LRjiujitsu, i take back my previous post. after wearing the guardian for kickboxing tonight i'm not sure if the medium will fit you. the shorts i think would be fine, but the cup may be too big. halfway through class i found the cup to bother me because it was digging a bit into the inside of my legs. with a 28 waist i will make the assumption that you are shorter/smaller than i am so for you this may be a bigger issue. for reference, i'm 5'8", 155 lbs, athletic build.