Between the organisation of the worlds of sports in Antiquity and today there are several similarities. Top athletes were surrounded by attendants and trainers. The latter determined a strict training schedule and a diet for the athlete. Each trainer had his own opinion about the ideal nutrition for athletes and had his own set of quack remedies, e.g. herbal potions for runners against stabbing pains in the spleen.
Potions were also used to patch up wounded athletes, so they could participate in the next round of the contest. Roman gladiators drank ashes mixed with water against bruises and abdominal cramps. Every trainer considered himself a sports doctor. Serious doctors, like Galenus, condemned their practices and thought that athletes ruined their own body.
Real doping (forbidden performance-enhancing drugs) did not exist, because no potion or medicine was forbidden. Most plant with elements that can actually enhance performances originate from South-America, moreover, and where hence not known in Antiquity. There was a prohibition of black magic, though. Ancient athletes, who were even more superstitious than their modern counterparts, tried to curse their opponents to enhance their own chances of victory.