Join Date: Oct 2007
Location: Alberta, Canada
• Horses: 0
Alright, I'm on my laptop here.
Drifting is caused by the rider thinking that the horse will follow the rein aid anywhere - this isn't the case. If you only have control of the head, you don't have control of the horse. You can pull on the left rein all you want, and the horse can pop his shoulder right and go in that direction, and vice versa. To have control of the horse, you must have control of the haunches, ribcage and shoulder - the head can do whatever it wants as long as you have the other three elements; but, as we all know, when the horse is round and supple, the head naturally falls in place - that's why I'm saying don't worry about it.
To gain control of the shoulder, I would recommend lots of lateral work on the flat - you must learn, and teach him, that your leg aid not only can mean "speed up" but also "move away from this" or "pick this up" or "lengthen" or "collect." Some exercises I would recommend are: Turn on the forehand and haunches (true turns around each, not what I like to call "spinning around the middle" where the horse kinda moves around a point, but not really), shoulder-in, haunches in, and bending and counterbending on the straight and on a circle.
Once you have control of the shoulder and haunches, you want to anticipate the drift and correct for it with the leg that he's drifting into, either with a shoulder-in type of cue, or even a slight counterbend.
The lovely images above provided by CVLC Photography cvlphotography.com