Running

I was thinking this on Saturday!
Now my knees arnt killing me, a decent 40 minute run feels as good as a 2 hour session on the track. And without the hour each way ride there; time and space reductions too!
This may well be my winter fitness training of choice this year.

Only problem is I prefer 5 hours of suffering in miserable weather to not being able to walk down stairs after a 30min run. :)