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.
Former Member
books.google.com/books
Page 9
- Paragraph on Lift
Page 11
- Paragraph on Bernouli's Principle
Page 18
- Paragraph on Newton's Third Law of Motion (don't miss the Q/A FAQ)
Finally, I think that both Maglischo and Councilman are on the same page. In fact, they have been in synch over years. They both went wrong in thinking that Lift was mainly responsible for forward thrust (more than a decade ago).
Appreciate the reference SolarEnergy, for it is a matter of contribution, which Ross Sanders brought up years ago. Also noticed that there is no discussion on Newton's 2nd law of motion: acceleration. Yes, water will accelerate backwards, but before it does, it accelerates us forward, and that is the period we want to exploit.
books.google.com/books
Page 9
- Paragraph on Lift
Page 11
- Paragraph on Bernouli's Principle
Page 18
- Paragraph on Newton's Third Law of Motion (don't miss the Q/A FAQ)
Finally, I think that both Maglischo and Councilman are on the same page. In fact, they have been in synch over years. They both went wrong in thinking that Lift was mainly responsible for forward thrust (more than a decade ago).
I agree in that lift forces are not the primary propulsive force in the freestyle. Drag and lift forces will never be in "vogue" they wil always be a matter of fact. Every single person on the face of the earth, who wants to propel themself more effectively, must put their hand and forearm in a vertical position and the quicker the better, thus the EVF. An early vertical forearm is no more in vogue than an effective kick (making it better makes you faster). The force of the hand as it enters, is in, and as it exits perpendicular, establishes the most propulsive force in swimming. Movement of the hand to and away from the midline of the body allows maximum pressure because moving the hand straight back causes the water to create a vortex (behind the hand) that decreases drag. A person's strength and flexibility are just two important variables that determine how effective a swimmer's pulling pattern can become. We can all rationalize (and very well) how force is created in a freestyle swimmer's pull but we should all agree that the vertical position of the forearm and hand is not in vogue but a constant reality to freestyle swimming.
In that regard a totally straight arm pull (not including the release or finish) achieves a perpedicular position later and can maintain propulsive force, especially when you have a tall swimmer with strong shoulders (Alain Bernard).
Can a freestyler like Alain Bernard swim faster if he improved his EVF? The answer should be an immediate yes because a totally straight arm negates the propulsive opportunity during the "setting up of the stroke" or beginning of the first quadrant. Bernard's stroke doesn't have to change to one that looks like Rebecca Adlington's but a quicker EVF would certainly help in my opinion.
I must tell you that I have found this thread to be very interesting. I do think that the research done by Doc, is still the best for what swimmers want to know, and that's how to swim faster. Doc's book should be on everyone's shelf.
And depending on how much fulcrum (water) you want to use, your hand and arm will adjust accordingly to achieve this in order to increase the duration of the propulsive phase of the stroke.
And depending on how much fulcrum (water) you want to use, your hand and arm will adjust accordingly to achieve this in order to increase the duration of the propulsive phase of the stroke.
Clyde ~ You said this very well and I'd like to rephrase it. Swimmers who can adjust and increase the duration of the most propulsive phases of each competitive stroke are going to improve their swimming performance. I hope you don't mind me using this because it is really at the core of many threads on many swimming forums. Thanks, Coach T.
Clyde ~ You said this very well and I'd like to rephrase it. Swimmers who can adjust and increase the duration of the most propulsive phases of each competitive stroke are going to improve their swimming performance. I hope you don't mind me using this because it is really at the core of many threads on many swimming forums. Thanks, Coach T.
Coach T: Why of course not, please continue to spread the gospel and help us swimmers achieve better performance.
I really enjoy trying to help. This is becoming a super site for swimming information and t's fun to be involved. I hope my two-cents helps. Good luck, Coach T.
I do think that the research done by Doc, is still the best for what swimmers want to know, and that's how to swim faster. Doc's book should be on everyone's shelf. I think so too. And shame on me, I do not own any of these. So far I have been counting on Maglischo to provide me with a synthesis of all these works.
But yeah. It seems that Doc's works on this topic over years have shown several other researchers the right way.
Also. Note that Maglischo (and others) still don't know about these things. It's all hypothesis. Therefore I don't pay that much attention to this.
Put yourself in my position. I have been following Maglischo's work since his first edition. Every new edition he changes his mind drastically. So... What is it going to be next?
Where's that physics prof?
Sorry to have been silent on the rest of this thread. I've been buried under a mountain of work, chairing our tenure committee with meetings deep into the evening, and pitching in while my wife dealt with her mother's decline/death this month.
The general principles, most of which are being discussed in this thread, are pretty clear -- thrust, drag, lift (in that it changes body position in the water), and turbulence. Beyond that, the specifics really require measurements of force as a function of time, speed as a function of time, etc. correlated with the motions of the swimmer. There is currently some research being done along these lines, and I expect we'll see some general principles come out of this work. They may not be that different from some of the general principles (like EVF) that have been around already.
However, the situation of each of our own bodies moving through the water is sufficiently complex, that what is really useful is to have your own personal self tested while you swim. Systems in development now will make that easier in the future, but now they are mostly in the research stage. I'll be tested myself in a couple of weeks using the research system at my college, but it is still a little early in the research cycle to be able to take the data and unambiguously relate motions, or changes in motions, to the data. Why is it so hard? Even subtle differences in body position create differences in drag; applying forces to the water creates turbulence, as does changes in body position, and turbulence decreases the effectiveness of the applied force, etc. Figuring out the relative importance of all of these individual components (with all the swimming motions together) when they are all combined to give only 2 pieces of information (the net linear force in the direction you are swimming, along with your speed, both as a function of time) is not as easy as you might think.
Happy Thanksgiving to all!
