Behind every horserace are strict rules such as: jockeys must have the weight marked in the program, each horse participates in one weekly or fortnightly race, as it is subject to great exertion. The Mexico City hipodrome has a school for jockeys where the minimum age is 15 and a weight of 45 kg. Training lasts 4 hours daily and they are taught differnt types of bits, ways in which to hold the reins and place the stirrups. After six months they are sent to the stables in order that they may attain their jockey rank. Here pupils must free themselves of three stars: the first is lost when winning 5 races, the second after 35 triumphs and the third after a year of practice.