The test involves running continuously between two points that are 20 m apart from side to side.
The runs are synchronized with a pre-recorded tape (see link), which plays beeps at set intervals.
As the test proceeds, the interval between each successive beep decreases, forcing the athletes to increase their speed over the course of the test until it is impossible to keep in sync with the recording
The recording is typically structured into 21 ‘levels’, each lasting around 62 s.
The interval of beeps is calculated as requiring a speed at the start of 8.5 km/h increasing by 0.5 km/h with each level thereafter.
The progression from one level to the next is signaled by 3 quick beeps.
The highest level attained before failing to keep up is recorded as the score for that test.