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.
... 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).
...
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 have not seen the data you are looking at, so keep in mind that I'm floating a theory. You'll have to decide if it matches up with what you are seeing.
What you point out is still consistent with the power coming from middle or back part of the stroke.
A) The fastest point is when the hand first enters the water... That might be due to what the other hand is doing, which will be in the middle or back part of the stroke (depending if the person is more catch-up or more windmill).
B) The slowest point is when the hand is about at the shoulder... That implies that the swimmer is slowing down from hand entry to middle part of the stroke. This might suggest that the front part of the stroke is not where the power is. (At the very least, that position is not favorable for muscle leverage.)
What might be interesting is if you did the same swims with only one-arm and a pull-buoy (no kicking), to try to isolate what is happening during the stroke. It would be tough to make it close enough to a normal stroke (for comparison), but it would take some of the other variables (like the other arm pulling) out of the equation.
... 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).
...
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 have not seen the data you are looking at, so keep in mind that I'm floating a theory. You'll have to decide if it matches up with what you are seeing.
What you point out is still consistent with the power coming from middle or back part of the stroke.
A) The fastest point is when the hand first enters the water... That might be due to what the other hand is doing, which will be in the middle or back part of the stroke (depending if the person is more catch-up or more windmill).
B) The slowest point is when the hand is about at the shoulder... That implies that the swimmer is slowing down from hand entry to middle part of the stroke. This might suggest that the front part of the stroke is not where the power is. (At the very least, that position is not favorable for muscle leverage.)
What might be interesting is if you did the same swims with only one-arm and a pull-buoy (no kicking), to try to isolate what is happening during the stroke. It would be tough to make it close enough to a normal stroke (for comparison), but it would take some of the other variables (like the other arm pulling) out of the equation.
