Conventional and EVF can be one in the same unless a conventional swimming stroke means purposely dropping your elbow. The pulling pattern should never be straight back because the longer and the harder the hand moves backward the greater reduction in drag force (negative drag coefficient). The hand must move (scull slightly) into less turbulent water so peak drag force or pulling power can be maintained. As strong swimmers begin to improve their EVF, sprinters will begin to evolve into more right angled looking strokes like Rebecca Addlington's and less like Alain Bernard's. With everything being equal, a stroke like Bernards, in my opinion, can become faster by getting his forearm/hand vertical earlier. With that being said, Bernard may have anatomical factors (weak shoulder cuff, flexibility issues, EVF strength conversion habit issues) that could prevent that EVF alteration (his coach knows best). My contention is that any swimmer who can, without compromising anatomical health, improve the length of time they can keep their hand/forearm in the vertical position and improve how early they can get their hand / forearm in a vertical position, will drop time. I think conventional (as long as it doesn’t mean purposely dropping your elbow) and EVF are the same and physical limitations and training habits create the variances from swimmer to swimmer. The fastest swimmers in the world may have different looking strokes but the winners keep their hands/forearm in the vertical position earlier and in a vertical position that produces the most power the longest. Getting your hand / forearm in a power position early and keeping it their longer, isn’t all about pulling strength, it’s more importantly about the ability to resist dropping one’s elbow. I started doing an exercise where swimmers kick 50 yards with fins, holding their arms in front of them (breathe to the side or in the front), holding an EVF position. Try it and it will show you the ability to “set-up” your stroke early (conventional or not) is more difficult than you can imagine. The pressure of simply swimming forward requires strong shoulder-cuff stabilizing muscles ( supraspinatus, infraspinatus, teres minor, and subscapularis) and the above exercise will show you how weak or strong yours are. I think it’s safe to say, more often than not, swimmers don’t have the necessary shoulder cuff strength that allows them to properly “set-up” their stroke. And, let’s think about it, if you can’t keep your arm in a “set-up” position (conventional or not) for 50 yards, what are the chances of ever developing a better “set-up position until you strengthen and train to improve the muscles responsible for that position. I think isometrics and the use of surgical tubing offers the most effective way to improve shoulder-cuff strength. Email me at tomtomp@netzero.com if you’re interested in more information. Good luck, Coach T.
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I have an experiment you can try at the pool: drag your hand through water at constant velocity and see whether the water stops pushing on your hand once you have "accelerated" it.
If you pick up a handful of water and throw it through the air you can use Newtons second law to calculate forces because the density/viscosity of air is low enough to ignore. If you attempt to "throw" a handful of water underwater the results are entirely different and F=ma will be entirely inadequate to model it.
en.wikipedia.org/.../Viscosityen.wikipedia.org/.../Newton's_laws_of_motion
As discussed in another thread your body is accelerating forward during the pull, your hand needs to accelerate backwards a like amount or it will actually be decelerating relative to the water.
The fact that your hand doesn't usually move in a straight line backwards can be adequately explained by the geometry of your limbs and your roll. It is impossible to move your elbow in a straight line relative to your shoulder, the elbow will always fall somewhere on the surface of a sphere centered on you shoulder. Yes, that is a slight simplification given the mobility of the shoulder but in the gross picture it holds. Assuming that all movements have some propulsive rationale will lead you into the lift force nonsense that prevailed for a couple of decades in the swimming literature. Propulsive forces actually drop during sculling motions in freestyle.
I have an experiment you can try at the pool: drag your hand through water at constant velocity and see whether the water stops pushing on your hand once you have "accelerated" it.
If you pick up a handful of water and throw it through the air you can use Newtons second law to calculate forces because the density/viscosity of air is low enough to ignore. If you attempt to "throw" a handful of water underwater the results are entirely different and F=ma will be entirely inadequate to model it.
en.wikipedia.org/.../Viscosityen.wikipedia.org/.../Newton's_laws_of_motion
As discussed in another thread your body is accelerating forward during the pull, your hand needs to accelerate backwards a like amount or it will actually be decelerating relative to the water.
The fact that your hand doesn't usually move in a straight line backwards can be adequately explained by the geometry of your limbs and your roll. It is impossible to move your elbow in a straight line relative to your shoulder, the elbow will always fall somewhere on the surface of a sphere centered on you shoulder. Yes, that is a slight simplification given the mobility of the shoulder but in the gross picture it holds. Assuming that all movements have some propulsive rationale will lead you into the lift force nonsense that prevailed for a couple of decades in the swimming literature. Propulsive forces actually drop during sculling motions in freestyle.
