i dont know much about active wear, but i feel like most of the time, when you´re alt, you will always look a bit alt even if your clothes aren´t. it´s just the vibe. i would say keep your usual color schemes or maybe get some black activewear and some "edgy" trainers. a friend of mine that dresses more goth-ish recently got like some black-silver asics for example. Also! hair does a lot. when you got dark or colorful hair or a cool hairstyle it helps.
i´m also thinking...maybe some cool sweat band would be nice? there´s lots of emo ones too :3