Originally Posted by
Gav888
8 x 5 minute intervals with 2 minutes rest between each interval = 40 minutes at threshold
2 x 20 minute intervals with 10 minutes rest between each interval = 40 minutes at theshold
The former set is easier than the latter. Increase the power during the 5 min interval by 6-8% and shorten the rest to 1min and they get closer.