Variable Time 3x 10 min cont. (4m/3m/2m/1m) rest 3-6min 63% watts start at rates 22/24/26/28 (2 sets) 67% watts start at rates 24/26/28/30 (1 set) Start targets = 2k PB pace +15 at r22, and +13 at r24. Increase pace at least -2 seconds (~3%) from previous with each rate increase.