In reply to wildirishman:
> I have always run and run comfortably, on roads, on trails, on mountains, on anything.
How long have you been running? I heard that a lot of people who have been running since their teens burn out by late 30s. I'm nudging 40 and only took up running in the last 4-5 years so am hoping if I take it easy I'll have another decade or two in me.
Maybe take a break and do something different for a few weeks. I often plateau with training and during the summer when miles are long and the calendar is full I tend to struggle more with motivation.
I'm XC skiing at the moment - its a nice workout, cross training and I'm just enjoying the scenery rather than trying to push any numbers. When the snow clears I'll get back into running more seriously, but will be refreshed and up for the challenge.