Jürgen Klinsmann understands what it takes to compete in a World Cup.  With eleven goals for the German national team across the 1990, 1994 and 1998 tournaments, he is still the sixth leading goalscorer in World Cup history. 

As he prepares the U.S. men’s national team for this year’s trip to Brazil, his message of preparation begins with world-class fitness.  Now, a new research review from three sports scientists confirms Klinsmann’s obsession with being in top condition.