This is a sprint drill that takes about 3-4 minutes if you need a quick filler.
Ten seconds on, sprinting (RPM 110, gear as hard as you can get it and still (barely) maintain 110) ten seconds off, resting. Repeat ten times... yikes!
The rest can either be a total rest down to a flush/rest gear or just slowing down and keeping the gear. That is pretty advanced stuff, don't throw that on just anyone :)