Variable Time 4x 6:00 cont. (3:00/2:00/1:00) rest 3:00 to 6:00 rep 1&3 20/22/24 rep 2&4 22/24/26 These are 4x 6min continuous sets with rate increases along the way. R20 reps start at 2k + 17-18 sec. R22 reps start at 2k + 15-16 sec. Increase pace at least -2 sec from previous for each rate increase.