50k doesn't sound so bad....as long as you don't do the math.

I have run the 10 Mile Trail Challenge at Salt Fork State Park several times.  It is a fun and hilly trail run.  The Bigfoot is three loops of the same trail.  I knew about Bigfoot but always questioned the sanity of those wanting to run three loops.  One is hard enough.  But here I was running three loops that would provide me of 4,500 feet elevation gain and almost 7 hours of "fun".

The first two laps felt pretty good.  I was fueling up and keeping a nice steady pace.  The third lap started to wear on me as the energy in my legs just wasn't there.  I wasn't to full bonk yet but a fourth lap would have done me in. 

So I did 50k....or 31 miles.  Not sure if I will go back to long distance trail running like this again but it was nice to do it.