This is an issue that has cropped up in several lessons recently, so I have been particularly aware of how we use and misuse the indirect inside rein in dressage. The indirect inside rein can manipulate both horses’ shoulders and haunches, whether intentionally or not. Just to clarify the aid I’m talking about, imagine a vector drawn from the bit along the line of the inside rein; when this vector passes through the horse’s body towards the opposite side, instead of straight back to the inside hind leg or towards the inside of the turn (which would be called a direct inside rein).

The effect on the shoulders is fairly predictable: on the positive side, it can help move the horse away from the inside shoulder, but on the negative side, this can end up with the horse falling out over the outside shoulder. With young horses that have a tendency to lean towards the inside shoulder on turns and circles, it can be a useful tool to establish the beginnings of bend and transfer of weight towards the outside shoulder. However, it should not be mistaken for actual bend, which involves curving the entire body of the horse, whereas the indirect inside rein creates more of a “folding” effect on just a few joints. Taken too far, the result is that the horse runs out over the outside shoulder, which becomes particularly noticeable when there is no wall on the outside to check this movement.

The situation with the haunches is more complex, because the indirect inside rein can actually cause two opposite reactions. Used at a shallower angle with little bend, the effect is generally to push the haunches away towards the outside, while used at a steeper angle with more bend, the effect can be to actually pull the haunches inward. Neither effect is desirable for circles, turns, or shoulders-in, so it has no lasting place in those exercises. However, on the positive side, the first effect can be useful in leg yielding; here we have little to no bend, and we desire the horse to move sideways by pushing the haunches away from the leg, which a little bit of indirect inside rein can assist. Used without enough outside rein, the shoulders fall out, leading to little or no crossing behind. Used too strongly in conjunction with the outside rein and the haunches are pushed over too far, causing haunches leading in the leg yield.

The second effect (haunches pulled in) can be somewhat useful in all of the haunches-in type lateral movements (travers, renvers, and half-pass) for obvious reasons. However, it is important to remember that lateral movements are bending exercises – as I discuss above, the indirect rein tends to fold the horse rather than bend it evenly – so it should be used with discretion. Too much indirect inside rein can also end up restricting the forward movement of the shoulders. In half-pass, for example, the horse may feel restricted from moving its shoulders on the diagonal path, and instead end up with haunches leading, or even not moving sideways at all but rather on a renvers path. More useful in these exercises is the indirect outside rein (a topic for another day!).

The bottom line is that the indirect inside rein is of limited usefulness for dressage. The effect on the shoulders is only useful with green horses learning to balance, and the effect on the haunches is detrimental to most exercises, though can be used carefully in leg-yields and haunches-in type movements.