Great shots… I especially love the first two (trail runners in the landscape). Third and fourth give an idea of how exhausting it is although they manage to smile for the photographer I agree with you about those runners, they are real beasts.
50 miles and up and down! wow.. you those runners in the Alps too... I once made it tot the top of the mont Ventoux on a bicycle to find out i was only a bit faster than runners doing the same thing ( 1500m up and 21 km)congratulations with getting the smile of those runners... ( or did you use a fake finish line)