HARD TRAINING BEFORE PHYSICAL MATURITY
One of the smartest moves you can make early in your horse’s athletic career is going slow. An immature horse’s cartilage is still forming and not able to withstand hard or repetitive work. It is more likely to be damaged and less likely to be able to heal itself, leading to the development of early, and possibly severe, arthritis.
How soon a young horse can handle training depends largely on his breed: Warmbloods need more time to mature, while Quarter Horses may be ready sooner. There is also individual variation, so a youngster who doesn’t look as physically mature as his peers probably isn’t. When you do put a young horse into work, take it slowly. Keep in mind that torque (twisting force) is particularly tough on joints, so limit the amount of work done in small circles or with tight turns and resist the urge to drill new skills repetitively. Also, be sure to incorporate plenty of rest days.
Finally, set aside competitive goals if your young horse doesn’t seem to be adapting well to the work. Putting off a show or two now is a small price to pay for soundness in the years to come.