

Developing a hydration vest programme? See the trail running range.

Sources

Outdoor Industry Association, “2026 Running Report”, https://outdoorindustry.org/2026-running-report/

Retail Brew, “Trail running hits its stride”, 8 Sep 2026, https://www.retailbrew.com/stories/trail-running-hits-its-stride