_Running._ In RUNNING the process is much the same as in walking. The chief difference is that, whereas in walking _both_ feet are never _off_ the ground at the same time, and both are _upon_ the ground at the beginning and end of each step; in running _both_ feet are never _on_ the ground at the same time, and both are _off_ the ground, and the body is flying unsupported through the air, at the beginning and end of each step (figs. 36 and 38). Thus, you may always distinguish running, though it be ever so slow, from walking, because, in the latter, the two feet are upon the ground at the same time; while, in the former, only one foot touches the ground at a time. [Illustration: Figs. 36. 37. 38. Running.] The period during which the body rests upon the ground in running is comparatively very short, being merely the time when one foot is set down in the middle of each step (fig. 37); and great force has, consequently, to be exerted to propel the body through the air during the whole remainder of the step. Hence the exertion of running is much greater than that of walking. In slow running the same parts of the foot are applied upon the ground as in walking, and in the same order; but in quick running the balls of the toes only touch the ground. The quicker we run the shorter, relatively to the rest of the step, is the time during which the foot rests upon the ground, and the greater, consequently, is the effort. After the foot leaves the ground, in running, it is thrown up behind; and, at the same time, the fore part of the sole and the toes are turned a little obliquely _in_wards, so as to prevent their catching against adjacent objects. If the toes were turned _out_, when thrown up behind, it would present a very awkward appearance, and we should frequently be tripped up by their coming in contact with substances near which we pass. While the foot is being swung forwards the toes are gradually turned a little the other way. Thus, by the time they pass the other leg the toes have lost the inclination inwards, and are directed straight _for_wards; and when the foot has reached a point in advance of the other leg, and the sole is preparing to present itself to the ground, the toes are turned a little _out_wards. This turning of the foot _in_wards and _out_wards during its movement _back_wards and _for_wards, in each step, is a graceful movement, and may be compared to the “feathering” of an oar. It takes place, also, in walking, but is less marked than in running; and in many persons it can scarcely be discerned during walking.