From here on, the trajectory of the center of mass is a parabola and the horse has no control over the movement or its angular momentum. It can only shift the position of its body and legs relative to the center of mass. Note how much the flexed hind legs have straightened. This is the end of that particular Muybridge sequence. The jump continues with a different set of photographs of the same horse and rider, but the transition between the the last photo above and the first photo in the next series shows some differences in the placing of the legs and the degree to which the body has rotated back to the horizontal.
Forelegs begin to drop and reach forward for the landing after clearing the jump.
Hind legs are beginning to tuck in order to clear the jump. Note that the rotation of the body puts the shoulders high at the time the front end is over the jump, and the hindquarters high at the time the rear legs are over the jump. Continued downward and forward reach of forlegs, continued rotation of body and tuckup of rear hooves to get them as high as possible relative to the center of mass. Rear hooves clear this rather low jump just as the non-lead front leg starts to touch down. Note the extreme flexion of the pastern on the landing leg.