My freestyle technique, what needs work?

Question for TeamTermin Do you swim yourself? Do you master EVF? How does your DPS compare when swimming using this technique compared to when using little less EVF little deeper pulling?

Peak aceleration in #5 and peak velocity in #7 above:) 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)? YouTube- easy sprint.AVI

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. The drag should be close to the same at both points so it seems likely that the swimmer has fairly suddenly ramped up the force they are applying at this point. This suggests that the swimmer is exerting relatively little propulsive force while the arm is in the front quadrant.

I think you mean something like this...We call these "Woolies" Yep, those were what I was thinking about. Frame 3 shows the flow on the upper arm still going in the direction of body motion (the upper arm is moving forward) while the forearm is moving back providing propulsion. So the upper arm is dragging while the lower arm is propelling, like Gary mentioned. To me, frames 6 and 7 show the back half of the stroke doesn't provide a lot of thrust because the woolies show the arm is not providing a lot of thrust. The hand may provide some additional propulsion, but most of the flow along the arm shows that for the most part, the arm speed is not that high. The arm is producing some thrust, though. Interesting.

We can become too technical here. The guy in pictures makes many mistakes, even if he is a world class swimmer. I do not think he is. He is doing an awful lot of reaching and not getting into the proper stroke position soon enough. His hands and forearms are way out of sync.

We can become too technical here. The guy in pictures makes many mistakes,George - Don't get upset...he is just swimming like that in the video, just to demonstrate how the "Woolies" work. In this example he is actually swimming very slow, that is not his regular stroke and overemphaszing the left arm. It was for demonstration only. I just posted these because fritznh had mentioned them in his last post, and I wanted him to see what they looked like, that's all.

Ok I understand. What I would like to see is a real stroke in action. In those pics it reminds me of the Japanese swimmers in the 1956 Olympics. They laid out with the hands floating up to the top and actualy dropping the elbows and pushing against the water which raised the upper body and caused massive drag. But they were in great shape and could stay with or even beat the great swimmers of the time.

The pressure sensor is telling us that force is increasing from hand entry to mid stroke, but unfortunately depth and exposed arm surface and resulting drag would both produce a rising value through the front quadrant.So how does one explain that as force is increasing from the hand entry to mid stroke, that same phase concurrently produced the minimum velocity value for the stroke cycle. Wouldn't your logic say that as force/pressure increases through the stroke cycle, so should the velocity? From the 2004 FINA Paper you sited in the conclusions paragraph: Understanding this relationship is paramount to optimizing performance. Since a disproportionately larger increase in hand force is required to continue to increase swimming velocity, swimmers must be very conscious of generating maximum force and optimally directing the force at the higher swimming velocities. More precise information was included in a similar paper published in the American Swimming Coaches Newsletter: Notice the calculation about how much force it takes for minimal increases in resultant velocity, especially as velocity increases. Not only does the graph show that an increase in hand force is related to an increase in swimming velocity, but it also shows how critical hand force becomes at the higher swimming velocities. A disproportionately larger increase in hand force is required to continue to increase swimming velocity. The regression line shows that a 5 lb increase in force results in a .25 yd/sec increase in velocity in the 1.0 to 1.5 yd/sec range, but only half that much in the 2.0 to 2.5 yd/sec range. Why does 5 lbs. of force only produce very small increases in velocity (.25 yd/sec) at slow speeds, and only half that (0.125 yd/sec) as the velocities get higher? That calculation comes from the shape of the curve, but consider the following: For swimmers at the surface, measured pressure drag increases to the second power and wave drag increases to the fourth power as velocity moves between 1.5 meters/sec to 2.2 meters/sec. (Typical competitive swimming speeds) The significant increase in drag negates the effects of increasing force on velocity.

PSI during the catch phase should be a constant (hand pressure) 25lbs+ psi or am I wrong?? PSI from entry to catch increasing from 5 to 10 lbs psi.

Hi Budd, The issue is that net force = propulsive forces - resistance forces A positive net force will cause acceleration and a negative net force will cause deceleration. From the velocity meter we can tell that the swimmer is slowing down in the front quadrant (ignoring the bump) and that net force is therefore negative. What we can't tell is the magnitude of the propulsive and resistance forces: -5 = 0 - 5 -5 = 10 - 15 -5 = 100 - 105 Pressure increases linearly with depth so as you move your hand deeper into the water the pressure on the palm of your hand will increase as your hand goes deeper and a pressure sensor on your palm will register increasing force. But the back of your hand is also going deeper and the force on it is also increasing. In this case the forces on the two sides of your hand cancel one another out and there is no net force, even though pressure on the palm is increasing. As you pull your hand backwards through the water you increase the force on the palm of your hand and decrease it on the back of your hand and that unbalances the forces and creates propulsion. Gary suggested that the drop in speed was due to increasing drag on the upper arm and cited the velocity profile as evidence of that. Since force on the palm is increasing while in the front quadrant but body velocity is not, one hypothesis is that at the same time that the hand is increasing propulsion the upper arm is increasing drag even more so the net result is that the swimmer decelerates. The drag from the upper arm is small when it is pointed directly forward and gets larger as it extends downward to a maximum when it is pointed straight down. We know that even if the swimmer kept their hand out front they would still slow down due to the overall drag that isn't countered by any propulsive forces (other than the kick). There are multiple plausible explanations for the observed data, what is needed now is a method to narrow down the list. Observing the readings from the Aquanex with increasing depth would be a good start. Measuring the deceleration of a swimmer who stops their stroke cycle with their arm extended would help. 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. So how does one explain that as force is increasing from the hand entry to mid stroke, that same phase concurrently produced the minimum velocity value for the stroke cycle. Wouldn't your logic say that as force/pressure increases through the stroke cycle, so should the velocity? From the 2004 FINA Paper you sited in the conclusions paragraph: More precise information was included in a similar paper published in the American Swimming Coaches Newsletter: Notice the calculation about how much force it takes for minimal increases in resultant velocity, especially as velocity increases. Why does 5 lbs. of force only produce very small increases in velocity (.25 yd/sec) at slow speeds, and only half that (0.125 yd/sec) as the velocities get higher? That calculation comes from the shape of the curve, but consider the following: For swimmers at the surface, measured pressure drag increases to the second power and wave drag increases to the fourth power as velocity moves between 1.5 meters/sec to 2.2 meters/sec. (Typical competitive swimming speeds) The significant increase in drag negates the effects of increasing force on velocity.