MIAMI, June 17 : Players arriving in Miami for World Cup matches may find themselves battling more than just opposing teams, as sweltering heat and humidity threaten to turn the tournament into a test of endurance as much as skill. Teams from cooler climates face particular risks if they have not had time to acclimatise to Miami's punishing conditions, warned Dr Jason Kostrna, an assistant professor and graduate kinesiology program leader at Florida International University. Kinesiology is the