Page 92 - Speedhorse September 2017

TIPS ON KEEPING RACEHORSES SOUND
Fitness training conducted gradually will allow the body to stimulate new and stronger body structures.
by Heather Smith Thomas
In order to run well and not suffer injury, a horse must be at peak condition and soundness. Keeping horses sound through training and a racing career
can be a challenge, but there are ways to help young horses become stronger and more physically fit and less likely to break down.
Bill Casner has been working with racehorses all his life, and keeping them sound has always been his passion. “This is something a person needs to start addressing early on when working with young horses. Fitness, whether we’re looking at tendons, ligaments, muscle or bone, must go through an evolving process. Trainers often have to walk a knife’s edge in their goal to move the horse forward in fitness without taking things too far and creating serious damage,” he says.
You are trying to build up strength and fitness rather than tearing the body down. For any body
part to become stronger, however, there must be some stress and strain. Body conditioning involves some type of strain to be placed on the muscles, bones, tendons, ligaments, heart and lungs. The process of body strengthening involves the creation of micro- damage, which occurs when stress is placed on certain body structures to create a small amount of damage and, as it heals and repairs itself, the body structure heals stronger than it originally was. “With bone, this process is called remodeling,” Casner says.
There are two types of bone cells—osteoclasts, that breakdown bone tissue; and osteoblasts, that build new bone. A study conducted at Texas A&M showed that when a horse is first put into training, the horse will lose bone in the first 60 days. “There is heightened osteoclastic activity. Remodeling is the perfect word to describe what happens with bone, because you have to tear something down before you can rebuild it,” he says.
It takes that much time to begin the process of building new bone and for the osteoblasts to engage
at a higher level than the osteoclasts. At roughly 120 days, the horse is back to where he was prior to train- ing. “You actually have 120 days in which the horse is extremely vulnerable to injury and the trainer needs to be aware of this,” Casner says. From that point for- ward, the horse must continue to build stronger bone.
Trainers walk a fine line in pushing for maxi- mum strength and fitness while avoiding injuries and breakdowns. The rate of bone remodeling is fastest in skeletal areas that have the most loading stress. Bones in the feet and legs receive the greatest loading stress while running and can be expected to undergo substantial remodeling during exercise training.
Studies have shown increases in density of the cannon bones and knee bones during training. This adaptation to the stress of training is crucial because bone density is an important determinant of bone strength. The intensity of training, however, has an important bearing on this response. Low intensity exercise, such as trotting, results in minimal changes in density of the cannon bone, whereas training at higher speeds, such as galloping exercises, results in a more noticeable increase in bone density. Intense exer- cise is necessary to produce a beneficial response in bone. The challenge is in choosing a training program that is sufficiently intense to produce a beneficial response in bone, but does not overload the bone and other supporting structures. Rapid increases in train- ing load over a short period of time often will result
in an injury such as fractures, strains of ligaments and tendons, etc.
STARTING EARLY
“Fitness training begins on the day we start break- ing these young horses when we put a saddle on their back and subject them to stresses they are not used to, and which we must adapt them to,” says Casner.
Heather Smith Thomas
90 SPEEDHORSE, September 2017
EQUINE HEALTH