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.
Chris: if you agree that distance per stroke = speed divided by stroke rate, then at 34 strokes for 50 meters, we don't have the same DPS or the same SR. The DPS and the SR are below:
Lezak: 50 meters in 23 seconds = 2.17 meters per second
34 strokes in 23 seconds = 1 stroke every .67 seconds
MJM: 50 meters in 35 seconds = 1.42 meters per second
34 strokes in 35 seconds = 1 stroke every 1.02 seconds
Lezak: 2.17 meters per sec./.67 strokes per second. DPS = 3.23 meters
MJM: 1.42 meters per sec./1.02 strokes per second. DPS = 1.39 meters
So I should have said Lezak and I can take the same number of strokes for 50 meters. However, his stroke rate combined with his distance per stroke is not something I will achieve in my lifetime. --mjm:bow:
Mswimming pretty much said what I would say. The problem with your math is that "1 stroke every .67 seconds" is not the same as ".67 strokes per second."
The power occurs exactly when the water molecules start pushing us forward (paired forces) at the "power position." So the purpose of our shoulders is to move our high elbows forward.
Exactly, for only in the "power position" can you extract the power of the water. The trick is to efficiently extract it with perfect technique and streamlining or it is wasted. Let the water be your friend and power source.:bump:
Re: where does the power occur,in my viewing of the velocity charts that Dr. G has shown in various publications the peak velocity usually occurs when the propulsive arm is about mid-chest,when it has both the maximum hand/arm area perpendicular to the direction of propulsion and the most large propulsive muscles employed.Provided the arms are moving backwards faster than the body is moving forward they cannot be causing form drag to slow you down,rather their form drag is the primary thing you are pushing against to move forward.Therefore you want to maximize the arm's form drag to maximize propulsion,hence EVF.
Re: the poll question,there are too many variables to answer it.Velocity off the block,height achieved in flight,angle of entry,and ,probably most important, ability to enter"through the key hole" will all affect the entry speed and deceleration.A more important question is what are the optimal angles in leaving the block and at entry and why.Many coaches seem to be teaching leaving the block nearly parallel to the water which gives limited flight time,therefor minimizing the time when you are at your fastest.Is that really wise?Should the angle be different with the new starting blocks?These are answers I'd like.
Chris: if you agree that distance per stroke = speed divided by stroke rate, then at 34 strokes for 50 meters, we don't have the same DPS or the same SR. The DPS and the SR are below:
Lezak: 50 meters in 23 seconds = 2.17 meters per second
34 strokes in 23 seconds = 1 stroke every .67 seconds
MJM: 50 meters in 35 seconds = 1.42 meters per second
34 strokes in 35 seconds = 1 stroke every 1.02 seconds
Lezak: 2.17 meters per sec./.67 strokes per second. DPS = 3.23 meters
MJM: 1.42 meters per sec./1.02 strokes per second. DPS = 1.39 meters
So I should have said Lezak and I can take the same number of strokes for 50 meters. However, his stroke rate combined with his distance per stroke is not something I will achieve in my lifetime. --mjm:bow:
Chris: if you agree that distance per stroke = speed divided by stroke rate, then at 34 strokes for 50 meters, we don't have the same DPS or the same SR. The DPS and the SR are below:
I think most people consider distance per stroke, (distance divided by # of strokes) . So for Lezak and you its 50M / 34 strokes = just under 1.5 meters per stroke.
Stroke rate is (# of strokes divided by some period of time). Lezak is 34 strokes / 23 seconds, Almost 1.5 strokes per second. You are 34 strokes / 35 seconds is less than 1 stroke per second.
The difference is that he can maintain that DPS at his higher stroke.
A while back, I jumped on the triathlon website Slowtwitch and got attacked for saying ......
Gary Sr.
Someone getting attacked for voicing their opinion on Slowtwitch? So what else is new. It can be a very helpful forum, but it can get brutal if the crowd turns against you. By the way I thought you handled yourself just fine. I just did not feel as comfortable about the product pushing that seemed to accompany your otherwise very insightful analysis.
Is this argument all about proving that increasing turnover is necessary to increase speed?
With all due respect to Mr. Hall Sr. who has forgotten more about swimming that I will ever know, isn't speed also about distance per stroke? I have no problem matching Jason Lezak's turnover rate (about 34 strokes for 50 meters) in the last 50 meters of his record Olympic freestyle relay. However, not in my wildest swimming fantasy, do I approach either his distance per stroke or his time. (Well, maybe in this one fantasy involving....no,no)
What interests me is how this power issue relates to distance per stroke.
--mjm.
Steve,
The key phrase in your analysis is 'if the drag forces remain constant'. In swimming, they don't. Far from it. The difference between the drag coefficients in water with the hand-in-front, outstretched position (other hand releasing) (relatively streamlined) and the arm-sticking-straight out position when hand is at chin or shoulder (very unstreamlined) is off the charts.
Taking an armstroke in freestyle is like streamlining, then throwing a parachute out the back, then cutting the cord to it and back to streamlining again...that occurs with each arm pull. That is why we decelerate into that horrible arm-out position in spite of a significant force being applied up front.
To appreciate the drag forces we are dealing with when our hand is at our shoulder underwater, try kicking fast with fins on with one arm over your head and the other sticking straight down. You will see what I mean about the parachute.
What makes swimming complicated to analyze is that we have significant changes in power from front end to back end of the pull with even more significant changes in drag occurring simultaneously. Now, throw in the propulsive and drag forces of a six beat kick and you have one complicated mess.
Yours in swimmming,
Gary Sr.
knelson,
You are right. The long dps guys use a hip-driven, leg-driven stroke (Phelps, Thorpe, Hackett, Lezak) and they are all dependent on having Mercury motors for legs behind them.
Strong legs not only add significant propulsion, they create lift and most importantly they help sustain speed (helping to overcome the inertia problem). If you don't have stong legs and you try to hold out in front like they do, you are sinking.
In other words, no legs and you'd better learn to increase your stroke rate.
Gary sr.
