Ok, over the course of the holidays I have to do my PE coursework; which is a six week personal exercise plan. We make it all up ourselves, and we can do whatever exercises we choose, as long as they'll help improve cardiovascular endurance.
The thing is, running would be the most convenient activity to include, but I can't run for very long without my knees and shins starting to play up and as a result it tends to be a bit of a waste of time, because the duration of time I run for probably won't have any effect whatsoever as it's so small.
Cycling I find much kinder on my joints, but I'm not sure as to how it ranks in comparison to running. I could cycle for an hour or more each day without very much difficulty, but I definitely can't run non-stop for that long.
So how to running and cycling compare with regards to their effect on general cardiovascular endurance?