Give an example of a mechanical, dietary, and psychological ergogenic aid and how it is either beneficial or harmful to athletic performance.

Ergonomic aids are those that are made or used to maximize productivity at the same time that it facilitates the work. So, a mechanical ergonomic aid could be an aerodynamic bicycle, it is purely beneficial for athletic performance as it reduces air friction and increases speed. A dietary ergonomic aid can be caffeine. Caffeine increases the use of fat as energy and increases the level of attention but, on the other hand, it may cause dehydration and elevated blood pressure. A psychological ergonomic aid may be music. Music works by calming an athlete before an important competition or boost someone's energy. It may also distract the athlete from its task and therefore be harmful.

Dip, snus and chew are the main types of smokeless tobacco