And attitudes like yours bug me, I'm all for the, 'footballers are overpaid dickheads' view because on the whole its true.
But what you cannot underestimate is how physically fit they have to be, my best mate plays in League 1, just breaking through, and he's ridiculously fit, but he's still nowhere near fittest in the squad and if you compare a league 1 game to the premier league the difference is huge.
This kid is 19 and clearly not fully developed, you need to cut him some slack.
The fact that you think a 90 minute run is all it is, says it all to me. Have you ever played a game of football? If you have then imagine it 100 times faster, you can't understand it.