GC is definitely no monkeying around

It's your workout in 12 minutes. The first four are warm-up. The second 4 minutes are all out sprints of 20 seconds followed by 20 seconds of recovery. The last 4 minutes are cool down. It's a program that was created by one of the contributors of Muscle Media Magazine - you can read a little about it here.

The complete workout is included in the special training issue of MM that was available back in April (if you can find a copy it's worth it's weight in gold). In order of difficulty the workouts are rated (easiest to hardest) 20 MAS, HIIT then GC.

HTH
Nat