Running is just crap. Unless you are like my mate who is a fell runner and you can't MTB as fast as him. He did ride for many years, I used to pick him up as a youngster to go to races, he wasn't that fast but kept at it. He was just a bit too 'slim' - roll on 30 years, and he's a shoot hot fell runner as a vet in his 50's. I said, with your times, get back into bikes, he said, bikes need to come down in price - yes, they are stupid money now.
Cycling is me, despite some massive life changing injuries (and managing family response) - my family don't do now't, boring.
My mum was worried I was walking up Snowdon a few weeks ago.. WTH, it's a hill - slightly complicated by a knackered knee, but she didn't know..
I don't take un-necesary risks, because I have a job to turn up to.