The head position and emphasis on the round neck is a pretty recent obsession for riders, probably of the past 50-60 years. I might be wrong on the dates, but I know for sure that it didn’t use to be such a big thing before our time. We see it all the time today, riders using their hands to bring the head down (even with light hands), riders using draw reins, or lunging equipement that put the head of the horse in a position that rounds the neck.
But this head position, the one we see in old drawings, used to be a consequence of good self carriage of the horse, the sign of good classical training by a talented and rigorous rider. So before I go into why it’s not a good idea to focus on the head, I’m going to talk a little bit about classical riding and the head position that follows, as a consequence.
This is my take on good classical training: the aim is to get a horse that is straighter, stronger and more supple. To acheive this, there’s exercices that were developped because people noticed that moving the shoulders of the horse in a certain way made him more straight and more forward after. Shoulder-in, hanches in and lateral work are all exercices than you can use to help your horse be more supple and more straight. You teach them from the ground, and once the horse is comfortable and fluid in the movement, you can transfer it to ridden work. But the aim isn’t to do it because it looks pretty, the aim is to have a positive impact on how the horse moves.
Because developping a horse by using those movements help stimulate different muscles, different fascia, it helps release tension in the body and coordinates the legs, it helps supple the back and engages the core. All the things that, I’m sure, you know you should try to do.
So that’s the aim of basic classical training. The consequence of that is a change in posture. Have you ever noticed that you sit differently after a work out? Or after a yoga lesson? Your posture is influenced by your physical activity. So with the right exercices, we see a change in the posture of the horse: the back is more supple, the shoulders are free, the hips are loose, the withers are lifted, and as a consequence of all those things, the balance of the neck is modified. Because the withers and shoulders are more free, straighter and stronger, the neck comes out of the shoulders in a different angle, with the neck rounding more with increased strenght and balance. It’s a consequence of everything else that is going on in the body of the horse. And the more balanced, supple, strong and straight the horse is, the more self carriage the horse developps, and the more you will see the neck going round. That’s what the neck position is about, true self carriage that starts from the hind, goes all the way through the core muscles of the horse into the shoulders to finish in the neck.
Now, if you understand that, I’m hoping you’re able to see why forcing the head and neck in a position is conter productive. So let’s have a look.
From a riding point of view, forcing the head down, weather it is with your hands, with the help of draw reins or other artificial aids, doesn’t acheive self carriage of your horse. I hope that you got the idea from the paragraph above, that self carriage starts with the movement of the back and of the legs.If you start by shortening the neck, you’re starting from the wrong end of the story!
Bringing the head down has all sorts of consequences:
– it shortens the neck and, because they are all linked, the vertebral joints along the spine. This means that you are creating a wall and pushing your horse into it. That’s the way I picture it in my head anyway 
– it prevents the withers from lifting and the back from fully working in a relaxed manner. In this position, the back is maintained slightly hollow and short, with the topline muscles contracted short. But to acheive self carriage, you need the topline muscles to be relaxed and longer, in order to lift the withers with the help of the abdominal muscles!
– It brings the weight on the forehand and the horse, instead of carrying himself from behind, falls between his shoulders. once again, this prevents the withers from lifting, the shoulders aren’t free to move anymore and the angle between the last cervical and the first thoracic becomes sharper.
– it reduces the movement of the hind legs. It’s been proven in dissections that if you fix the TMJ like you would when riding with too much hands, the movement of the hind leg is grealty reduced. So you actually loose hind end impulsion when you ask your horse to lower his head.
My advice to everyone would be to keep the hands still as much as possible. With still hands, you can make your communication with your horse a lot more clear, avoiding all confusion as to what you’re asking; you can also maintain and work on your contact with the mouth. Finally, with still hands, your horse can express how he/she would carry himself/herself in this moment, which gives you a great feedback as to how your horse is feeling in the back, in the neck, and can give you ideas to try different exercices to help supple and strenghten the entire body!