Myth #5. The reason we pull freestyle underwater with a high elbow is to increase the surface area of our arm.
Forgive me. In case you hadn't noticed that I am preaching high elbows a lot, there is a reason. At the end of each camp at the Race Club I always end by prioritizing the 10 or so points that I make to improve speed and efficiency. The top three are 1) High elbow 2) High elbow and 3) High elbow. Dropping the elbow is like taking a drag suit into competition...only worse, because you don't feel or see what is happening to you...until your tongue is hanging out.
So when I ask campers and coaches, why the high elbow, I usually get increased power or increased surface area. I don't think either one is right.
We all know from throwing on a pair of hand paddles (which, by the way, my coach Flip Darr, reinvented in 1967...Ben Franklin was the first to use, I believe) we get a surge of power from the added surface area. So by creating EVF, do we also increase the surface area of our pulling arm?
First, the only area that matters is the part of the arm that ends up creating propulsive drag, which is the hand and forearm, so we can forget about the upper arm for this argument. Now the question is do we have more surface area of the hand/forearm in the EVF position than we do in the deep arm/elbow position?
We are really talking about the surface area projected onto a plane perpendicular to our long axis, which is the area creating the propulsive force in the backward direction. In theory, one could argue that a poor swimmer leads so much more with the elbow in the dropped position (the hand/forearm creates a forward angle at the elbow joint) that the surface area is reduced.
But with reasonable swimmers that is not what you see. From head on or from the rear, you don't see much difference in the surface area of the forearm/hand regardless of whether it is in the dropped position or the EVF position. The surface area of the arm remains the same.
Therefore, I rest my case. The reason we like the EVF position is to reduce drag....and drag remains the #1 enemy of the swimmer.
Gary Sr.
Parents
Former Member
From head on or from the rear, you don't see much difference in the surface area of the forearm/hand regardless of whether it is in the dropped position or the EVF position. The surface area of the arm remains the same.
I think what we need here is one of Connie's computer generated swimmer pictures. One showing a dropped elbow and one showing a high elbow. The effective surface area of the forearm most certainly does not stay the same.
With a completely dropped elbow (the forearm is parallel to the direction of movement) the effective surface area is near zero, the forearm is hidden behind the elbow when viewed from the rear. When the forearm is perpendicular to the water it has an effective area of its length times it's average diameter.
Consider swimming breaststroke with a style where the arms are recovered completely under the water. It works because when you are pulling you are keeping your arms perpendicular and therefore pressing on the water with a large surface area, and you recover the hands with the forearms parallel to the direction of travel so that the surface area is minimal.
Forces in fluids are isotropic, meaning a particle of water will exert equal force in all directions. If you unbalance the forces the fluid will flow. So you have to think of forces in water as pressure, e.g. pounds per square inch (psi). If you double the area you double the force.
Another way to look at it is that all pressure forces exerted by a fluid (i.e. forces other than surface drag) on a solid object will be perpendicular to the surface of the object. So if your forearm is at 45 degrees to the direction of travel, even if you pull it straight back while maintaining the 45 degree orientation, the force of the water on the forearm will still be at ninety degrees to the forearm, i.e. 45 degrees to the direction of movement. This means that exactly half the force you are using to move the arm is directed sideways, perpendicular to the direction of travel, i.e. you are wasting half the energy you are expending. So, from an efficiency point of view, it makes a lot of sense to have your arm perpendicular to the direction of travel so as to maximize the portion of the energy you are expending that is pushing you forward instead of moving water sideways.
Edit: I've added two screen shots of Mr. Smooth, in the front view you can see that his forearm has a large effective area relative to his right forearm. I realize that the right arm is in recovery but it does demonstrate the reduced area when the arm is pointing mostly forward.
From head on or from the rear, you don't see much difference in the surface area of the forearm/hand regardless of whether it is in the dropped position or the EVF position. The surface area of the arm remains the same.
I think what we need here is one of Connie's computer generated swimmer pictures. One showing a dropped elbow and one showing a high elbow. The effective surface area of the forearm most certainly does not stay the same.
With a completely dropped elbow (the forearm is parallel to the direction of movement) the effective surface area is near zero, the forearm is hidden behind the elbow when viewed from the rear. When the forearm is perpendicular to the water it has an effective area of its length times it's average diameter.
Consider swimming breaststroke with a style where the arms are recovered completely under the water. It works because when you are pulling you are keeping your arms perpendicular and therefore pressing on the water with a large surface area, and you recover the hands with the forearms parallel to the direction of travel so that the surface area is minimal.
Forces in fluids are isotropic, meaning a particle of water will exert equal force in all directions. If you unbalance the forces the fluid will flow. So you have to think of forces in water as pressure, e.g. pounds per square inch (psi). If you double the area you double the force.
Another way to look at it is that all pressure forces exerted by a fluid (i.e. forces other than surface drag) on a solid object will be perpendicular to the surface of the object. So if your forearm is at 45 degrees to the direction of travel, even if you pull it straight back while maintaining the 45 degree orientation, the force of the water on the forearm will still be at ninety degrees to the forearm, i.e. 45 degrees to the direction of movement. This means that exactly half the force you are using to move the arm is directed sideways, perpendicular to the direction of travel, i.e. you are wasting half the energy you are expending. So, from an efficiency point of view, it makes a lot of sense to have your arm perpendicular to the direction of travel so as to maximize the portion of the energy you are expending that is pushing you forward instead of moving water sideways.
Edit: I've added two screen shots of Mr. Smooth, in the front view you can see that his forearm has a large effective area relative to his right forearm. I realize that the right arm is in recovery but it does demonstrate the reduced area when the arm is pointing mostly forward.
