Ercolina workout. Warm up. One minute interval on, one minute recovery. Repeat 10 times. Cool down.
The heart rate graph shows this was done effectively. In the later intervals, I hit the mark of having just recovered enough at the start and peaking just at threshold for the end. After a session I like this, my arms and shoulders feel puffy and swollen and the floor is covered with the sweat that drips from my head.