I've never been much of a runner. Fast sprinter but that's not much good. Put me on a road bike though and I'll go for miles. I do like the crosstrainer too. Both are far less impact on my knees. They're not totally shot but I've spent a lot of my working life on my knees withour kneepads so I'm bound to have done some damage.
Loving that avatar pic Charlotte, I like the purple ribbed top, you really suit that colour.