By Steve Fisch, DVM
Tendons and ligaments are the connections that hold bones in place and allow the muscles to create propulsion either forward, backward, up, down or sideways. Both tendons and ligaments are made of collagen fibers that are arranged lengthwise so they are capable of stretching. Collagen is a tough protein substance found in skin, tendons, ligaments, cartilage, bone and other connective tissues. Collagen allows tendons and ligaments to stretch and gives them their strength. Tendons and ligaments are similar in structure but tendons are generally more flexible and have more stretching capability. Tendons connect muscle to bone and ligaments connect bone to bone.
Tendon and ligament injuries are an important source of lameness in the performance horse and in barrel horses and racing Quarter Horses. Tendon and ligament injuries cause lost performance time and are a major source of economic loss in training days, veterinary bills and time spent treating the injury. Injuries to tendons and ligaments can quickly end an equine athlete’s career. Tendons and ligaments both have great stresses applied to them, whether it’s a racehorse running full steam at 55 mph with the horse’s entire weight on one leg at certain phases of the stride, or a barrel horse maneuvering with quick speed and repetitive motion through the cloverleaf pattern.
The softer and more yielding the racing or performing surface, the more stress is put on the tendons and ligaments. Harder, firmer surfaces put more stress on joints and bones. Therefore a balance between too soft and too hard of a surface must be found. Barrel horses and racing Quarter Horses perform on many types of surfaces around the country. Some tracks and arenas have surfaces that are far too hard. These surfaces may result in very fast speeds but those extremely hard surfaces probably also result in an over representation of bone and joint injuries. Breaking from the chute or starting gate or racing and running on loose or sandy surfaces can cause problems because of the need for traction when breaking or racing at the speeds needed to win. Loose footing lends itself to causing forelimb flexor tendon injuries along with muscle strains, back soreness and suspensory ligament injuries. Arena surfaces are safer when the proper balance has been found. It may seem safer for a barrel horse to compete in a deeper arena but my opinion is that the looser footing can cause the horse to stretch and tear tendons and ligaments as he fights for traction or attempts to bring it home with a burst of speed after the last barrel.
Along with providing the proper surfaces for the equine athlete to perform on, prevention of tendon and ligament injuries begins at birth. It is very important for foals to have the ability to run and play in the pasture as they mature. Horses that are allowed to exercise freely as young maturing horses tend to develop potentially stronger tendons and ligaments. The response of the body to the strength that is required to jump from side to side and race his friends as he grows up goes a long way toward preventing future injuries. This is a good reason to know where and how the horses you purchase as young prospects were raised. All other factors being equal, a yearling that was raised in a pasture that has other weanlings and yearlings to play with will develop stronger ligaments and tendons.
Prevention also includes a proper fitness and training program. Depending on the athlete’s job, the tendons and ligaments respond to training much like bones do. As long as they see the maximum amount of stress that would normally be applied during a competition for a brief period of time, the tendons and ligaments respond by increasing in tensile strength in a manner that will make them better able to handle the stress of competition. The athletes’ tendon and ligaments don’t have to see this amount of stress several times a week. A good training regimen allows for a brief period of near maximum output on a periodic basis while allowing ample time for recovery and repair.