Ultra Running Training Apparel: Fabric and Fit Guide

Ultra running training apparel needs to perform across a wide range of conditions: 90-degree summer long runs, pre-dawn mountain sessions in 40-degree temperatures, six-hour back-to-back weekend efforts, and daily recovery runs. The right fabric choice makes each context more comfortable and the wrong one creates chafing, overheating, or shivering that degrades the training quality. Bear Grips Pro Shops offers custom-printed training apparel across three main fabric categories.

Performance Polyester: The Best Fabric for Ultra Running Training

Performance polyester, specifically the moisture-wicking variety, is the best choice for high-intensity and long-duration training runs. The mechanism is straightforward: the synthetic fibers do not absorb water. Instead, they wick sweat to the fabric surface where it evaporates. The result is a shirt that stays lighter and dries faster than cotton throughout a training session.

For ultra running, where training runs can last three to eight hours, the weight difference between a wet cotton shirt and a dry performance shirt becomes significant. A soaked cotton shirt can add 8 to 12 ounces over the course of a long run. On a flat road long run that is a minor inconvenience. On technical trail with elevation change, it affects energy expenditure in a measurable way.

Performance shirts also dry fast enough between efforts that back-to-back training days (a common ultra running preparation method) do not require as many shirts in rotation. A performance shirt rinsed after Saturday's long run is dry and ready for Sunday's recovery run without laundering.

The best performance polyester options in the Bear Grips Pro Shops catalog for ultra running training:

• Men's Moisture-Wicking Tee (Sport-Tek, PosiCharge): The default training shirt. Available in 20-plus colors, true to size, lightweight.
• Men's Moisture Wicking Long Sleeve (Sport-Tek): For cooler training conditions.
• Ladies' Moisture Wicking Tee (Sport-Tek): The women's athletic cut version.

Tri-Blend Fabric: Between Performance and Everyday Comfort

Tri-blend fabric (typically a mix of cotton, polyester, and rayon) sits between pure performance polyester and pure cotton in terms of moisture management and comfort. It does not wick as aggressively as a PosiCharge performance tee, but it is softer, has a more relaxed drape, and feels less synthetic against the skin.

Tri-blend shirts in the Bear Grips Pro Shops catalog that work for moderate-pace training and everyday club wear:

• Men's Premium Triblend Crew Tee (Next Level): A popular choice for ultra runners who want a shirt that transitions from the trail to a coffee shop without looking like race gear. The slightly vintage aesthetic and soft hand make it wearable as lifestyle apparel. Not ideal for high-intensity efforts where aggressive wicking is needed.
• Women's Premium Triblend Tee (Next Level): The women's version in the same construction.
• Women's Premium Triblend Racerback Tank (Next Level): A racerback tri-blend option for warm-weather runs where the softer fabric feel is preferred over pure performance polyester.

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Cotton for Everyday and Post-Run Ultra Running Wear

Cotton has a specific role in the ultra running wardrobe: it is not a training fabric but it is the best fabric for post-run comfort, everyday club wear, and finisher shirts that runners keep as keepsakes.

The argument for cotton in the right context: after a six-hour training run, the last thing most ultra runners want is to change back into another synthetic fabric. Cotton is breathable at rest, soft against skin that may be salt-crusted and slightly irritated from a long effort, and it does not trap warmth the way fleece does when you just need a casual layer.

Cotton options in the catalog for ultra running post-run and everyday use:

• Airlume Cotton Athletic Tee (Bear Grips): Ring-spun cotton with a clean print surface. The most popular everyday club shirt for ultra runners. Soft, well-fitted, available in a wide color range.
• Long Sleeve Cotton Shirt (Bella+Canvas): For cool-weather days when a cotton long sleeve is the right post-run layer before switching to a hoodie.
• Premium CVC Jersey Tee (Next Level): A cotton-polyester blend that gives the softness of cotton with slightly better moisture management. Good for moderate-pace efforts where pure performance is not the priority.

Sizing Ultra Running Apparel for Athletic Body Types

Ultra runners have a wide range of body types. Elite mountain runners often run lean and long through the torso. Larger-build endurance athletes carry more through the chest and back. Sizing guidance by fabric type:

• Performance tees (Sport-Tek): Run true to size through the chest with a slightly fitted cut through the waist. Athletes who prefer a looser fit during training should size up one. Athletes who run lean and want a fitted training look can order their standard size.
• Cotton tees (Bear Grips Airlume): Run true to size for most body types. A slight relaxed fit at standard sizing. Athletes who want a very fitted look may want to size down one. Athletes who want an oversized casual look can size up.
• Leggings (Bear Grips): The high-waist pocket leggings and capri leggings run true to size. The Signature Seamless Leggings run slightly compressed through the waist and hips, which is intentional for the seamless construction. Sizing up one is recommended for anyone at the top end of a size range.

Every product page at shops.beargrips.com includes a detailed size chart with body measurements. For club orders where sizes are being collected from members, sharing the product page link so each member can check the chart against their own measurements produces the most accurate size distribution.

Frequently Asked Questions

What fabric is best for ultra running training shirts?

Moisture-wicking polyester (like Sport-Tek PosiCharge) is the best choice for training runs. It wicks sweat to the surface and dries fast, keeping the shirt lighter and more comfortable than cotton over a multi-hour effort. Cotton is better suited for post-run wear and everyday club shirts.

Do performance polyester shirts feel different from cotton on long runs?

Yes. Performance polyester is lighter and dries faster during extended efforts. Cotton absorbs sweat and stays wet, which adds weight and can cause chafing on longer runs. The difference becomes most noticeable on efforts over two hours in warm conditions.

What size should ultra runners order in performance tees?

Performance tees (Sport-Tek) run true to size through the chest with a slightly fitted waist. Runners who prefer a looser training fit should size up one. The size chart on each product page lists chest measurements to help confirm the right size.

Can ultra running coaches get custom-printed training shirts for their athletes?

Yes. Custom printed training shirts with a coaching brand logo or program name are available with no minimum. A coach with 20 athletes can order 20 shirts in 20 different sizes through the store link model where each athlete orders their own.