Huh? The last time the U.S. sent a full-strength team (1999), we dominated Pan Am Juniors sprints. In 2001, we didn't send a full-strength team due to 9-11. Can't speak for the distance runners, but most of the junior sprinters also do club track. Thus, they are VERY accustomed to running in the summertime. In fact, some run faster in the summer than they do during the school season. Not to mention that the Jamaican school season ends even earlier than the U.S. one.