This is Synchronized Swimming (1958, Helen M. Cardan)

16mm. film found in Chicago Film Archives Chicago Public Library Collection 1950s instructional film that demonstrates the basic strokes used in synchronized swimming and such routines as dolphin, porpoise, somersaults, corkscrew, water wheel, ballet leg, shark, front flip, bent knee and front and back walkover. Produced and created by Helen M. Carden; Directed by Richard Kahn