May 12, 2020
Technical Tuesday Vol.7
Streamline & Bodyline
The first technique all GSC swimmers learn is the streamline (underwater) and bodyline (on surface). Our goal is efficiency in the water. Without a proper streamline or bodyline, the swimmer will create unnecessary resistance thus using more energy to swim via drag. The swimmer can effectively utilize the 5th stroke or pullout with a perfect streamline. Technically, there are three drag forces; friction drag due to the viscosity of water, pressure drag due to the complex shape of the human body, and wave drag created at the surface of the water. In understanding streamline and bodyline, lets start from the top…literally.
Hand Position – Prone Streamline
The first body part that causes friction against the water are the swimmers’ hands. If they are not tightly together or angled in the proper position, more friction will be produced. “Hand over hand & wrist over wrist” is the best technique to be the most hydrodynamic.
Head position - Prone Streamline
Next, and as important, is the head position. Below are three streamline patterns of the three head positions. Note how the flow of water around the swimmer’s neck, chin, and hips. The more the water recirculates around the swimmer’s neck, chin, and hips, the more resistance is created. There are three head positions; above arms, aligned with arms and chin tucked in.
Studies have shown that the position of the head aligned with the body (position 2) is the one that offers less force drag in comparison with positions with head lowered or lifted up.
Hips and Legs – Prone Streamline
To further maintain the perfect streamline, the swimmer’s core should be tight and legs are required to be “locked” together. Feet and toes need to be pointed and together as well. Any gap between the legs or feet will result in drag.
Streamline on the back is the same concept as in the prone position.
As the swimmer breakouts from the streamline position to the surface of the water, it is now important to maintain proper bodyline. All strokes require the knowledge and ability to have a mastery of the bodyline. In today’s TT, the discussion will be focus on the bodyline of freestyle and backstroke.
The goal of a perfect bodyline is for the body to be as narrow as possible. During free or back, hands entering water will create drag. (the discussion of this will be in future TTs). The focus today will be the body position on the surface of the water.
Dryback & Dryhips (Drystomach)
GSC uses the terms “dryback” and “dryhips” to help the swimmers visualize being “on top” of the water for free and back, respectively. Could a swimmer actually achieve dryback and dryhips? No, but if he/she understands the concept, he/she is on the way to understanding and performing a perfect bodyline while swimming. Another aspect of the bodyline which might cause confusion but is a necessary concept to understand is the ability to press chest “down” (free) and upper back “down” (back). This needs to be performed while still maintaining a dryback and dryhips. This effect can be thought of as “downhill swimming” (more in future TTs).
“Dryhips” / Drystomach”