pressure and mocap must serves as a reader for the rider in order to modify/adjust body patterns. In other words, imagine that your phisical pressions ride (and control) the horse, that is. No reins, no spurs, even no saddle.
On the other hand there is a pearson (the rider) who can get any... disability (well, that's the "usual" used word to define it, but I'm not sure about the meaning of it and I don't like to use it, but that's another question). Anyway, we must read how he/she is developing the aptitudes, and moreover, how to act to perform any action to the horse, that's why use Opensim. We can work all this data "offline", but the best is on real time as you can see directly what it happens.