One of my favourite conditioning exercises is doing intervals on my exercise bike but I'm a bit confused as to how to arrange the intervals themselves. Some online resources say sprint for 30 seconds, rest for 30 seconds. Others say 20/30, 10/30, etc. etc.
Currently I use a 30:30 protocol and then when I start to fatigue I go to 20:30 and sometimes will finish with 10:30 intervals finishing at around 12-15 minutes total.
IS this approach effective or should I just stick with one work:rest ratio per session? Obviously I would last a lot longer doing a 10:30 session than I would a 30:30 session so the work:rest ratio would dictate the total session time. Currently I could probably only last 5 or 6 minutes using a 30:30 ratio exlusively, I change the ratio to increase my workout time.
One other question. As I fatigue, my RPM's lower dramatically towards the end of each sprint, should I keep pedalling despite the low power output or should I terminate the set?