Eh I would disagree with midfielders doing 'less running'. Based on the (admittedly few) articles I've read, it's not uncommon for them to run anywhere from 4-8 miles in a single game, and they do have to help both offensively and defensively. I've been to tons of games and the midfielders never stopped moving.  Then again, it's not like there's an easy position in soccer, and I totally agree that playing full-back is extremely strenuous. Let's focus on what's really important, and that's how much this fat sack of shit sucks.