Repeat 400's can be used as an assessment to measure both your anaerobic fitness (running speed) and your aerobic fitness (endurance)
In order to perform the test, find a 400 metre oval or track. Choose the number of repetitions you would like to perform. It is recommended that beginners, (levels 1-2) perform 4-5 repetitions, intermediates (levels 3-4) perform 6-7 repetitions whilst advanced (levels 5-6) perform 8-10 repetitions.
Shorter rests 60 seconds to 90 seconds increase the cardiovascular component of the assessment whilst longer rest 120-210 give the test a higher anaerobic or speed component