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.
Clyde, I don't think it is as simple as a lever. Your hand does move when you pull back on the water, water is a fluid, not a solid. The force along your arm is what provides propulsion, and the distribution of forces along your arm is changing as a function of arm position. From a bio-mechanical point of view, your arm really is a class three lever, the load is distributed on the arm, the pectoral muscle is pulling on your upper arm and the shoulder is the fulcrum.
The force along your arm (and your body, for that matter) is due to the difference in velocity between your arm and the water. Different parts of your arm are moving at different speeds, so the game is to change the shape of the lever to provide the most efficient propulsion. EVF seems to be pretty good for that, as it pushes the water straight back earlier. But it depends on the swimmer...
Clyde, I don't think it is as simple as a lever. Your hand does move when you pull back on the water, water is a fluid, not a solid. The force along your arm is what provides propulsion, and the distribution of forces along your arm is changing as a function of arm position. From a bio-mechanical point of view, your arm really is a class three lever, the load is distributed on the arm, the pectoral muscle is pulling on your upper arm and the shoulder is the fulcrum.
The force along your arm (and your body, for that matter) is due to the difference in velocity between your arm and the water. Different parts of your arm are moving at different speeds, so the game is to change the shape of the lever to provide the most efficient propulsion. EVF seems to be pretty good for that, as it pushes the water straight back earlier. But it depends on the swimmer...
