Originally Posted by 12strings

I started doing this 30-second interval session on a trainer in the garage once or twice a week, and while it's super hard, it's only 20 mins total...it really works...I noticed immediate gains in strength, fitnes, climbing, top speed, endurance....everything...after only a week or two of doing these. It let me keep up with riders who were riding double and triple the amount I was doing.

https://www.youtube.com/watch?v=08f0qFwtuf0