Total Immersion origins/theory

but (some/most/all?) engineers just don't roll like that. I like that. There are other reasons, of course. One could be reduced to a simple question: How do you know that what you are being told is true? In my years in martial arts I have had some really fantastic teachers. Some of the best knew as much about physics as I know about underwater basket-weaving. While most of what they said, did or taught was on the money, every so often they'd say something that was clearly not rooted in reality. Of course, you listen and move on. You have to show respect for who they are. However, without an understanding of some of the fundamental physics and bio-mechanics other students might just think that what they are been told is, in fact, true. I've seen a trick performed at dojos that eventually made it into a commercial to sell you a "magical" bracelet. I'm sure you've seen it: A guy grabs an old lady by the arm and pulls. She quickly looses her balance. They she puts on this $20 bracelet. The guy grabs and pulls again and the woman stays in place, aided by the magical powers of the bracelet. I've seen this done with four people pulling on the demonstrators arms. Well, if you understand vector decomposition --the way forces distribute themselves based on how they are applied-- it is very easy to understand how to do the trick. And of course, you also understand that there is no such magic. This is an extreme example to simply illustrate that it is sometimes useful to truly understand why one is doing what one is doing. For example, I find myself questioning the very first instants of a "traditional" catch. The hand touches the surface of the water and you start to apply power. For simplicity, let's assume that you don't bend your hand at the wrist. Well, funny enough this is a vector decomposition issue. The force you apply to the water with your arm and palm will distribute itself based on some pretty well known principles. And so, at 15 degrees down from flat-and-level with the water surface only about 25% of the force you are applying is moving you forward. At 30% it goes up to 50% and at 45 degrees it's about 70%. I look at that and can only think: "Applying any power in the first 25 to 30 degrees of motion is a complete waste of energy". Well, funny enough, it seems that the TI folks are promoting the idea of inserting your arm in spear-like fashion into the water such that you start your catch or power stroke somewhere around 30 degrees down from the surface. On first inspection that makes a lot of sense to me. It would seem that you only really want to apply power from 30 to 30, meaning that you spear your arm into a position 30 degrees down from the surface at the start of the the stroke and the power stroke ends when your arm is 30 degrees from the surface on the back side. Looking at this oversimplification you could almost argue that 45 to 45 is the right range. Of course, I am over-simplifying. There are hydrodynamic factors that might come into play (like generating some lift due to the forward velocity you carry) and modifying the shape of your arm to improve the way forces are developed. One example of that might be tilting your hand downward at the start of the catch and trying to keep your palm pointed backwards for the rest of the stroke. Anyhow, some of the things that keep me up at night...

but (some/most/all?) engineers just don't roll like that. I like that. There are other reasons, of course. One could be reduced to a simple question: How do you know that what you are being told is true? In my years in martial arts I have had some really fantastic teachers. Some of the best knew as much about physics as I know about underwater basket-weaving. While most of what they said, did or taught was on the money, every so often they'd say something that was clearly not rooted in reality. Of course, you listen and move on. You have to show respect for who they are. However, without an understanding of some of the fundamental physics and bio-mechanics other students might just think that what they are been told is, in fact, true. I've seen a trick performed at dojos that eventually made it into a commercial to sell you a "magical" bracelet. I'm sure you've seen it: A guy grabs an old lady by the arm and pulls. She quickly looses her balance. They she puts on this $20 bracelet. The guy grabs and pulls again and the woman stays in place, aided by the magical powers of the bracelet. I've seen this done with four people pulling on the demonstrators arms. Well, if you understand vector decomposition --the way forces distribute themselves based on how they are applied-- it is very easy to understand how to do the trick. And of course, you also understand that there is no such magic. This is an extreme example to simply illustrate that it is sometimes useful to truly understand why one is doing what one is doing. For example, I find myself questioning the very first instants of a "traditional" catch. The hand touches the surface of the water and you start to apply power. For simplicity, let's assume that you don't bend your hand at the wrist. Well, funny enough this is a vector decomposition issue. The force you apply to the water with your arm and palm will distribute itself based on some pretty well known principles. And so, at 15 degrees down from flat-and-level with the water surface only about 25% of the force you are applying is moving you forward. At 30% it goes up to 50% and at 45 degrees it's about 70%. I look at that and can only think: "Applying any power in the first 25 to 30 degrees of motion is a complete waste of energy". Well, funny enough, it seems that the TI folks are promoting the idea of inserting your arm in spear-like fashion into the water such that you start your catch or power stroke somewhere around 30 degrees down from the surface. On first inspection that makes a lot of sense to me. It would seem that you only really want to apply power from 30 to 30, meaning that you spear your arm into a position 30 degrees down from the surface at the start of the the stroke and the power stroke ends when your arm is 30 degrees from the surface on the back side. Looking at this oversimplification you could almost argue that 45 to 45 is the right range. Of course, I am over-simplifying. There are hydrodynamic factors that might come into play (like generating some lift due to the forward velocity you carry) and modifying the shape of your arm to improve the way forces are developed. One example of that might be tilting your hand downward at the start of the catch and trying to keep your palm pointed backwards for the rest of the stroke. Anyhow, some of the things that keep me up at night...