The butterfly is a difficult swimming stroke to master; it requires synchronization between two main parts of your body, your arms and legs. A strong dolphin kick and the strength of your upper body are required to propel and pull your body through the water in an undulating manner. If either part of your stroke is weak, the best exercises you can perform are those that can help strengthen and improve in the area needing attention.
Position Kick Exercise
The dolphin kick is a whip-like movement of the body from the chest to the toes. Your legs are held together and move up and down simultaneously. One of the best exercises for strengthening and perfecting your kicking technique is to swim several lengths of a pool in different positions without the arm movement. Practice the kick by swimming one length of the pool with your arms extended above you head, hands together and head below the surface of the water. With your arms in the same position, repeat the exercise on your right side, on your back and then on your left side. Swim fins can be used to reduce the intensity of the exercise.
Vertical Kick Exercise
For a more balanced dolphin kick, Katie Arnold, USA Swimming National Team coach fellow, recommends performing the vertical dolphin kick exercise. Start in deep water, cross your arms across your chest and practice quick, fast up-and-down kicks to keep your head above the water. Your body remains vertical with no forward or backward movement. Arnold recommends performing the exercise for 30 seconds followed by a 30-second rest. As your technique becomes perfected, lift your hands out of the water, keep your elbows bent below the water and repeat the exercise for 20 seconds. Bob Bowman, coach of the North Baltimore Aquatic Club, recommends that advanced swimmers use weights while performing this exercise; it helps to build strength, kicking speed and power.
Practice the pull-and-push motion of your arms without the kick. You will need a pull buoy for the exercise. This is a foam devise you hold between your thighs to keep your legs up as you swim. The pull part of the arm movement is when your arms reach forward into the water, move out toward the sides, catch the water and pull the water downward in a semicircle fashion toward the center of your body. The push part of the stroke is when your palms push the water back from under to alongside your body. Concentrate on only the pull and push of the stroke and perform this exercise for four lengths of the pool. Rest and repeat.
Arm strength can improve by focusing on one arm at a time. You will need to use a kickboard and a pair of fins for this exercise. Start the exercise face down in the water with both hands holding the kickboard at arm's length. Release the board with your right arm, exhale and practice the pull-and-push movement of your arm. During the push part of the stroke lift your head to take a breath and kick. Return your arm out in front of your head to start the next right-arm stroke. Perform the stroke for 50 yards, rest and repeat with the left arm. To make the exercise more difficult, do not use a kickboard; just keep the stationary arm straight in front of your body. If you are having breathing difficulties, wear a mask and snorkel.