Riding requires both thinking and feeling in equal parts. A rider who thinks too much quickly becomes rigid in their body and mind, and a rider who doesn’t think enough suffers from a lack of purpose in each ride. The former can lead to such things as impossible expectations, frustrations from both parties and a mechanical outcome, while the latter can result in stagnation of progress, wishy-washy execution, or a loss of interest from both parties.
Feeling alone can get a horse and rider combination quite far, particularly if the rider also has good general horse and riding instincts, though sometimes there is a lack of understanding why some things work and why others don’t that can stall progress. Knowing that something doesn’t feel right is part of the equation, but understanding why it’s not right requires gathering of data, thinking, and often execution of logical experimentation.
I want to focus solely on the seatbones, but not for the purpose of explaining how to sit on the seatbones properly, how to use them, or how to shift your weight on them. Google will have to be your friend for that information at the moment. My concern here is for the horse, specifically diagnostic purposes.
So, now that you’re sitting correctly on your horse for some flatwork, you’ve checked that your pelvis is level and you’ve not got a collapsed hip – and you are otherwise level in your ears and shoulders, and your upper body (including head) and lower body are aligned in accordance with your travel – pay attention to your seatbones and compare how the horse feels under each one, first at a walk in a straight line (both directions), then on a circle (both directions), then at the trot etc…
If you have any natural inclination to feel your horse through your seatbones you will immediately feel that the horse does not move under those seatbones equally. And that the difference can change depending on gait or direction of travel, EVEN IF you as the rider remain perfectly positioned at all times.
Those who have spent a lifetime of working (and feeling) to make their horse/s symmetrical; equally strong, straight and supple on both sides will know that any unevenness in their seatbones is wholly their fault. The rest of us need to figure out if it’s us or the horse, or both. The easiest way to determine which situation we’re dealing with is to have a person of superior riding skills ride the horse and tell you what they feel. Secondarily, you can employ a skilled set of eyes on the ground to correct your overall position of any significant unevenness/lopsidedness, while you concentrate on how those changes affect the feel of the horse under your seatbones. If, after fixing your position, the horse feels the same under your seatbones then you can logically assume the horse has a larger issue than just an unbalanced/crooked rider.
Certainly an asymmetrical horse can displace a rider’s positioning, just as an asymmetrical rider can displace a horse’s way of going. If it’s relatively minor in either case, then simple corrections can be made in the moment to even things out. Even long defined habits that have created uneven muscling can result in an immediate change if for just one or two steps both parties get on the same page. Obviously, it takes time to correct musculature unevenness, but it starts with just one step in the right direction.
For diagnostic purposes, the seatbone bone with more feel/horse under it is the more dominant/stronger/deeper stepping corresponding hind leg and is often accompanied by the haunch being carried to one side (to the side of weakness-being pushed over that way by the stronger and deeper stepping leg). If you can’t really feel either hind leg under either seatbone, rest assured the horse is hollow and trailing those hind legs. Of course, being able to know if what you’re feeling is really the hind leg requires you to have had the experience of riding a horse in a good amount of engagement on a prior occasion so you can make that distinction.
The biggest worry is going to be the horse that is consistently stuck under one seatbone, regardless of changes in rider, rider position, direction of travel, gait, or correcting/straightening exercise for that individual is surely unsound.
There are other points of feel that can help you determine what’s going on with the horse, but let’s just start with one point of reference. I now challenge all of you to go out, feel your horse under your seatbones and think about what you’re feeling and what it means for the horse.
(Suggested reading – this is a very technical book that covers rider from head to toe with such topics covered as how children, adolescents and adults learn about movement, physiology of movement, stabilzation of the body, gaining independence of body parts, coordination of aids, problems/causes/corrections for such things as asymmetry, stiffness, pain etc… I also believe this comes in video for those who learn better through seeing/demonstration : Balance In Movement by Susanne von Dietze)