For this achievement you must get one gold medal for each type of activity, and there are six hobbies and pastimes-- Shooting Range, Flight School, Offroad Race, Sea Race, Street Race, and Triathlon) in GTA 5. All of them unlock by completing story missions. The shooting range is the most difficult to get a gold medal in as you will have to get a certain number of points within a time limit. Shoot fast and always hit the yellow center area of the targets. In the flight school, simply beat the time limit in the first tutorial. In races and triathlon, you must finish first to get a gold medal. Street races become available by completing Hao's side mission. However, the mission requires you to get a gold medal in a street race. Therefore, don't have to complete any further races to get the "Multi-Disciplined" achievement. Note: Hao's side mission only becomes available from 8 p.m. to 5 a.m. while playing as Franklin, and is shown as a question mark on the map. For the other hobbies and pastimes, you can select any desired character.