The German regulations give the same instructions as the Austrian. (See also paragraph 247, U. S. Cavalry Drill Regulations.)
When the stirrups are too long, the rider is said to be on his crotch (fork seat); he loses all stability; his legs flap about the sides of the horse and act with neither strength nor accuracy.
When the stirrups are too short, they support more than the weight of the legs; they raise the knees and thighs and force the seat back. The trooper is then said to be hung up, and, although he has a stronger support in the stirrups, he is less secure, because he is not so far down in the saddle. Moreover, the legs necessarily become rigid; they lose all freedom of movement and in consequence all nicety (of action as aids).
The stirrups, then, should be neither too long nor too short. But of the two faults the latter is the more serious; a trooper can shorten his stirrups without anxiety, whereas he feels a certain reluctance about lengthening them. It is to be noticed that the man who loses his suppleness or his confidence always has a tendency to diminish the length of his stirrup straps.
Position of the foot in the stirrup.—At least one-third of the foot should be inserted into the stirrup; the heel should be slightly lower than the toe; the part of the sole of the foot included between the joint of the great toe and the little toe (ball of the foot) should rest upon the tread.
The support should be secured mainly on the inside portion of the foot; this method results in closing the knee and holding the lower leg in proper position.