Note 150-* — Chapter VIII · THE SEAT.

The muscles of our limbs are attached at each end to bones, between which there are one or more joints; and they act by their power of contraction, which enables them to become shortened to about two-thirds of their length. The full effect of this contraction can be obtained by a muscle only when its points of attachment are separated to their utmost extent, and it becomes diminished in proportion as the distance between them is shortened by the bending of the intermediate joint or joints, up to a length equal to that of the muscle in a fully contracted state, at which limit the muscle is out of “play.” The muscles which bend the knee are attached, at one end, to the back of the shin bone, close to the knee; and at the other extremity, to the end of the ischium (lower part of the pelvis), which is below the hip joints. Consequently, the more the knee is bent and the more the upper part of the body is drawn back by the play of the hip joints, the nearer are the opposite points of attachment of these respective muscles brought together, and the less power will they have to hook back the knee. Hence the more a lady leans back, when going over a fence for instance, the less firmly will she be able to hook her leg round the upper crutch. Therefore, ladies who adopt this hooked-back seat, are invariably prompted by the requirements of this position, to bend forward, and have more or less difficulty in bringing the upper part of the body back.