One of the most common questions people ask is: am I too big for my horse? The size of the horse should be proportional to the rider, but weight alone is not the only factor to consider. Height and riding skill come into play when it comes to making the horse's job easier and the rider feel secure and comfortable. So, in some cases, a smaller horse will do just fine with a heavier rider. Conversely, a smaller but less skilled rider can be more difficult to carry for a larger horse, make a larger horse's back sore and create leg soundness problems.
One factor that influences how easily a horse can carry a rider that may be almost as important as weight, is the rider's skill. A rider who is balanced in the saddle and has a good seat will be easier for the horse to carry than a rider who is sloppy in the saddle. If you've had the experience of carrying a child while it is awake, and then while it's asleep, you'll know what a horse feels like when carrying a rider who holds itself up, compared to a rider who is loose and unbalanced.
It won't take long before a horse who must carry an unbalanced rider will develop back and soundness problems that can also lead to behavior problems. Improving your riding skills not only makes your ride more comfortable, safe and secure, your horse will also be more comfortable, sure-footed and stay sound much longer. Make an effort to improve your riding skill by taking lessons and paying attention to equitation when you ride.
When people wonder if they're too heavy for their horse, their main concern is weight. A recent study, published in the Journal of Veterinary Behaviour, suggests that the rider should weigh less than 15% of their horse's body weight. This means a 1500-pound horse should be able to carry a rider of 150 lbs or less.
Traditionally, the general guideline has been a horse should carry less than 20% of its body weight. This may be too heavy. And, as the study revealed, about 30% of us are too heavy for our horses.
When a horse is very young, with developing joints and bones and when a horse reaches its senior years and begins to become arthritic, it's time to lighten the load. The overall workload of these horses needs to be lighter—in weight, time and intensity, than a fit horse in the prime of its life.
Height is another factor that impacts a rider's security in the saddle. If you are tall, you may feel very top heavy on a shorter horse with fine bones. A solidly built horse, such as an Icelandic, or Fjiord might be more comfortable, even though it is short in relation to many other breeds like Arabians and Thoroughbreds. Anything that makes you unbalanced will make it harder for your horse to carry you.
The Bottom Line
When you are selecting a horse, try many different sizes out. If you're on the heavier side, as many of us are, consider a breed like a foundation type American Quarter Horse or a draft or draft cross.
If you're slender, then an Arabian or Thoroughbred might be ideal. If you have your heart set on something like an Arabian, look for a horse with thicker bone. Bone is measured at mid-canon on the front leg. The higher the circumference, the more sturdy the horse is. On Arabian, eight-inch bone is considered quite sturdy. With the right match, both you and your horse will be more comfortable and less stressed.