The up-kick of dolphin kick on your back helps keep you underwater.
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Swimmers use underwater dolphin kicks to maintain momentum after coming off the block or out of a turn, helping them maintain the speed needed to pull ahead of the competition. A mere fraction of a second can mean the difference between first and second place in competition, but perfecting this underwater kicking technique can improve starts and can help a swimmer take -- and keep -- the lead in a race.
The underwater dolphin kick, according to Corey Binns in the 2008 Popular Science article, вЂњHow It Works: The Dolphin Kick,вЂќ propels swimmers through the water faster than any stroke done at the water's surface. Surface resistance can slow down the glide after pushing off the wall, but a combination of a streamlined body position and strong kicks that start in the core and work their way to the toes in a whip-like motion -- executed while the entire body is underwater where there is less resistance -- help swimmers maintain the momentum they get diving off the block or coming out of a turn. Streamlining and maintaining a good body position and balance while underwater, USA Swimming says, will help reduce resistance and make kicking more effective.
Streamlining is the gliding position a swimmer's body takes after diving off the blocks or coming off the wall out of a turn. In streamline position a swimmer's arms are overhead, arms straight and keeping hand over hand with upper arms hugging the ears. The core is tight, legs are straight and the swimmer is horizontal in the water. Kicking in the streamline position is faster than any stroke done at the surface of the water, but the streamline position must be maintained to avoid resistance. Poor position in the water can be overcome with a stronger kick, but a strong kick is better used to power speed rather than compensate for poor body position.
The dolphin kick used in the streamline position after starts and turns begins in the core to stabilize the kick that is powered by the quads. Knees bend to set up the kick with legs following through into a complete extension, whipping to finish the kick in the front of the body. Minimizing hip movement, USA Swimming says, to move the body forward rather than up and down. Too much hip movement keeps the legs from doing their job of "catching" the water when whipping to propel the swimmer forward.
Starts and Turns
Starts and turns can mean the difference in winning a race, USA Swimming says, adding that swimmers need to be their best, not just in their stroke, but also coming off the block or the wall. For underwater kicking to be effective, momentum needs to be set up by a strong push off the block or wall into the streamlined position. To improve and maintain good starts and turns, they need to be practiced on a regular basis as part of your workout.