The multi-stage fitness test, also known as the bleep test, beep test, pacer test, Leger-test or 20-m shuttle run test, is a series of stages that have different tasks sometimes used by sports coaches and trainers to estimate an athlete's VO2 max (maximum oxygen uptake).The pacer test is "progressive aerobic cardiovascular endurance test". The test is especially useful for players of sports such as rugby, football, Australian rules football, Gaelic football, hurling, hockey, netball, handball, tennis, squash, and fitness testing in schools and colleges plus many other sports; employed by many international sporting teams as an accurate test of cardiovascular fitness, one of the more important components of Fitness. The test was created in 1982 by Luc Leger, University of Montreal[1] and published in 1983 with a starting speed of 8 km/h and stages of 2 min duration. The test was re-published in the European Journal of Applied Physiology in 1988 in its present form with a starting speed of 8.5 km/h and 1 min stages under the name "The multistage 20 metre shuttle run test for aerobic fitness".[2] Result equivalences between slightly modified versions are well explained by Tomkinson et al. in 2003.[3]