Understanding overunder intervals

Question

I'm reading The Time Crunched Cyclist and trying to work out a training plan for a century later on this year. I am having a really simple problem understanding the overunder (OU) interval shorthand. For a ride listed as:

90 min. EM with 3 x 12 min. OU (2U, 1O) (8 min. RBI)

What does the (2U, 1O) designation for the OU interval refer to?

I know I'm supposed to do 3 repetitions of 12 min. at some pace with 8 minutes in between. But what is that timing/pace -- how long under and how long over? I can't seem to find it explained anywhere in the text.

Answer 1

I had a difficult time understanding this too. the 2U, 1O stands for 2 minutes under your threshold, and 1 minute OVER your threshold. (that's a capital letter O, not a zero, which threw me for a long time).

Answer 2

You are right that it's 3 intervals of 12 minutes with 8 minutes recovery between them.

The over and under refers to your SteadyState rate with is specific to the book, but based aerobic and lactate threshold rates - to get the heart rates right you should either take a MaxVO2 test or do the tests in the book

In your example you within your three intervals you do 2 minutes at the upper end of your aerobic heart rate (the SteadyState intervals) and then one at or near your lactate threshold rate (the ClimbingRepeat rate in the book). Then repeat, so that in your 12 minute interval you get 4 'over' surges.

In terms of perceived effort, that would be 2 minutes about a 7 on a scale of 1-10 and then 1 minute at a scale of 8-9.