Ian Crocker dives in at the start of the semifinals of the 100m butterfly at Trials. (Al Bello/Getty Images)  Swimmers, note the locked and straight elbows, the arms squeezing tight to the head, the pointed toes, and the feet together--you can tell he's about to pierce the water just like an arrow, with barely a splash.

Watch as Katrina enters the water for her 100 Individual Medley at the Straehle Individual Championship meet during the summer