Where does the power occur?

RE: Where does the power occur?

Former Member — Wed, 02 Dec 2009 11:02:04 GMT

"I don't view hand and arm in the stroke cycle as "paddling" in that you move water backwards. Rather it's kind of like doing a one armed pull-up on an underwater ladder. As each hand grabs onto a rung, you pull yourself past the point where you latched on. It's just a slightly different take on what's going on under the surface." Even in paddling, the objective is not to move water backwards, but to move the boat (like the body) forward (past the blade or hand). So like the hand, the paddle doesn't move backwards, but remains fixed in location. And like your "underwater ladder," I actually practice on land using a four (4) foot long skateboard and propel myself with the swim stroke. My neighbors think I'm nuts going up and down the sidewalk, but boy, my shoulders get a workout. I wear leather garden gloves and get my hips involved too. If you have access to an outdoor basketball court with a smooth surface, try flinging yourself with one-arm pulls. Doing this will give a good mental picture of how far the body travels during the swim stroke in relation to arm position. Of course, even on land, my hands always exit ahead of where they begin the stroke. ps: please wear a helmet if you try the skateboard drill. thank you, clyde

RE: Where does the power occur?

dsyphers — Thu, 26 Nov 2009 11:09:34 GMT

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!

RE: Where does the power occur?

Former Member — Wed, 25 Nov 2009 06:10:19 GMT

Regarding the poll, supposed we convert it into a swim stroke: Then I'd be only 75% efficient and 25% lost to slippage?:2cents: Happy Thanksgiving

RE: Where does the power occur?

Former Member — Mon, 23 Nov 2009 09:37:33 GMT

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?

RE: Where does the power occur?

Former Member — Sun, 22 Nov 2009 10:05:10 GMT

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.

RE: Where does the power occur?

Former Member — Sun, 22 Nov 2009 06:47:18 GMT

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.

RE: Where does the power occur?

Former Member — Sat, 21 Nov 2009 12:19:00 GMT

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.

RE: Where does the power occur?

Former Member — Sat, 21 Nov 2009 09:44:54 GMT

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.

RE: Where does the power occur?

Former Member — Sat, 21 Nov 2009 07:40:44 GMT

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.

RE: Where does the power occur?

Former Member — Sat, 21 Nov 2009 07:03:51 GMT

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.

RE: Where does the power occur?

Former Member — Fri, 20 Nov 2009 09:55:00 GMT

RE: Where does the power occur?

Former Member — Fri, 20 Nov 2009 08:48:38 GMT

RE: Where does the power occur?

Allen Stark — Fri, 20 Nov 2009 01:55:37 GMT

I disagree. Lift is a component of force perpendicular to the mean flow. Since we're moving forward in the water, lift can only affect our body position, not move us forward. The only thing moving us forward is a propulsive force with a forward compnent caused by the arms and legs reacting against the water. Kirk,you are right about the direction,but the key is the hands,not the body. When the hands generate lift it is because they are moving side to side relative to the body(the old S stroke idea) and that "anchors" the hand allowing it to be used for thrust.Sculling is lift generated propulsion.It works,just evidently not as well for freestyle as the more drag dominant EVF pulls currently in vogue.

RE: Where does the power occur?

Former Member — Thu, 19 Nov 2009 17:54:28 GMT

Where's that physics prof?

RE: Where does the power occur?

Former Member — Thu, 19 Nov 2009 16:18:01 GMT

Does lift in the stroke keep you higher in the water creating less drag? Or does the added "surface turbulence" just slow you down? I have no hard numbers to compare, but my Early "Nearly" Vertical Forearm stroke has evolved to my elbows barely below the water surface .....with the forearm at about 5 - 10 deg. to perpendicular to the bottom.....creating some lift. I will concentrate on perpendicular (no lift)to see what outcome. Georgio :bolt: :bliss::argue:

RE: Where does the power occur?

Former Member — Thu, 19 Nov 2009 14:20:06 GMT

Where's that physics prof? His presence would be a bonus, but all that has been throughly studied, analyzed and described since 1980 by Ernest Maglischo. And again, to better guess when the power occur just perform one-arm freestyle. It then becomes clear.

RE: Where does the power occur?

Former Member — Thu, 19 Nov 2009 14:14:29 GMT

Dear Tomtopo, I have not seen the research from the Olympic Training Center, but I can tell you that one cannot determine power by knowing what the velocity, acceleration or deceleration is at any given moment in the stroke cycle. The reason is that one can accelerate (or decelerate) by either a change in propulsive power or a change in resistive drag or a combination of both. Most objects we study in motion do not change shape, but the motion of the human body swimming freestyle is complicated by both changes in propulsive power and drastic changes in shape, significantly increasing pressure drag, as the arm moves through the underwater cycle. Although there is deceleration (40% loss of speed) of the body from its fastest point in the cycle (with arm outstretched and other arm preparing to release) to its slowest point (with upper arm nearly perpendicular to the body line, hand about at the chin), I submit that this deceleration or loss of speed is not due to reduction of power but rather to a huge increase in drag force. Anatomically, it makes no sense to say we have no power in front when virtually all of the muscle groups are working. By the time we release the hand, very few muscles are left working (tricep?). The power generated is also influenced by the counter-rotation of the hips (core), creating a counter force against which we pull, which is initiated with the catch and continues during the entire underwater pull. The strongest argument one can make for believing there is significant power in the front quadrant is that we spend half of our cycle time in that front area. The other half is spent in the back quadrant and the complete over water recovery....ie hurrying to get our arm/hand back out in front again. If we weren't getting power there, I don't think we'd be spending so much time up there. Gary Sr.

RE: Where does the power occur?

Former Member — Thu, 19 Nov 2009 13:43:42 GMT

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.

RE: Where does the power occur?

knelson — Thu, 19 Nov 2009 12:42:09 GMT

Also consider that, if we're doing it right, our stroke is getting a little bit of help from lift, which is actually moving our hand forward. I disagree. Lift is a component of force perpendicular to the mean flow. Since we're moving forward in the water, lift can only affect our body position, not move us forward. The only thing moving us forward is a propulsive force with a forward compnent caused by the arms and legs reacting against the water.

RE: Where does the power occur?

Former Member — Thu, 19 Nov 2009 11:35:47 GMT

Also consider that, if we're doing it right, our stroke is getting a little bit of help from lift, which is actually moving our hand forward. If not, then the hand stays put (fooling around with drag) while our arm changes position indicating continuously how far our body has moved forward.

RE: Where does the power occur?

Former Member — Wed, 18 Nov 2009 13:55:36 GMT

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'd be tempted to say that the reason why your fastest point in th estroke cycle be when hand first enters the water, is that whilst this is occuring, the other hand has just finished its job, that is ensuring the the peak power occurs near the end of the stroke. Peak power during the pulling path in Free Style occurs by the second half of the pulling. Gary, there's one very simple way to experiment and measure this: Swim with one arm only!!

RE: Where does the power occur?

Former Member — Wed, 18 Nov 2009 13:14:36 GMT

In my opinion the "magic" here is kicking hard. I don't care how efficient your pull is, there's no way your hands exits ahead of where it entered unless your kick is propelling you forward. don't forget that after the hand enters there is arm extension, maybe some glide, then a drop to the catch position. during all this time you(and your hand) are still moving forward even if you are using a pull bouy. by the time you start to pull it is not hard to imagine that the hand is well ahead of where it entered the water. if the distance from hand entry to hip is roughly 4ft and you can pull 25yds in 15 strokes then each arm stroke is moving you about 4ft assuming a 5yd pushoff. of course sadly for me, a good kick also helps.

RE: Where does the power occur?

Former Member — Tue, 17 Nov 2009 12:29:02 GMT

It's nice to partition the stroke, but only if the body remains still. However, the body moves forward and the hand remains fixed in location and ideally exits ahead of where it entered.:angel:

RE: Where does the power occur?

Former Member — Tue, 17 Nov 2009 08:45:53 GMT

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).

RE: Where does the power occur?

Former Member — Mon, 16 Nov 2009 10:50:31 GMT

OK....I have kept everyone in suspense long enough. The answer to the poll question is that an excellent swimmer (my son Richard 1:37 200 free in college) who does a very clean sling shot racing dive, hit the water at 14.8 MPH and at one second from that time (he is now completely submerged, streamlined and even starting a kick) he has slowed to 3.5 MPH, quite a bit slower than his race speed. That is a 76% reduction in speed that occurs in exactly one second with an excellent dive. Congratulations to those of you who got it right. The moral to the story is unless you have legs like Phelps, Lochte, Leveaux, Coughlin or Hyman, you'd better get your rear end up to the surface and start swimming. Otherwise you are just losing ground. Gary Sr.