Introducing 

Prezi AI.

Your new presentation assistant.

Refine, enhance, and tailor your content, source relevant images, and edit visuals quicker than ever before.

Loading…
Transcript

Another important concept related to center of mass is base of support, or every point of contact an object has with the stabilizing surface beneath it. For a person standing on the ground, his feet are his bases of support. If he lifts one foot, then he has one base of support. Conversely, if he gets on his hands and knees, he has four.

The center of mass of a horse is just below it's withers (where its neck meets its back) and behind the girth (the front elbows)

Center of mass is important to:

  • how and where a riders should sit
  • the placements of the saddle on the horses back
  • how to attach a cart correctly
  • balancing while racing, jumping and other equestrian sports

A stationary horse has a rectangular shaped base of support - it is very stable while standing still. The faster a horse moves, the fewer hooves there are on the ground at a time and so the horse must rely more on momentum to move it forward. A slow moving horse cannot rely on momentum as much and relies more instead on keeping the most hooves on the ground as possible - thus enlarging its base of support.

The center of mass of a horse moves forward slightly as it increases speed since it puts more weight onto its forehand.

Collected vs extended gaits:

A horse moving in a collected gait it puts more of its weight onto his hind and "collects" itself up, raising its back. It results in the slight shift of center of mass back as compared to an extended, or entirely forward, gait. (Photo courtesy of Riding Art, "A Horse's Balance")

Horses generally move on the forehand so their center of mass is not located in the exact center of their bodies, or the center of the rectangle of bases of support. Instead, it is shifted forward slightly. A rider seated behind the horses natural center of mass shifts the center of mass back towards the horse's center due to the added weight. The rider also has a center of mass - usually a bit below the belly button for humans. Because of this high center of gravity, the rider can easily unbalance the horse and themselves - as many new riders find out. Leaning forward, lying back, shifting side to side all can affects the horse's center of mass.

Canter Piroutte

A canter piroutte is a technique in which a horse turns about its hind legs at the canter while remaining almost entirely in place, as seen in the video below.

The movement requires the horse to collect itself with its hind legs underneath it, thereby shifting its center of mass back from its natural position. A canter pirouette is very difficult skill because it requires a great deal of balance for a horse to move in a stationary circle.

Piaffe

A piaffe is a highly collected trot in place. In order to do this properly, the horse must collect itself on its hind end, much like with the center pirouette. Dressage has many requirements of the correct piaffe, most important of which is that the horse is balanced and the movements collected.

Center of Mass: Horses

Balancing!

My previous two RWAs focused on the physics of riding and exercising horses. This one will keep to that theme! The goal of this RWA will be to examine how horses balance.

After working with horses for years and now taking this class, I've come to wonder how exactly they balance. Of course it's necessary for all animals to have mechanisms for balance. Horses have the added task of balancing with riders on their backs, while sailing over jumps and as they pull carts and plows behind them. How do they stay balanced in each? What mechanisms of physics and biology come into play to keep them balanced?

CENTER OF MASS

An important part of balancing for any animal is the concept center of mass.

Center of mass in horses

Center of Mass = the point on an object in which the mass of the object is concentrated

Center of mass and movement: Dynamic Balance

Since no one gets on a horse just to stand around!

Balance and movement

The center of mass of a horse changes as it moves, especially as it changes gaits (walk, trot, canter and gallop). The pattern of a horses movement (which feet are on the ground when and in what combination) changes with each gait. The figure on the right shows a horse's base of support during the walk, trot and canter. Since it changes, the center of mass must change as well!

Jumping

Image courtesy of Clayton "Balance Basics," Veterinary Connection

Center of mass in stages:

White "X's" = the natural center of mass.

Red "X's" = the shifted center of mass

1) The approach.

As the horse approaches the jump, it places all four hooves and lowers its center of mass by lowering its head and neck.

2) The takeoff: period of time when front legs leave the ground until back legs leave the ground

In order to maximize jumping height, the horse "collects" its legs underneath itself thus centering its balance more in its center.

3) Flight: period in which the horse is in the air. During this time, the horse's center of mass moves like a parabola over the jump

4) Landing.

When the horse lands, its center of mass shifts forward entirely to its forehand. The rider, if pitched forward, can further cause the center of mass to move forward and unbalance the horse.

5) Re-balancing.

Once all of the horses hooves are on the ground the horse re-balances and its center of mass returns to its original position

Center of Mass with a rider

Now let's look at more complicated movements of a horse and try to determine the center of mass.

Racing

Photo courtesy of Indiana's Equine Sports Message and Rehab Center

In racing, a jockey leans forward in order to shift his center of mass in the direction of the horse's movement. In doing this, he reduces the weight on the horses back.

  • jumping
  • racing
  • dressage

* the blue "X" shows the jockey's center of mass

Dressage

Works Cited

Dressage is a competitive sport in which a horse and rider pair preform a routine of specific movements much like a dance. It requires the horse to maintain balance while performing difficult techniques, two of the more challenging being the piaffe and the canter pirouette.

Clayton, Hilary. "Balance Basics." Veterinary Connection (2005): 19-30. USDF Connection. Michigan State

University College of Veterinary Medicine, Apr. 2005. Web.

Dausend, Tonja. "The Horse's Balance." The Horse's Balance. N.p., 2005. Web. 27 May 2014.

The white "s" is the horse's natural center of mass. The red "x" is the horse's center of mass during a canter pirouette

Video courtesy of youtube "Blue Horse Matine"

Learn more about creating dynamic, engaging presentations with Prezi