Now I know not to trust my body

I started running around 15 years ago.  Over that time, I've been reasonably consistent.  The only major gaps in were periods where I was recovering from some type of injury.  Generally, I've always followed the advice of listening to my body.  The only significant injury I've had was due to pushing past pain in my ankle. (No one tell Emily I'm admitting that.)

Yesterday I learned that my body isn't all that trustworthy.  I did a twelve miler along the canals in Mons.  It's a nice, flat route.  The weather was perfect.  (And I mean perfect by normal standards, not the ridiculously low standards I have for weather in Belgium).  Emily & I are running a half marathon in The Hague next month.  I can finish a half without training, but I'm throwing a few long runs in to get my pacing set.  I held an easy pace for the first 8 miles.  Somewhere between 8-9, my pace began creeping up.  By mile 9, I was 30-45 seconds faster per mile than I had planned to run.  My legs felt good.  My heart rate was good.  I decided to go with it because I was feeling good and only had 3 miles to go.

Then comes the last mile.  The heart rate is still ok.  The legs hurt.  They aren't fatigued.  They hurt.  The pace drops back to the original, easy pace.  My legs still hurt.  I finish the last half mile at a walk.  Had I been running the half, I would have pushed through.  Since it was a training run, I know i have to get my mileage back up.  (The last month really has been limited to treadmills or cross training.)