There's a specific failure mode every runner knows: the shirt comes out of the wash smelling fine, you put it on, you warm up — and the smell comes roaring back. The garment was never actually clean.

Understanding why explains almost everything about caring for technical fabric.

Why synthetics trap odor#

Performance fabrics are polyester, nylon, and elastane. All are plastics, and all are hydrophobic — they repel water. That's the entire point: sweat gets wicked along the fiber surface to evaporate instead of soaking in.

But body oils are not water. Oil bonds readily to a plastic surface, and bacteria feed on those oils. Water-based detergent struggles to reach an oily residue clinging to a water-repelling fiber. So a normal wash removes the sweat and leaves the oil — and with it, the bacteria that produce the smell as soon as you heat back up.

Cotton doesn't do this because it absorbs, and washing flushes an absorbent fiber properly.

What actually removes it#

Use an enzyme detergent, and use less of it. Lipase and protease break down the oils and proteins that plain surfactants leave behind. Counterintuitively, extra detergent makes things worse — undissolved excess builds a film that holds more oil.

Stop using fabric softener. Completely. This is the most important rule for activewear. Softener works by depositing a waxy cationic layer on fibers. On technical fabric that layer clogs the spaces that make wicking work, permanently reduces breathability, and seals existing odor in. Softener is how a good running shirt becomes a bad one.

Wash inside out. The oils are on the inside surface. Turning the garment exposes them directly to water and detergent.

Don't let it sit. A damp gym bag is an incubator. If you can't wash within a day, at minimum hang it to dry — bacteria need moisture to multiply.

For garments already gone bad: soak an hour in cold water with half a cup of white vinegar, then wash as normal with enzyme detergent and no softener. Vinegar strips the mineral and oil buildup. Repeat weekly if you train daily. In hard Des Moines water this soak makes a bigger difference than it would elsewhere — see our hard water guide.

What's killing the stretch#

Elastane (Lycra, spandex) is what gives leggings their recovery, and it has exactly two enemies.

Heat. Elastane fibers are set under tension during manufacturing. Heat relaxes them, and once relaxed they don't recover. This is why leggings go baggy at the knees and waistbands stop gripping. A hot dryer will do this in a handful of cycles.

Wash cold. Air dry, or tumble on the lowest heat your machine offers. Technical fabric dries fast anyway — hanging costs you almost nothing in time.

Chlorine bleach. It dissolves elastane outright. Never use it on anything with stretch. For swimwear, rinse in cool water immediately after the pool; chlorinated water does the same damage more slowly.

A few more things that matter#

• Zip all zippers before washing. An open zipper acts like a saw against soft knit fabric in a tumbling drum.
• Mesh bags for bras and light knits — hooks catch, and straps stretch when they wrap around an agitator.
• Wash with like fabrics. Towels and cotton shed lint that clings to synthetics and abrades them.
• Skip dryer sheets too. Same waxy coating problem as liquid softener. Use wool dryer balls if you want to speed drying.

Waterproof and water-resistant shells#

Rain jackets need washing more often than people think — accumulated body oil is what makes a DWR finish stop beading. Use a technical cleaner (not standard detergent, which leaves surfactants that attract water), then tumble on low heat, which reactivates the finish. If beading doesn't return, the coating needs reapplying, not more washing.

Our machines let you control wash temperature and dryer heat independently, which is exactly what technical fabrics need — cold wash, low or no heat dry. Find your nearest store on the locations page.