result of the differences between the Spanish and English leagues, but he insists they are actually pretty similar.
"Football-wise there are not too many differences. The style is not too dissimilar although it is maybe slightly more aggressive in this country," he adds.
"People are aware I have been trying to gain a little bit of weight in terms of muscle, maybe an odd kilo to bulk up a little bit. But the concentration levels are the same.
"You can't let your concentration levels drop for a second. So football-wise it is not so different."
David was talking to ManUtd.com and PA Sport.