Who do somme athletes use steriods illealy​

I am a bit confused by your grammar, but I am guessing it was just a typo and you are asking why some athletes use steroids illegally. (no worries!)

Some athletes take a form of steroids — known as anabolic-androgenic steroids or just anabolic steroids — to increase their muscle mass and strength. It depends on the steroid, but most athletes who do take them are trying to improve their performance. I cannot answer as to why they do it illegally, it depends on what is going on in there head, but the above is why they may. Hope this helps, have a nice day!