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 beginning of every competitive stroke only starts the production of power or inertia. Drag forces in conjunction with lift forces (the hand moving into stable water) are the most potent producers of power and occur later in the stroke. The first quadrant of any stroke merely sets the wheels in motion (setting-up the stroke), so peak drag and lift forces can take place during the transition from the first quadrant and into the second quadrant of each competitive stroke. The hand entry and beginning of the stroke does not produce any significant power but is critical in establishing peak efficiency as the hand and forearm become vertical. The power that is produced during the end of the first quadrant and through the start of the second quadrant is where peak power (torque) is produced. The end of the second quadrant of the stroke where the arm extends (and away from the body) can help maintain the power gained through the power phase. There is a lot of research done at the Olympic Training Camp Biomechanics’ Facility showing that peak power is produced during the transition from the 1st and into the second quadrant (another spike comes at the end of the stroke when the hand tends to accelerate (this maybe one reason it seems power is generated at the beginning of the stroke).
The beginning of every competitive stroke only starts the production of power or inertia. Drag forces in conjunction with lift forces (the hand moving into stable water) are the most potent producers of power and occur later in the stroke. The first quadrant of any stroke merely sets the wheels in motion (setting-up the stroke), so peak drag and lift forces can take place during the transition from the first quadrant and into the second quadrant of each competitive stroke. The hand entry and beginning of the stroke does not produce any significant power but is critical in establishing peak efficiency as the hand and forearm become vertical. The power that is produced during the end of the first quadrant and through the start of the second quadrant is where peak power (torque) is produced. The end of the second quadrant of the stroke where the arm extends (and away from the body) can help maintain the power gained through the power phase. There is a lot of research done at the Olympic Training Camp Biomechanics’ Facility showing that peak power is produced during the transition from the 1st and into the second quadrant (another spike comes at the end of the stroke when the hand tends to accelerate (this maybe one reason it seems power is generated at the beginning of the stroke).
