THE USE OF MUSCLES IN THE BODY 127 



sole placed on the ground, the heel touching it first, and the base 

 of support being thus widened from before back, a fall is pre- 

 vented. Meanwhile the right leg is kept straight, but inclines 

 forwards above with the trunk. when the latter advances, and as 

 this occurs the sole gradually leaves the ground, commencing 

 with the heel. When the step of the left leg is completed the 

 great toe of the right alone is in contact with the support. With 

 this a push is given which sends the trunk on over the left leg, 

 which is now kept rigid, except at the ankle-joint; and the right 

 knee being bent that limb swings forwards, its foot just clearing 

 the ground as the left did before. The Body is meanwhile sup- 

 ported on the left foot alone, but when the right completes its 

 step the knee of that leg is straightened and the foot thus placed, 

 heel first, on the ground. Meanwhile the left foot has been gradu- 

 ally leaving the ground, and its toes only are at that moment 

 upon it : from these a push is given, as before, with the right foot, 

 and the knee being bent so as to raise the foot, the left leg swings 

 forwards at the hip-joint to make a fresh step. 



During each step the whole Body sways up and down and also 

 from side to side. It is highest at the moment when the advanc- 

 ing trunk is vertically over the foot supporting it, and then sinks 

 until the moment when the advancing foot touches the ground, 

 when it is lowest. From this moment it rises as it swings forward 

 on this foot, until it is vertically over it, and then sinks again 

 until the other touches the ground; and so on. At the same time, 

 as its weight is alternately transferred from the right to the left 

 foot and vice versa, there is a slight lateral sway, commonly more 

 marked in women than in men, and which when excessive pro- 

 duces an ugly " waddling" gait. 



The length of each step is primarily dependent on the length 

 of the legs; but can be controlled within wide limits by special 

 muscular effort. In easy walking little muscular work is em- 

 ployed to carry the rear leg forwards after it has given its push. 

 When its foot is raised from the ground it swings on, like a pen- 

 dulum; but in fast walking the muscles, passing in front of the hip- 

 joint, from the pelvis to the limb, by their contraction forcibly 

 carry the leg forwards. The easiest step, that in which there is 

 most economy of labor, is that in which the limb is let swing 

 freely, and since a short pendulum swings faster than a longer, 



