Muscle Groups used in Swimming Strokes

This is a great video to view the muscle groups involved in different swimming strokes.  There are two things that jump out at me right away: 1- Breaststroke….check out the "chain" of events as the athlete takes the stroke.  The muscles are not all used at the same time but instead run from the hands/arms to the back to the legs, and back to the hand/arms.  2- Backstroke and Freestlye…..look at the legs and the difference between the two strokes.  This is why to properly train freestyle, you've got to kick "on the front", and to properly train backstroke you've got to kick on your back.