The classic way to develop a steady, independent seat is to work without stirrups. Exercises performed on the longe line without stirrups and reins are even better.
Not everyone, however, has access to a reliable horse for longeing or a skilled helper at the center of the circle. Many riders aren’t comfortable working without stirrups if their horse tends to shy or if the horse is feeling fresh.
One solution is to combine the classic long-and-low exercise (often called the ”stretchy-chewy exercise”) with sitting trot instead of the usual posting trot. While sitting to an active, swinging trot, the rider softens her hands forward, and the horse should follow the release by stretching his nose out and down toward the bit, chewing the bit softly while doing so. Although the horse’s neck goes lower, his shoulders should still remain up.
This exercise is done ideally at the end of the training session so that the horse is well warmed up and swinging through his back. The rider is also less likely to be stiff and to bounce. The rider will finish with a posting trot long-and-low so the horse can loosen up his back again.
One thing the rider learns here is whether she’s relying on her hands for her own balance if she has trouble staying upright when she releases the reins. When that happens during this exercise, the horse won’t be able to maintain the stretch but will raise his head and drop his back. Or he may just slow down.
The prerequisite here is that the horse has been taught to respond to the release of the reins by stretching out and down to seek the bit. The horse shouldn’t duck his nose to his chest. However, if he stretches so low that his nose reaches near his knee level, then he’ll start to curl back a little more to avoid coming too much on his forehand. The rider shouldn’t request the stretch by making the hands more active or by dropping the reins but by encouraging the horse to seek the bit through gradually releasing the reins.
The effect of this exercise is similar to work on the longe because the rider can’t balance off the reins. If a rider isn’t used to doing a lot of sitting trot, a couple of 20-meter circles will be enough the first time because the trot strides will be active. When she does this at the end of each riding session, she’ll be able to build up the time as her stability and strength improve. The rider will want to spend an equal time in each direction on a 20-meter circle.
One variation of the exercise is to do serpentines, scissoring the legs (the new inside leg forward and the new outside leg back) at each change of direction without losing any stability in the saddle.