150 THE SEAT. 



effectively, only when the ball of the foot rests on the 

 stirrup. If the foot is put " home," the ankle joint will 

 have little or no play. When using the leaping head, 

 we should bear in mind that the action of the muscles 

 which straighten the ankle joint, should be independent 

 of the body. If this condition is not observed, the 

 tendency will be to put undue weight on the stirrup, 

 and to bring the body forward. 



It is evident that placing weight on the stirrup, 

 without at the same time exerting counterbalancing 

 pressure against the leaping head, will not only put 

 undue weight on the near side, but will also bring the 

 body forward. 



The right leg can help in obtaining grip, either by 

 bending the knee and bringing the calf of the leg- 

 round the upper crutch, or by lateral pressure of the 

 knee against that crutch. The former method is 

 entirely wrong, because it cannot be fully carried out, 

 except by bringing the body forward,* which action is 



* 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 inter- 

 mediate 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 respec- 

 tive 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 in- 

 stance, the less firmly will she be able to hook her leg round the upper crutch. 



