Shoulder-in is by far one of the most important suppling and collecting exercises you can teach your horse. Francois Robichon de la Gueriniere (inventor of shoulder-in) said: "This lesson (on shoulder-in) produces so many good results at once that I regard it as the first and the last of all those which are given to the horse in order to make him develop complete suppleness and perfect freedom in all the parts of his body."
Nuno Oliveira: "I never begin the training of a horse by giving him a lesson other than the shoulder-in."

Gymnastic value of shoulder-in consists in placing a horse in such posture that in order for him to move freely he has to place more weight on his haunches especially inside leg and lighten his shoulders. His front legs will have to move with more amplitude and in a circular motion to avoid hitting each other thus developing shoulder mobility. Shoulder-in develops grace, suppleness and collection in a horse and gives rider better control with less aids. Click here to read one of my previous blogs. This will give you another perspective why shoulder-in is so important.

When your horse moves forward with regularity, freedom and basic balance and can execute correctly 10 m circle and a few steps of leg-yield in walk and trot it is time to introduce him to shoulder-in. The bend in shoulder-in is the same as for 10 m circle and the main difference between leg-yield and shoulder-in is the bend. This bend has to be even from the muzzle to the tail and should not be exaggerated otherwise the horse lose grace and ability to go forward. The basic angle for three-track shoulder-in is 33 degrees from the wall. Less than 33 creates shoulder-fore and more creates four-track shoulder-in which is what it's creator de la Gueriniere was teaching to his horses. The difference between shoulder-in and shoulder-out is only placement of the wall. If you ride shoulder-in in the open field there is no in or out.

Lets see what to look for in a well executed shoulder-in. In the picture Anky van Grunsven riding Nelson in shoulder-in in trot. I would like you to notice a few things about it:

• The uphill appearance of the whole horse
• Inside hind leg is stepping forward right under the body
• Absolutely even bend through the whole horse's body
• The horse's neck appears almost straight
• Look at the right front leg, it's height and amplitude of the movement
• The diagonal pairs move in harmony, legs in each pair are parallel to each other
• The movement gives impression of going forward, up and sideways
• Anky's hips and shoulders are aligned toward the inside together with the horse's body
• Her shoulders and hips are level
• Both of her hands are slightly to the inside making inside rein slightly open and outside rein close the the base of the neck
• Her upper arms are vertical, elbows by her sides, straight line from the bit to the elbow
• Her inside leg from the hip creates a pillar around which the horse's body is bent. Notice her thigh is rotated inside so much you cannot even see the knee behind the knee roll, the knee is pointed straight forward.
• The heel is just slightly lower than the toe, giving impression of a soft ankle, the foot is parallel to the horse's side. There is no chance for Anky hitting her horse accidentally with the spur. She has to rotate her foot out to apply it.
• She is nicely centered over her horse, seatbones loaded evenly, no leaning/collapsing right or left.
• Anky's overall posture on a horse is so balanced that if her horse disappears from under her (Mary Wanless imaginary tool) she will land on the ground on her feet and will look like an martial arts fighter in the default position.

Study the picture, imagine how would it feel to ride such shoulder-in and in the next blog we will start working on it.

Happy riding...