Final answer:
An ergogenic aid is a substance or phenomenon that enhances athletic performance. It can include substances like anabolic steroids and erythropoietin, which are used to build muscle mass and increase endurance. These aids can have serious health risks and are often banned in sports.
Step-by-step explanation:
An ergogenic aid is any substance or phenomenon that enhances performance in sports or exercise. It can include substances like anabolic steroids, erythropoietin, and human growth hormone, which are used to build muscle mass and increase endurance. These aids are often banned by governing bodies in sports and can have serious health risks. Examples of ergogenic aids also include caffeine, which can improve performance in both aerobic and anaerobic conditions.