Structure & Movement - Page 1

Hi ecs, Your point is well made and taken (so spoiling good sport!) Correct me if wrong, but you assert that croup angle is directly related to arc of rear swing of hind legs. The steeper croup/pelvis angle, the more reduced this swing back becomes – as does amount of power produced – or, this is ‘where the action ends’. The only other alternative being the mentioned ‘kick up’. You also mentioned that power produced is measurable by difference in extended and retracted hind limbs. Perhaps you could expand further on this. It strikes as reasonable notion but other factors must surely also play a part. As well, the issue I wished to raise with SueB was how angle of croup is also a direct function of way drive produced is delivered into dog’s back- ie, not too high so as to be partly lost by raising back instead of being thrust forward (as result of steep pelvis), and similarly not too low (because of inadequately angled pelvis bone - less likely of course). I think situation may be slightly different for galloping animal where powerful hind thrust may push dog more upwards – this drive then being picked up by equally powerful and more flexible shoulders etc – thought I ‘d toss that in for whatever worth! Look forward to SueB’s return as well and input of others – including Lennie.

Good Morning Sugarfoot and all the World, It is too early for me to think well at present, but coffee is perking and caffine is just moments away. It's difficult to operate on so few hours as this AM. however, let me see if I can state this as incoherently as possible under the circumstances. Let me do this by example. Let us imagine we are watching a dog move in slow motion and we are concentrating only on the rear assembly. We pick up the motion as the stifle bends as it moves forward. Momentum carries the foot to a point and the weight of the rear is pole vaulted so to speak, forward. The foot absorbes the shock, stabalizes itself, the body moves over the foot, and as the body, or better the rear assembly, the foot begins its duty and begins to push, or drive. Now let us say that we have a dog that is a pretty angulated animal with fairly long lower theigh. Normally one would think that the push would be as long as the lower theigh would allow and finish as forward progress would pull the lower theigh forward and the process could begin again. However, if we have a croup that points toward a point before that push is normally completed, that energy must go somewhere. The croup will not allow the lower theigh to complete its journey. So, it must disapate its energy and is done so by raising its feet or kicking-up. Hope that is clear. Coffee is ready so will leave to caffine-up. ecs

Lenny please, not Lennie.

The croup is the fulcrum of the rear quarter. If it is ideally angled at near 30 degrees(and the femur and tibia and hock are the correct length) the assembly will stroke correctly i.e. there will be maximum under reach and correct follow through. If the croup is steep the under reach will be free but the follow through will be restricted. If the croup is flat the under reach will be limited and the follow through will kick up behind. When you tilt the croup you tilt the stroking action of the assembly, thus the fulcrum designation. When strength is considered the primary factors are muscle, tendons( the white sinewy tissue that connects the muscle to the bone) and ligments. To briefly discuss "lenghts" there are four bones that should be approximately the same size, the femur, the pelvis, the scapula and the humerus. The tibia must ideally be 20% longer. At these lengths the bones of the fore assembly and the bones of the rear assembly will parallel each other in the static position i.e. when the feet in the rear quarter are directly under the hip socket, and the lower arm is directly under the peak of the wither in the fore assembly. There is a lot more to this subject than I have room for here.

I agree with both previous writers with regard to the croup. However, one cannot concentrate on aspect alone when you consider movement per se. The entire skeleton plays a part. If you are talking only of the hindthrust, you must also take into account the hind angulations. An over- or under angulated dog will never move as well as a well-angulated dog. Also the body-length. A short compact bodied dog will appear beautiful in slow movement, but when it comes to the gait, there is simply no space for it to put its back legs! They need that bit of length in the loin area. you must also take into account the hocks - long, loose hocks impacts very seriously on movement. And so you can carry on .............

Lenny and ecs (apology for misspelling Lenny), Is it possible we’ve actually got something useful going here? Ecs: I agree wholly with described movement and how steepness in croup/pelvis – or one too flat – hinders or affects arc of rear swing. Could never have explained it so well! Lenny: tremendous new input – humbles our earlier efforts! Seeing croup/pelvis as fulcrum is very apt description. Other than impacting on width of thigh, I think that length of pelvis is fairly well a constant within any particular Breed. And mostly we find lower thigh (tibia/fibula) too long in relation to the upper (or femur). And, of course, too long a lower thigh combined with longer hock leads to instability in the latter. The knee, because of amount of work absorbed, is of course also of prime importance – as well as being another major pivot? A straighter stifle – ie, because of insufficient angulation – similarly leads to instability as well as again for hock. You say tibia must ideally be 20 percent longer than other bones – could you explain underlying rationale here? Hi PZDC, I don’t think any of us have actually overlooked importance of overall structure. You’ve got to start somewhere! Besides, Lenny noted importance of correct fore and hind bone lengths and related parallelism. And I noted earlier how for any Breed balanced fore and hind bone length ratios meant harmonious movement. Something which I believe holds true for any Breed – any four-legged mammal? I agree that length of loin (or coupling) is vital part of equation – too long, and part of power produced is wasted trough ‘sloppy’ back movement – too short and dog can’t get quarters underneath itself or extend properly. I’d rather hoped that someone would show how angle of croup/pelvis not only affects to and fro swing of hindquarters, but also how drive produced is angled or thrust into back in a parallel direction to lay of pelvis bone. Thus, if pelvis is too steep, so is direction of thrust generated – and the reverse if this bone is laid too flat. In other words, the importance to have correct lay of croup is possibly under-estimated in more than one way. More to come?

Why 20% longer on the tibia? I explained that it is required to form a 90 degree angle in the static position. The GSD must have the same angle at each end if he is to cover the same amount of ground in front and rear. The result of 90-90 is ideal coordination, rhythm, and timing, i.e. the ideal two beat gait.

Hi Lenny, Like to, but just can’t see how lower thigh (or tibia) should be 20 % longer than other bone mentioned, unless you’re including length of hock here. I’ve always understood that ideally length of lower and upper thighs ought to be equal in length. And that one should then be able to lift rear leg up vertically so that point of hock touches end of pelvis – past it, tibia is too long, in front and it is too short. Please don’t ask where this comes from as I wouldn’t even know – always took it as a given! Mean to say - longish foreleg is also desirable and lengths of pasterns and hocks are variable. Just to round this off, sturdiness of hock is of course directly related to its own length and that of upper/lower thighs. Too much length making for sloppiness in movement, if not cow-hocked stance when joined to too much overall hind angulation – relatively shorter hocks normally encourages more effective delivery of drive.

Best of luck.

And to you sir.