At World Cups past and present, team spats show egos as well as muscles need massaging

Cameroon national team players arrive at the Galeao Air Base in Rio de Janeiro, Brazil, Monday, June 9, 2014. Cameroon's World Cup team refused to board a plane due to take them to Brazil on Sunday because of a long-running dispute over bonus payments for the tournament, forcing their national federation to take out a loan to meet their demands. (AP Photo/Rodrigo Abd) (The Associated Press)

Chelsea’s player Samuel Eto’o leaves the aircraft as Cameroon’s national team at the Galeao Air Base in Rio de Janeiro, Brazil, Monday, June 9, 2014. Cameroon's World Cup team refused to board a plane due to take them to Brazil on Sunday because of a long-running dispute over bonus payments for the tournament, forcing their national federation to take out a loan to meet their demands. (AP Photo/Rodrigo Abd) (The Associated Press)

The World Cup hasn't even begun and already there's been a training ground run-in between two Dutch players and Cameroon's entire team delayed its flight to Brazil in a dispute over their tournament bonus.

Prodigious talent often goes hand-in-hand with oversized egos and managing them can be a full time job for team leaders in the pressure-cooker environment of the sport's showcase event.

Sometimes, players' feelings need as much massaging as their calf muscles.

"Conflict is inevitable," sports psychologist Bradley Busch of London-based mental skills training company Inner Drive said Monday. "It is what the team then does with it that is important."