Why Do We Mount From the Left?

Bronzz's and my favorite mounting block, an overturned stock tank with steps.

Xenophon gives the earliest answer still in print in “The Art of Horsemanship” (circa 350 B.C.) It has to do with the hand in which you hold your spear. You might even use your spear to vault onto your horse. However, he strongly recommends learning to mount from both sides, so you are always prepared for battle. Apparently the rigid rule that we must mount from the left came later when cavalry officers wore a sword on the left, and it was safer to swing the right leg over the horse. So here we are with neither spears nor swords, just a tradition whose reason expired long ago. Is there any reason to change it?

Hauling on saddle with 2 hands. Shiloh is NOT happy!

There are two excellent reasons to re-think how we mount.
(1) The horse’s spine is stressed as the rider’s weight pulls on it. Shiloh's heads-up tension shows in this photo as her rider's weight drags on her saddle. A slow motion video shows the twist from behind as a small, skilled rider mounts. Play Video
(2) Mounting builds one-sided muscles in both horses and people, as you will notice if you try mounting from the off (right) side.

Left hand on mane, right on front of saddle, weight over saddle. Shiloh is relaxed!

To minimize stress on your horse’s back:
(1)Hold mane with your left hand and front of the saddle with your right. Both hands on the saddle causes more pull on the horse’s spine as the saddle slips and/or twists.
(2)Jump your weight over the horse’s back and lean on your hands while swinging your leg over (previous photo), to avoid hanging off the horse’s side.
(3)Sit down gently, as if sitting on eggs.
Careful mounting is not only better for your horse’s orthopedic health, it is considerate. Horses do notice such courtesies, as shown by the fact that they work better for considerate riders, independent of skill level. My book What Horses Really Want includes a chapter on Being a Considerate Rider: 13 ways to become a rider horses want to carry.

Mounting from a tree stump with door mat tacked on for traction.

Solutions:
Though it’s good to be to able to mount from the ground when necessary, there is no need to prove it every time. It’s more important to be considerate of your horse. Here are some options:
(1)Use a mounting block, stool, tree stump, overturned stock tank, or anything else for a height advantage. On trails, look for a log or rock, or stand the horse in a ditch or downhill from you.
(2)Have someone hold the off-side stirrup leather or fender to keep the saddle from slipping.
(3)Alternate mounting from both sides, preferably with a mounting block. Once a horse is comfortable being handled from both sides, all he needs is warning to brace himself the opposite way. Horses generally adapt much quicker than people do.
(4)Get a leg up.