Light Boned vs. Heavy Boned?

[k9kreationz]

You may find the contents of this article interesting:

http://www.thekennelclub.org.uk/dow...-of-differing-jump-heights-in-Dog-Agility.pdf

In particular, the height-weight ratio is discussed as a factor.

Height to weight ratio is a factor in jumping ability. Dogs with a ratio of less than 2.5 are the most capable, between 2.5 to 4 can be equally capable but may expose themselves to greater physical stresses, dogs with a ratio of greater than 4 are in the danger zone for jumping and should be trained with great care.

Interesting. So less than 2.5 height/weight ratio is better. Gawd, Koji's about 1:1. And also length of leg is important too. Koji has length, but maybe a bit too much. He'd probably be a lot better if his structure was correct. However, the art of sleeping doesn't seem to care about height/weight/leg length

 

[3Stars]

I found a lot of it interesting. Here's the Cole's Notes version :

In order to jump successfully, a dog needs to raise its centre of gravity high enough for all of its body to clear the height and width of the jump. The ability to raise the centre of gravity is determined by conformation, confidence and experience.

Whilst the front assembly therefore is shown to be extremely important in lift, the ability to land successfully is a consequence of the absorption of energy on impact and the follow through of the rear legs into a running gait.

Continuing with the analogy of shock absorption, a dog with greater angulation can also absorb the impact of landing better than a dog with a straighter front assembly.

Zink concludes that dogs with a weight height ratio of greater than 4 are in the danger zone for jumping and should be trained with great care, those in the 2.5 to 4 range are not stressing their bodies as much but are less likely to have a long jumping career, whilst those with a ratio of less than 2.5 are likely to be the most successful.

(Starr is at 1.7)

Another structural factor is body length in relation to height. Dogs that are significantly longer than they are tall bear more weight on their front legs and are therefore disadvantaged.

Finally we must consider leg length. A dog whose legs are greater in length from the ground to the elbow as a percentage of the dog’s height at withers has the advantage of a higher centre of gravity. During jumping, the
majority of the lengthening of the leg takes place above the elbow, with this joint acting as the fulcrum from which the leg extends. It is an advantage in jumping to have that height as high as possible in relation to the height of the jump.

Dogs that jump with a flatter trajectory experience less deceleration and less vertical impact on landing,and thus suffer less stress to the front end. Over the lifetime of an active dog, the reduced stress on the carpal joints, elbows and shoulders means fewer soft tissue injuries and a reduced incidence and/or severity of arthritis.............

So what I got from this is that when it comes to shelties, while weight is important (ie. being under that 2.5 ratio, which most shelties would be), conformation and training is even more important. So if I have a dog with proper conformation, and I train him to jump properly and land properly in a variety of circumstances (especially on angles), and I condition him appropriately, then he should be able to have a long, safe agility career.

 

[Sealtainn]

Quote:
Dogs that jump with a flatter trajectory experience less deceleration and less vertical impact on landing,and thus suffer less stress to the front end. Over the lifetime of an active dog, the reduced stress on the carpal joints, elbows and shoulders means fewer soft tissue injuries and a reduced incidence and/or severity of arthritis.............

So what I got from this is that when it comes to shelties, while weight is important (ie. being under that 2.5 ratio, which most shelties would be), conformation and training is even more important. So if I have a dog with proper conformation, and I train him to jump properly and land properly in a variety of circumstances (especially on angles), and I condition him appropriately, then he should be able to have a long, safe agility career.

I also read from this that this research acknowledges that asking a dog to jump higher adds greater stress and increases risks to long term health.
e.g. asking a 16.5" sheltie to jump 22" in USDAA Championship poses greater risk than jumping at 16" USDAA Performance... sort of what most of us have already concluded ourselves.
It would also suggest considering moving to Performance/Preferred sooner than later once a dog has reached a certain age or other stage such as say your dog having gained weight later in life.

 

[3Stars]

I also read from this that this research acknowledges that asking a dog to jump higher adds greater stress and increases risks to long term health.
e.g. asking a 16.5" sheltie to jump 22" in USDAA Championship poses greater risk than jumping at 16" USDAA Performance... sort of what most of us have already concluded ourselves.
It would also suggest considering moving to Performance/Preferred sooner than later once a dog has reached a certain age or other stage such as say your dog having gained weight later in life.

I agree 100%.

 

[Justicemom]

Interesting. So less than 2.5 height/weight ratio is better. Gawd, Koji's about 1:1. And also length of leg is important too. Koji has length, but maybe a bit too much. He'd probably be a lot better if his structure was correct. However, the art of sleeping doesn't seem to care about height/weight/leg length

That was interesting I will need to read it in detail later.

I found the ratio interesting. Ember is 0.9 Diva 1.4, Justice 1.2 and Birch is 1.64. Birch is on the edge of being too heavy right now. Ember, I consider very light boned, Justice light bone and Diva light to moderate Birch-moderate

Justice is my worse jumpers, Diva is my best, Birch and Ember, a close second. Diva is slightly long body and could have longer legs. But she is quick on her feet and has dual suspension I swear(can go anywhere any time), she is truely agile, a natural jumper. She makes up for it with natural atheletic ability.

Birch has the best overall structure of all my dogs. He is effortless in his jumping. Whether doing agility or catching a frisbee. I do consider him moderate boned for a sheltie. Leo is actually heavier bone and about as heavy as we would go. But they are alot of shelties out there with a lot more. They sort of lumber around and seem to barely pick up their feet, hard to describe but when you see it you know. That kind of dog looks like they are throwing themselves over the jump.

I will say Ember makes the quickest turns and reacts the quickest of all my dogs. She has the most pure body control when jumping. When she wants to run she gets over those jumps as well as any dog. 4 weeks ago she accidental took a jump that the bar was left at 20" and she sailed over it and landed like a feather. Compared to her, Birch is a MAC truck.

 

[HopeShelties]

Looking at the pictures, I'd say Starr is a little heavier than Leo, but still fits moderate. He's not like the tank like heavy dogs that come to mind when I think of a heavy boned dog. Curious, what are his average yps in jumpers, and is it with weaves or without, as it makes a big difference. Here, USDAA dogs post better yps in jumpers than AKC dogs because the weaves add time.
Athena (light boned 13.25") .9, Aurora (light boned 13.75") 1, Lark (light boned, 13.5")1, Breeze (11mos puppy light boned 13.25") .9, Kai (longer back, more bone than the light boned dogs- moderate 14") 1.25, Ember (stands 16", light bone, all leg) 1.25, Roxas (16" same light bone all leg) 1.25, Sundari (Moderate, still plenty of leg 15.5") 1.3, Caleb (my heaviest boned dog, though still moderate 15.25" and not as talented as my other dogs) 1.56.
Caleb lacks the thoroughbred like build of my other dogs. The rest are light boned, lean, and have good leg for their height. He is a different build from them completely. While he is heavier than my others, he is still moderate. I have shown him in ukc conformation against dogs I truly consider heavy, and he is nothing compared to them. He's better angulated than any other dogs I have, except Sundari, but he also has a different mindset and drive level than the rest. He is my slowest sheltie, and stays now as he is 6 years old, and will be staying forever, but isn't one I run at trials.