A while back, I jumped on the triathlon website Slowtwitch and got attacked for saying that the power in the freestyle pull comes in the front of the stroke (hand entry to shoulder), not in the middle (shoulder to belly button) or back (belly button to release). Nonsense...they said. Didn't you read the article by Popov's coach showing the power is at the end of the stroke?
That never made sense to me. After all, at the end of the stroke there is only about one muscle still working, the tricep, and the hand is not in that position for very long.
At last, I got the proof I needed. A few weeks ago I was tested on the Velocity Meter, a very cool device that measures the speed of the body through the entire stroke cycle. It was VERY revealing and provided tons of information I could not get elsewhere.
Such as:1) the body speed slows by as much as 40% from the fastest to the slowest point during a single arm stroke. 40%!!! That is huge. The difference in speed is directly caused by the body going from a relative streamlined position to a very non-streamlined position and back again.
2) The fastest point in the stroke cycle is when the hand first enters the water and the slowest point is when the hand is about at the shoulder underwater. That is when the upper arm is pointing nearly perpendicular to the line of the body (ie most drag).
I realize that the speed of the body at any given instant is a result of the propulsive power minus the drag forces, that one cannot determine just from the velocity that the power is really greater in front. But when the speed drops from 2.5 meters per second when the hand is in front to 1.4 meters per second when it is in the middle, I have to believe that the power in front is greatest.
By the way, the propulsive power of the arm is created by both lift forces at the beginning and drag forces in the middle, as the hand shifts from forward motion to backward motion (then forward again as it releases).
Anyway, read my latest blog on our website www.theraceclub.com to find out more revealing secrets from the Velocity Meter.
Gary Sr.
Parents
Former Member
The power forces of the hand change from almost pure lift in the outstretched position, to nearly pure propulsive drag when the hand is about at the shoulder level. The motion of the hand is in nearly a perfect circle of about 2 feet. It moves forward, down, then back, up and forward again, leaving almost exactly where it started. In between these points at the top of the circle (pure lift, moving forward) and the bottom (pure drag, moving backward), there are vectors of force for both lift and propulsion occurring simultaneously. Lift likely has the effect of increasing our velocity by reducing drag, if we have any significant propulsion with our legs. It turns out, understandably, that the best hold-out-in-front, lift swimmers have the best kicks (Thorpe, Phelps, Hackett, Lezak etc). Out front, they are generating lift not just from the hand, but from the entire arm. Also, the more speed they can generate while holding out in front, the more lift...just like a plane taking off down the runway.
Gary Sr.
The power forces of the hand change from almost pure lift in the outstretched position, to nearly pure propulsive drag when the hand is about at the shoulder level. The motion of the hand is in nearly a perfect circle of about 2 feet. It moves forward, down, then back, up and forward again, leaving almost exactly where it started. In between these points at the top of the circle (pure lift, moving forward) and the bottom (pure drag, moving backward), there are vectors of force for both lift and propulsion occurring simultaneously. Lift likely has the effect of increasing our velocity by reducing drag, if we have any significant propulsion with our legs. It turns out, understandably, that the best hold-out-in-front, lift swimmers have the best kicks (Thorpe, Phelps, Hackett, Lezak etc). Out front, they are generating lift not just from the hand, but from the entire arm. Also, the more speed they can generate while holding out in front, the more lift...just like a plane taking off down the runway.
Gary Sr.
