Heat Build-Up Solutions for Running Shorts: Common Failure Causes and Fixes
Below are the failure patterns most often seen when heat build-up affects running shorts, with the correction for each.
Failure: hidden until worn
the garment traps more heat than the activity tolerates usually appears after several sessions. Because it develops slowly, it reaches the customer instead of the inspection table. Because high cadence movement plus perspiration at the waistband, target checks are made on a worn sample rather than flat fabric alone.
Cause one
hydrophobic fibre with no transport mechanism. Keep AATCC 195 moisture management tester named in the tech pack so every lot is measured the same way.

Cause two
brushed inner surface that blocks air exchange. Where running shorts is worn for road, trail and track training, set tolerances around that range of movement.
Cause three
dense double-knit construction. Any change to lightweight woven or knit body with a knit liner requires re-testing against moisture management class above 3 on AATCC 195 before bulk is released.
Correction and prevention
Apply use a wicking yarn cross-section first, then verify against moisture management class above 3 on AATCC 195 using AATCC 195 moisture management tester. Lock the corrected settings into the bulk recipe so repeat orders behave identically. Past reports from AATCC 195 moisture management tester help the mill reproduce the same recipe on the next order.