The back dive requires a depth of at least five to six feet. The toes should be well up to the edge of the pool and the back well hollowed. This is the main essential; one also must point the toes out well. This is a very difficult dive and requires plenty of nerve and practise.
The "jack-knife dive" is made from the back-diving position by springing up in the air, doubling the body up from the waist, and throwing the legs up behind, trying to enter the water as clean as possible facing the springboard.
The "dolphin dive" is the straight front dive, only the body must be turned sharply in the air from front to back. The easiest way is to practise this from a springboard about six feet above water.
The back somersault from the springboard requires the swimmer to double up while in the air; the arms should be lowered from the shoulder and bent up from the elbow, and the knees drawn up, so as to make the body ball-shaped, when the turn-over can be made easier.
The front somersault is exactly the same, only with the face forward instead of backward.
THE DOLPHIN DIVE