From Velo News February 2018 issue: Sepp Kuss's Favorite Over-Under Workout: Two 20-minute blocks, each block consists of five segments, with each segment comprising a three-minute sub-threshold effort, followed by a one-minute VO2max burst; promptly return to sub-threshold. Repeat.
Why do this workout?
Sustained by not steady training: Even time trialists can benefit from training their ability to respond and recover. Try doing "over-unders", alternating between efforts just above and below threshold.
