If horse movements were the letters in the alphabet, the "stretch" would be the letter E. Statistically, the letter E shows up more frequently in words of the English language than any other letter. You can find the letter E in every part of the word - from the beginning, to the middle, or even at the end. And so should the stretch be incorporated in exactly the same way during your rides.
If you are a yoga aficionado, you might relate better to thinking of the (horse) stretch over the topline as a sort of moving savasana - after completing a series of movements requiring contractions and releases (collection and extension), allow the horse to just "let go" for a few minutes, whether in walk, trot or canter, using the savasana-like stretch over the topline.
But don't just let the reins go to the buckle and become a blob on your horse's back. There is a real art to stretching the horse so that it is beneficial for him. If you just let the reins go, the horse has nothing to reach for and gets longer and longer (disengaged in the hind end), heavier and heavier (on the forehand) and hollower and hollower (over the back exactly where your weight is).
This sort-of stretch is not only counterproductive to the development of your horse's muscles, but also teaches him that he can't rely on you to be his partner in movement. If you drop him, he learns to drop you.
So what's the alternative? Here are the aids to develop a functional (or effective) stretch over the top line. You can stretch at any gait assuming that the horse doesn't just speed up and "run away". The stretch is most useful for encouraging the horse to release the muscles especially over the back and under the saddle.
1. Take Contact
Just be careful to not actually pull back. There is a difference between shortening the reins and feeling the horse's mouth, and pulling backwards on the rein. If you notice your elbows going further back than your torso, you are pulling too much. Just shorten the reins until you feel the pressure, and stay there.
2. Use Seat and Legs
This part is the the "ask" for the stretch. Use two legs together to engage the hind end. Immediately after that, the seat initiates and encourages the stretch by scooping up and forward to the front of the saddle. You can also lighten your seat - not by tilting your body forward (as in two point), but by just becoming lighter in the saddle.
Up till now, you still have the same level of contact that you established in part 1.
3. Allow the Horse to Pull the Reins Out of Your Hands
This is where things get tricky. Most people want to just throw the reins forward toward the horse's mouth. If you've ever tried it yourself, you'll know how it feels when something is just let go. Instead, you should wait for a few strides.
Once your horse takes pressure on the rein, you can let the reins out a tiny bit at a time. Even now, don't just throw the reins at the horse. Have a soft, marshmallow feel to the reins and let him take the reins out of your hands.
4. Stretch Forward and Down
This is critical. The whole point of the stretch is to elasticize the topline. To do that, the neck must move forward (to stretch the topline muscles) and down (to reach the muscles behind the wither area). So lengthening the neck straight ahead at the normal head height does not qualify for a stretch.
Of course, lengthening the neck up to the sky isn't the answer either, because the muscles behind the withers are not stretched and probably must even contract. There should be a round arc in the neck and steady contact to make it an active stretch.
5. Take the Nose Forward and Out
The key to the stretch is for the horse to take the nose forward and out at the bottom of the stretch. It shows a softness in the poll area and ensures that the stretch occurs "from the nose to the tail". If your horse stretches forward and down but keeps his head tucked under, don't worry too much but lightly push the reins forward to encourage him to take the nose forward.
Just keep that steady contact and wait for him to learn to take the reins forward even in that position. Keep asking with your aids (#2) and calmly and steadily wait with the contact. Let the reins out at the first hint of pressure from your horse.
What if your horse doesn't take the reins?
This happens all the time, especially for horses that are not used to stretching, or for riders who are new to it. There is nothing else to do - you can't take more pressure, kick more, lean forward, or get agitated. The only suggestion I have is to wait. Re-establish your contact, ask with your aids again (#2) and wait.
Look for any movement in the right direction. If your horse even thinks about taking the reins out of your hands, lighten your fingers - but don't throw the reins forward - and patiently wait for him to take the reins from you. It will come in time.
Incorporate the stretch at the beginning of your ride to loosen up his topline and set a calm, elastic frame of mind. Use the stretch at the end of the ride to "shake out" the muscles. Use it through your ride to reestablish a soft, swinging topline.
Once your horse discovers the stretch, he might want it periodically through your rides. Listen carefully and use the stretch like you'd use the letter E - all the time!
Finally! The Ultimate Rider-Centered Program!
