The 85/15 polyester-spandex blend is knit tighter than standard rash guard fabric to give true muscle compression rather than just a snug fit, which is what athletes are actually paying for when they order compression rather than a plain rash guard.
Fight teams ordering a matched training kit — top and shorts together — are the main buyers, since a full set under one sublimation run keeps colors and branding consistent across the whole squad.
Turn compression garments inside out before washing to protect the printed surface, and skip fabric softener, which coats the fibers and reduces the moisture-wicking effect over repeated washes.