I've been running for a couple of years now and I've noticed a constant in my training...
Sometimes I don't feel my best and my pace suffers, or I cut a long run short.
Sometimes I feel pretty good and I decide halfway into my run, to add another mile or to tempo the last mile and speed things up.
Sometimes I run 3 miles, sometimes I'll run 9. (I'm still trying to work my way up to 13.1)
The constant is simply this:
When I commit to a distance, no matter how fast or slow I go, no matter how far I run, as soon as I get half a mile from my finish, I mentally shut down and I feel every ache and pain in my body. I get exhausted. I find myself glancing at my GPS every 2 seconds. I get thirsty beyond the capacity of my bottles.
In short, that last half mile kills me.
It's the hardest 5/10ths of my life.
Why is that?