My freestyle technique, what needs work?

Do you master EVF? How does your DPS compare when swimming using this technique compared to when using little less EVF little deeper pulling? SolarEnergy - Here is my best advice for your question. Below is what is called a "Stroke Frequency/Velocity Graph. The "X axis" is stroke cycles/min and "Y axis" is time for a 25 yard swim. The blue line is the test line, and represents the relationship between the speed and the frequency produced during the test for this individual. You will notice a good test produces a high r-squared number. The white line is a 10% "shift" in the velocity for any given frequency. Start at a slower speed that you can comfortably swim for 16 X 25's, and use a rest time that will let you swim without to much fatigue. You will need one of those metronome devices. Find a beginning training time, and set the metronome on the frequency that corresponds to the time on the graph. That time will be used for the whole set and try to swim that time as precisely as possible on every repeat. As soon as you are "dialed in" to the time, start to listen to the metronome, and dial in the frequency. You will find this might take a little time to get coordinated and it might take a couple of sets or even a couple of days to get everything dialed in. When you have that first point mastered, it's time to move to the blue 10% shift line. So for the same time you have been training, find the new frequency on the white 10% shift line, and reset your metronome. Repeat the steps above, using the same time but now dialing in to the new frequency. Continue with this cycle by alternating between the test line, and the 10% shift line and progressively work your way up the curve. Now you have an objective method of knowing exactly how your stroke technique is improving/changing. Over time, sizable shifts are possible with consistent attention using this method. There is not one set prescription to get onto the new line, and you will have to examine all parts of your technique. It might be a smaller kick, body alignment, or changing your pulling pattern. Have an open mind about what to change. However, whenever you get onto the new line, you have made an effective change without guesswork. Then pick a new point, and work your way up the stroke curve. One goal is to eventually get to a lap time that corresponds to your racing lap time. When that occurs you are training the same stroke techniques you need for the race. Ultimately you would want to do 4 sets of the 25's at least 3 to 4 times a week to make an effective change in technique in a reasonable period of time. Hope this helps...

SolarEnergy - Here is my best advice for your question. Below is what is called a "Stroke Frequency/Velocity Graph. The "X axis" is stroke cycles/min and "Y axis" is time for a 25 yard swim. The blue line is the test line, and represents the relationship between the speed and the frequency produced during the test for this individual. You will notice a good test produces a high r-squared number. The white line is a 5% "shift" in the velocity for any given frequency. Start at a slower speed that you can comfortably swim for 16 X 25's, and use a rest time that will let you swim without to much fatigue. You will need one of those metronome devices. Find a beginning training time, and set the metronome on the frequency that corresponds to the time on the graph. That time will be used for the whole set and try to swim that time as precisely as possible on every repeat. As soon as you are "dialed in" to the time, start to listen to the metronome, and dial in the frequency. You will find this might take a little time to get coordinated and it might take a couple of sets or even a couple of days to get everything dialed in. When you have that first point mastered, it's time to move to the blue 5% shift line. So for the same time you have been training, find the new frequency on the white 5% shift line, and reset your metronome. Repeat the steps above, using the same time but now dialing in to the new frequency. Continue with this cycle by alternating between the test line, and the 5% shift line and progressively work your way up the curve. Now you have an objective method of knowing exactly how your stroke technique is improving/changing. Over time, sizable shifts are possible with consistent attention using this method. There is not one set prescription to get onto the new line, and you will have to examine all parts of your technque. It might be a smaller kick, body alignment, or changing your pulling pattern. Have an open mind about what to change. However, whenever you get onto the new line, you have made an effective change without guesswork. Then pick a new point, and work your way up the stroke curve. One goal is to eventually get to a lap time that corresponds to your racing lap time. When that occurs you are training the same stroke techniques you need for the race. Ultimately you would want to do 4 sets of the 25's at least 3 to 4 times a week to make an effective change in technique in a reasonable period of time. Hope this helps... Here's my current technique. I'd like to compare it with yours, if you can provide some footage (instead of graphs). Pace 400m YouTube- 100m Free fast but controled Slow relaxed pace YouTube- Free style early warm up pace I'm more of a feeling sort of guy. I find the test a bit complex. I handle matters by eliminating a variable, working only with time and DPS. The rate, well is just resulting of the two others. DPS is set based on my ability to handle the load, the torque. If I feel I can't handle the torque, I voluntarily drop a stroke. In other words, I won't use a complex test. I always know how many strokes per lenght, and am always aware of time by looking at time clock on each turn. The last arm stroking prior turn tells me the count. I listen to the body, shoulder articulations, make sure the ghosts stay in closet, adapt the DPS like a cyclist would shift gear, go with what's available that day, and make sure the DPS chosen will retain throughout the event. In the two clips above, there's a delta of 1 stroke, for a delta of little less than 20s (1:07 vs 1:24). I probably sacrifice another stroke to get closer or under the minute. Lots of talk about EVF, lots of theory, lots of shoulds woulds, this and that, but yet still waiting to see one single execution from anyone that have been participating to these discussions.

Here is a little information about Aquanex that may resolve some of the issues in this thread: 1) Aquanex sensors measure the pressure differential between the palm and back of the hand. Because pressure is measured on both sides of the sensor, there is no variation in pressure due to depth. (As you lower a sensor underwater, the pressure reading remains at the baseline (zero). The sensors only measure pressure due to movement of the hand. 2) The pressure values are multiplied by the area of the hand to calculate force. Force values are displayed by the software. 3) Because the force values are based on pressure measurements, the direction of the force value is perpendicular to the sensor surface (i.e. hand surface), resulting in a slight overestimation of propulsive force. In a study of college females, we found a very high correlation between propulsive and total (measured) force (r = .98) with only about a 1 lb difference in average force. Although technically there is a little error, practically, it is irrelevant to a technique analysis. For example, if a swimmer’s palm is facing the bottom of the pool at the beginning of the pull, the arm is in such a weak and awkward position that very little (nonpropulsive) force is generated. Generally speaking, even the least competitive swimmers have their hand approximately perpendicular to the intended horizontal direction of body motion for the majority of the underwater arm motion. Rod Havriluk, Swimming Technology Research (manufacturer of Aquanex)

Fritz, would you agree that if you measure force on the palm of the hand with a pressure sensor that the pressure registered will increase with depth? And that to measure effective force you would need a second pressure sensor on the back of the hand so you could check the difference in pressures? You wouldn't need to measure pressure on the back of the hand, just have the pressure transducer measure two points, one going with the flow (pointed outwards from your hand) and one perpendicular to the flow (pointed up towards your wrist, for example). Subtract off the pressure from the perpendicular one and you're good to go. You could also subtract off the hydrostatic pressure (rho * g * H) if you knew the depth, but the easier way is to measure the static pressure and subtract it from the total pressure. The pressure increases with depth linearly, P_h = rho * g * H where rho is the density of the water (1000 kg/m^3), g is gravitational acceleration (9.81 m/s^2) and H is depth in meters. That is the easy part. The hard part is to calculate the actual sum of forces on a body moving through the water, wildly changing its geometry and interacting with the free surface. Gives engineers headaches, but it keeps them employed :D.

Here's my current technique. I'd like to compare it with yours, if you can provide some footage (instead of graphs). Pace 400m YouTube- 100m Free fast but controled Slow relaxed pace YouTube- Free style early warm up pace Lots of talk about EVF, lots of theory, lots of shoulds woulds, this and that, but yet still waiting to see one single execution from anyone that have been participating to these discussions. I got wet. Will you? Here is my current technique, though I haven't done any video of a relaxed pace. (lane 6, yellow cap, hurting the last length) YouTube- 100_free_harvard_2010.wmv My stroke count does go up when I sprint or when I get tired, it is usually around eight to ten and here it is ten to twelve. I've been trying the stroke frequency/velocity idea, but I haven't graphed it. That is a nice idea, to see where you are loosing efficiency.

Ahhh finally. I love your stroke. Your stroke count is misleading since it is tightly related to both the count of SDK and the efficiency of every SDK undulation. So it doesn't mean as much than for instance mine since I love breathing so much that I don't SDK :( So. Do you define your stroke as EVF? How was the transition? You certainly don't look like a dropped elbow swimmer to me, reach on water seems good. Do you use full blown very high and early vertical forearm or just manage to pour a bit of EVF to it? Any record of injuries? My SDK efficiency drops off rapidly with distance -- it works but the cost is fairly high. I also started swimming underwater on a couple of those turns, which is what I get for not racing since the mid '80s. I have been working on EVF, trying to hold onto it when I sprint. I think it is definitely more efficient and I can get more power to the water, but I tend to revert to my old stroke during a race. No injuries yet, and (with the speed suits) I'm fairly close to my college times while doing only 20% of the yardage. My recovery time sucks, though.

I don't doubt that drag forces grow with the square of velocity, that has been shown with more straightforward means than this experiment. And I will take back my comment about a straight line fitting the data just as well, clearly the velocity must equal zero when force is zero so a curve that passes through the origin is required.Lindsay - I agree It occurs to me that at a point just before the hand reaches shoulder level the swimmer is still decelerating, and at a point just after that the swimmer is accelerating. This suggests that the swimmer is exerting relatively little propulsive force while the arm is in the front quadrant.Lindsay - Based on the values from the sensors, it is pretty low. Would you agree that even when we arrive at the peak, if we accept for a moment the force numbers published, what would have been your estimation for the kind of force numbers you would have expected to see? Would you say that 30 lbs. of force requires large amounts of physical strength to move through the water effectively? Ok I understand. What I would like to see is a real stroke in action.George - Those files are in another computer, and I will try to get another swimmer at more regular speeds. The way the Woolies move in the images provided in general terms are pretty indicative of what we see generally through a stroke cycle. The swimmer in the images was a very fast swimmer, and we used him initially because he had really long arms. Sorry for the confusion earlier. May I hijack and request technique feedback for me too Steve - There is a better way to take all the guesswork out of what you stroke is doing...that I already suggested to you. :) fritznh - We have been using "Woolies" for a very long time. Everyone always thought it added some real visual value in conjunction with the Velocity Meter Telemetry. As I said before, we always tried to develop methods that take out as much of the guesswork as possible in lieu of the "belief system" approach.

What is the reading when the hand is in the right position to take a reading. I have yet to see any real numbers. I have only heard differences of 1 or 2 lbs.

May I hijack and request technique feedback for me too (wonder if we scared away the original author of this thread with all of our responses)? It looks like your right arm could use more bend in the pull. Interesting lighting in the pool! Can you get a side view?

I don't believe that the depth will have anything to do with the force, rather it is the mechanics of the stroke that allow you to exert force on the water. Fritz, would you agree that if you measure force on the palm of the hand with a pressure sensor that the pressure registered will increase with depth? And that to measure effective force you would need a second pressure sensor on the back of the hand so you could check the difference in pressures?