To prepare for last month's World Cup, the American and English squads took two different paths toward acclimating to South Africa's higher altitude. The English players spent two weeks training in the Austrian Alps, but the Americans chose to not sacrifice the practice time needed to adjust their bodies to the elevation of the tournament.
Because both teams lost and were sent home at the same point in the tournament, it's hard to say which approach was better. But now, new research from Oxford University suggests that an approach somewhere in the middle may be best.