One of the most devastating injuries that can occur in racehorses is strain or tear of the superficial digital flexor (SDF) tendon of the front leg, known in lay terms as “bowed tendons”. Part of the function of this tendon is to absorb shock during exercise. Rehabilitation is key for recovery, but healing is slow and recurrence is common. Therefore, studies of rehabilitation of this injury in horses are critical.
SDF tendon strain in horses likely has a multi-factorial etiology. One cause may be that fatigue in the SDF muscle leads to decreased support, over-extension of the fetlock joint, and resultant tearing of the tendon.
A previous study, performed at the University of Minnesota, suggested that tendon strain may be the result of the SDF muscle’s low energy stores compared to other equine muscles,2 making SDF tendons more prone to fatigue and injury. Thus, if training programs are designed to increase resistance to fatigue, it is possible that this type of injury may be prevented.
In humans, one way to strengthen and improve muscle energy stores is through resistance training. Resistance training can be employed in horses through the use of underwater treadmills. This project is part of a larger study that compared the effect of
underwater treadmill exercise and land treadmill exercise on muscle characteristics and cardiovascular fitness. This project
studied effects of underwater training on muscle fiber size and type in horse muscle. The results from this study may help to develop rehabilitation programs for treatment or prevention of SDF tendon strain.