In late 1933, Henry Myers swam a butterfly stroke in competition at the Brooklyn Central YMCA. The butterfly style evolved from the breaststroke. David Armbruster, swimming coach at the University of Iowa, researched the breaststroke, especially considering the problem of drag due to the underwater recovery. In 1934 Armbruster refined a method to bring the arms forward over the water in a breaststroke. He called this style "butterfly". While the butterfly was difficult, it brought a great improvement in speed. One year later, in 1935, Jack Sieg, a swimmer also from the University of Iowa, developed a kick technique involving swimming on his side and beating his legs in unison, similar to a fish tail, and then modified the technique afterward to swim it face down. He called this style "Dolphin fishtail kick". Armbruster and Sieg quickly found that combining these techniques created a very fast swimming style consisting of butterfly arms with two dolphin kicks per cycle. Richard Rhodes claims that Volney Wilson invented the 'Dolphin' after studying fish, and used it to win the 1938 US Olympic Trials, earning him a disqualification.