I had to go out anyway, to run an errand of sorts, so I decided to take the bike and make a short ride out of it.  Five miles later, I’m home and I don’t ache (well, not much and not as acutely as I do after running – this is muscles protesting, not joints protesting.  Muscles sort themselves out, more or less).  Not a breeze of a ride (too many hills around here) and I was overtaken by one cyclist who was clearly drifting along merrily where I was working up a hill (ok, slight incline).  And the fast bit where I cranked up the gears and just went for it was a blast.