In a perfect world the horse is connected to us through the reins, meaning that the contact we’ve established on the reins serves as the ultimate communication tool. There is no tension, simply touch and with it the power to execute energy through the horse at a moments notice.
What this means for us as riders is that the legs become quiet and are used primarily as a balance point, but please don’t misunderstand and think I mean balance through squeezing or holding on with the legs. There is a large issue of overusing the legs as it compromises your balance, creates tension upwards into your seat, can radiate into your hands and promote pulling on the reins not to mention add confusion and complication to your communication with the horse. The less that we have to use in order to let the horse know what we want, the better.
Contact on the reins can only be appropriate if the horse is pushing/propelling himself forward from the hind legs calmly, while also maintaining the proper bend. Without these our ability to communicate through the reins is compromised at best, though often worse – disconnected.
The magic happens quite brilliantly however when these elements are all in concert with one another, as you can orchestrate collection in the horse, gait transitions and spectacular lateral work that is forward, light and graceful primarily through the reins. The legs working secondary to the hand in providing support. On the other hand, to rely upon the legs primarily the hands are left to working in excess to either contain the anxious energy created by the overuse of the legs and force position to create second rate lateral work and dull transitions.