The rider, to ride well must be supple; the body must be filled with shock absorbers at every joint to allow the movement of the horse to go through the legs and up the rider's spine without getting stopped anywhere. For the dressage or western rider the ankles, hips and shoulders must be relaxed, moveable, and independent of the movement of the torso.

This disassociation allows light, precise use of the legs and arms for aids. When jumping or standing in the stirrups the legs help the rider maintain balance and the joints act as shock absorbers and stabilizers. The legs are not disassociated but part of the balance system. Still, they must absorb shock. When we tense up we interfere with our horse's balance and cause resistance. We also lose the capacity of our body to dissipate the energy coming from the horse so we take more impact, and want to tense more. It’s a vicious cycle. There are many chapters and whole books on this concept of the balanced, supple rider, yet we continue to read outdated fitness ideas that strength and tension will help the rider sit better. For example, a quick preview of recent articles:

Pinch your shoulder blades together and push them down...
Strong abdominal muscles are necessary to sit the trot...
Strengthening your legs will keep them longer and more relaxed....
Tense shoulder means that they are weak...

And the solution is to strengthen some body part. This advice invites and perpetuates riders tensing up against the movement of the horse rather than using the body’s capacity to dissipate energy and absorb shock—and move with the horse. From research and experience I know that too much of fitness advice is ill-concieved, counter-productive, and a waste of time.

I think I'm right about this even though it goes against the mainstream thought. I'm also constantly trying to figure out if my idea of right is truly right. And there is a paucity of research on what it takes to sit on a horse and move with it without disrupting its balance while directing the movement. The targeted strength training for fitness doesn't add up when we watch for example, small riders, riding with a very balanced seat, fluently moving with the horse, and seemingly using no strength or force, or when we watch children, relaxed, upright, and smiling on their ponies. I have experience of my own riding and teaching seat lessons and a long history of exercise, injury recovery, more exercise, et cetera—until I began working with movement, awareness, and motor control through the work of Moshe Feldenkrais and gave up strength training I couldn't sit the trot.
The logic of the mainstream, depending on what you read, is that pain or injury are indicative of weakness and tense areas also shows signs of weakness so something needs to be strengthened, or that tense parts are too strong so the opposing muscles need to be strengthened--and all too often on weight machines--which do nothing for motor control or dynamic stability.

So what is the answer? How do we learn to stop tensing and start moving, allowing the force to dissipate so we can ride in comfort?

Learn to breathe into your lower belly. This is the first step on coordinating the movement of the lower pelvis. Chest breathers elicit tension and work on the edge of fear. Tandian breathing, taught by martial arts masters, keeps your nervous system calm and movement balanced and coordinated.

Learn Tummy-Out! or Abdominal Bracing—the opposite of zipping-up or abdominal hollowing the nemesis of good movement and lumbar spine health.

Sit in the middle of your horse, in balance. If you sit a bit off to the side you'll likely tense somewhere to maintain balance.

Think endurance, supple motor control, coordination, and awareness rather than strength. After all, you’re not planning to pick up that horse, are you?