When I swim breaststroke, I use the outsweep and insweep type of pull. I don't focus on pulling back at all. I read it somewhere that you should also focus on pulling back. WHen I tried doing that, my hands got stuck and my timing is off. Anyone has any thoughts?
Also, how wide should you pull? I sweep out to 12-15 inches outside my shoulder width, anchor my hands, then start insweep? I am concerned it might be too wide. When I tried anchoring my hands narrower, I don't feel as powerful of an insweep.
Thanks.
Originally posted by Allen Stark
Regarding lift,Bernoulles Principle is that as a fluid flows faster it's pressure decreases. An air plane wing is curved on top so the air has to travel further in the same time on top relative to underneath.
Your first statement is correct, but your second is not. This quote from Wikipedia describes the flaw in this statement:
Many readers new to this topic may be looking for the explanation that is commonly put forward in many mainstream books, and even scientific exhibitions, that touch on flight and aerodynamic principles; namely, that due to the greater curvature (and hence longer path) of the upper surface of an aerofoil, the air going over the top must go faster in order to "catch up" with the air flowing around the bottom (and hence due to its faster speed its pressure is lower, etc). Despite the fact that this "explanation" is probably the most common of all, it must be made clear that it is utterly false. There is no requirement that the air over the top must catch up to the air below, and in fact it does not do so. In addition, such an explanation would mean that an aircraft could not fly inverted, which is demonstrably not the case. It also fails to account for aerofoils which are fully symmetrical yet still develop significant lift. It is unclear why this explanation has gained such currency, except by repetition and perhaps the fact that it is easiest to grasp intuitively without mathematics. However, since it is wrong, the assumed intuition which serves it is also wrong, and the wise reader would do well to discount this approach.
I also want to say that lift does NOT contribute to swimming propulsion. Since lift is defined as a component of force perpendicular to mean flow, it is impossible for lift to accelerate you in the water. If would be more proper to say that Bernoulli's principle is used by swimmers to create thrust--not lift. The same thing could be said about a boat or airplane propeller.
OK, enough physics for today :)
Originally posted by Allen Stark
Regarding lift,Bernoulles Principle is that as a fluid flows faster it's pressure decreases. An air plane wing is curved on top so the air has to travel further in the same time on top relative to underneath.
Your first statement is correct, but your second is not. This quote from Wikipedia describes the flaw in this statement:
Many readers new to this topic may be looking for the explanation that is commonly put forward in many mainstream books, and even scientific exhibitions, that touch on flight and aerodynamic principles; namely, that due to the greater curvature (and hence longer path) of the upper surface of an aerofoil, the air going over the top must go faster in order to "catch up" with the air flowing around the bottom (and hence due to its faster speed its pressure is lower, etc). Despite the fact that this "explanation" is probably the most common of all, it must be made clear that it is utterly false. There is no requirement that the air over the top must catch up to the air below, and in fact it does not do so. In addition, such an explanation would mean that an aircraft could not fly inverted, which is demonstrably not the case. It also fails to account for aerofoils which are fully symmetrical yet still develop significant lift. It is unclear why this explanation has gained such currency, except by repetition and perhaps the fact that it is easiest to grasp intuitively without mathematics. However, since it is wrong, the assumed intuition which serves it is also wrong, and the wise reader would do well to discount this approach.
I also want to say that lift does NOT contribute to swimming propulsion. Since lift is defined as a component of force perpendicular to mean flow, it is impossible for lift to accelerate you in the water. If would be more proper to say that Bernoulli's principle is used by swimmers to create thrust--not lift. The same thing could be said about a boat or airplane propeller.
OK, enough physics for today :)
