Seat generally covers two areas of riding.  The first, and most basic, is the rider's position and stability in the saddle.  Second, and impossible to achieve without the first, is the rider's ability to effectively use the aid known as seat.

In this e-lesson, we are going to explore the first area - the rider's position and stability in the saddle.  In times past, riders developed a seat before they were ever allowed to take responsibility for directing and controlling a horse.  Novice riders were instructed on experienced and well-trained longe horses by instructors highly skilled in the art of longeing.  Unfortunately, in this day and age, longeing skills, for people and horses alike, often do not extend much beyond the concept of running around in something vaguely resembling a circle at the end of the longe line without either pulling the person in the middle off their feet or running them over.  This makes the quiet, forgiving school horse invaluable since most people have to learn "on the fly", as it were.

Seat is composed of three elements: Grip, balance and suppleness.  We'll take each one individually.

Balance:
Balance is the rider's equilibrium in the saddle.  Balance keeps you upright when you stand or move.  On the horse it tells you that you are "centered" on the horse both laterally (side to side) and longitudinally (front to back).

Suppleness:
Suppleness is the rider's ability to follow the movements of the horse without losing balance.  Suppleness finds its essence in relaxed and moveable joints.

Grip:
Grip is used (judiciously) to maintain the rider's balanced and supple position and (more forcefully) when balance and suppleness are lost.  The only grip employed should be executed by the inner thigh between the knee and hip.  There is no knee grip (and definately no calf grip!) in riding -- only inner thigh grip.

In order to be balanced the rider needs to "stack" the parts of his or her body in a vertical, stable column.  A properly positioned rider will have an imaginary line passing through the ear, the shoulder, the hip and the center of the ankle.  If one could magically remove the horse from under the rider like the magician takes the tablecloth from under the dishes on the table, the rider should land balanced on his or her feet.  The spine should be straight, neither rounded nor arched and the rider's weight should be resting on the center of the seatbones, not tipped to the front or back.

The leg should lie flat against the horse's side with the inside of the thigh and the inside of the calf (not the back) maintaining a contact without "clutching".  If the back seams of your boots are showing wear, you're doing it wrong.

The upper arms should lie flat against the rider's sides dropping vertically from the shoulder with the elbows resting at the waist, just above the hip.  An imaginary line should pass through the lower arm from the bit, through the rein, through the wrist and to the elbow.  This line should be maintained both from the side and from the top.  There should be no break in the wrists, either side to side or up and down.  The feel should be very much the same as it would be if you were carrying a tray of drinks.  The orientation of the hands (thumbs on top) is also the same.

The stirrups are not a balancing aid, merely a place to rest the foot, thereby taking some of the stress off the hip joint.  The foot should rest squarely on the tread, not diagonally across and be against the inside of the stirrup, not the outside.  The weight should come down square and straight through the ankles to the heels with no break in or out in the ankles.  How much weight should you put in your heels?  The correct answer -- none!  The stirrup supports your foot and a supple, relaxed ankle allows the weight of your leg to settle in your heel.  The saddle supports the weight of anything at the level of the seat of the saddle and above.  The stirrups support only the part of your body below the level of the seat.  Pressing weight into the heel only steals weight from the seat of the saddle, making you "float" above the saddle.  A longer leg (probably the goal of every conscientious rider) is achieved, not by lengthening the stirrups, but by riding without them and relaxing the hip joint to allow the leg to drop from the hip.  Lengthening the stirrups will only cause the rider to "reach" for them, thereby standing on the balls of the feet which causes the rider to tighten the quad muscles and force the leg out of its proper position.

In the beginning, and even later on, the rider can't always trust that what they feel is totally valid.  We've all seen or experienced how a rider can be "miscalibrated", so to speak.  The rider who constantly tenses forward will probably feel as if she's leaning excessively backwards when she's barely achieved vertical.  The rider who always slumps his shoulders will feel stiffly arched when, in fact, he's finally sitting upright.  That is why we all need "eyes on the ground" in the form of an instructor of some sort so we can make sure we stay "calibrated".

The rider who can maintain the proper postion in the saddle without undo effort at all three gaits will be able to apply the aids in a clear and unambigious fashion and will also be able to "hear" his horse clearly.  That's called communication and, ultimately, that's what it's all about.