Comment by jeffbee

It's interesting that they characterize a 30-second cycling effort as "all-out" when any cyclist knows it's impossible to go "all-out" for that long. You can go really all-out for a few seconds before your whole metabolic process needs to switch modes. A 30-second effort has to be paced. "All-out" intervals are very effective but for me they mean 4 seconds out of every 30 seconds.