With the excitement of jumping, both horse and rider sometimes have trouble waiting for the jump to come to them! When horses rush, change their rhythm or stride length, or brace against the rider’s hand, their balance will usually be negatively affected.
"Take your time that your horse is more relaxed, then he can really collect." ~ Johan Hamminga
Varying the degree of your half pass can improve your horse’s suppleness from all angles, as well as increasing his responsiveness to your aids within the movement. In other words, while going in half pass across the diagonal, half halt, and do a few strides with a steeper angle
"The better the rider’s balance in the saddle, the better the communication. There are two things the rider must be – balanced, and supple. The less good the rider’s seat, then the more often the rider is in the saddlery shop buying new saddles, new stirrups. The rider
"Through the energy of impulsion mobilized from within himself, the horse is now prepared, in his physique and emotional attentiveness, to respond instantly to the slightest indications to change his tempo, posture, direction or gait." ~ Waldemar Seunig