[RC] _The Lame Horse_(was: the Physics of Weight) - k s swigartFrom: <heidi@xxxxxxxxxxxxxxx> <sigh> Truman, you really do need to go back and study mechanical advantages of levers, etc. I'm sure kat could give you a far better detailed description than I can While I have no desire to give a detail description of the operation of levers in the mechanism that is a horse, I can refer anybody who is interested to a good source. James Rooney, DVM's book, _The Lame Horse: Causes, Symptoms & Treatments_ is just such a source suitable for the "lay reader." In the preface he states, "I shall assiduously avoid all mathematis. It will be necessary, however, to use a few vectors and a few very basic mechenical illustrations. It is, after all, impossible to talk about mechanics without talking about mechanics." The book is (as the title suggests) about how and why horses go lame (i.e. their locomotor system breaks down in some way, and he restricts himself to the locomotor system) in the foreleg, the rearleg and the back. This aspect of the book makes for a very interesting read. However, what I found of even greater value was the way he prefaced his discussion of all the things that can go wrong with these systems with a description of how it is supposed to work when it is working properly. He starts with a description of "The Normal Foreleg" and explains where each of the bones is, their range of motion, how they attach to each other, the tendons, ligaments and muscles that act as forces (and more often as not opposing forces) on the levers that are the bones and how contraction and relaxation of the muscles and the timing of these things propels a horse forward (and keeps it from falling on its face while doing so, which is why the foreleg is more often a brake than it is an accelerator). This is the best text I have ever found with respect to describing how horses move which is with levers (bones) pulleys (muscles and their attached tendons), and springs (tendons and ligaments and muscles) and how it uses its own weight to propel itself forward. There are no cogs or gears in the mechanism that is a horse, so when a horse changes gaits (say from a walk to a trot) it is not truely changing gears, it is just changing the timing of its foot falls. However, the timing of the foot falls (and the swing phase) has an enormous impact on the amount of work the horse must do in order to propel itself forward. Truman is quite right about one thing, the levers and pulleys and springs are not actually doing the work for the horse; however, they are enabling the horse to get gravity to do some of the work for it. And he is quite right, the dolly is not doing any of the work for me when I move a bale of hay, it is just making it so that gravity moves the bale of hay for me because the path between the hay shed and the horses is slightly down hill. James Rooney's book does an admirable job of explaining just how this mechanism operates normally, and even his discussion of how and why the mechanism breaks down gives a good understanding of how it is supposed to work. For people who are interested in the nuts and bolts of the physics of it, he has also written a book, _The Biomechanics of Lameness in Horses_ which goes into much more detail; however, it does NOT assiduously avoid mathematics but rather dives right in to the nitty gritty, and, consequently the mathematics is extremely complicated. So I don't recommend it in the same way that I do _The Lame Horse_ which is "designed for all readers interested in the horse and is illustrated with more than 180 drawings, photogrpahs, and X-rays. The pony-clubber as well as the experienced horse trainer, the veterinarian and the novice rider may all derive both facts and ideas that should improve their work with the horse and stimulate further thought." [From the dust cover of the 1986 printing; although there is a new edition that came out in 1998] kat Orange County, Calif. =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Ridecamp is a service of Endurance Net, http://www.endurance.net. Information, Policy, Disclaimer: http://www.endurance.net/Ridecamp Subscribe/Unsubscribe http://www.endurance.net/ridecamp/logon.asp Ride Long and Ride Safe!! =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
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