The Hammers took the opportunity to get away for some warm-weather work ahead of their Barclays Premier League clash with Tottenham next Monday.
McDonald confirmed the trip was all about hard work as they look to replicate the effects of a similar excursion during last season.
"It's never a reward," he told the club's official website. "Unless it is something like an end-of-season trip after getting promoted or staying in the Premier League. That would be classed as a reward, but this trip was part of our training regime.
"We did a similar trip last year and we got positive results. We might not get the result we want straight away, but it is certain over the coming weeks that the players will up their game, their energy levels and the distances they cover."