Christiano Ronaldo, who plays for Portugal and Spanish football club Real Madrid says the noise disturbs the players' concentration.

VOA: standard.2010.06.14

Christiano Ronaldo outscored Lionel Messi by nine goals in La Liga last year, and Real Madrid went on to score 102 goals as a team.

FORBES: Should Feats Of Messi, Ronaldo Get An Asterisk Due To La Liga's Economic Disparities?

Just ask soccer players David Beckham and Christiano Ronaldo, or American sports stars like Tiger, Kobe, Jeter, and Wade, or tennis stars like Roger Federer and Rafa Nadal.

FORBES: Selling Sex In Sports Creates Opportunities But Demands Responsibility