Running & conditioning · multi-interval
Four 5 minute blocks of 30 seconds easy, 20 seconds moderate and 10 seconds flat out, with 2 minutes recovery between blocks.
Gunnarsson & Bangsbo, J Appl Physiol 2012;113(1):16-24: low, moderate and high speed running for 30, 20 and 10 s in three or four 5-min intervals with 2 min of recovery