Even sudden changes of speed have little power to disturb your balance when you are running in this attitude. If the gradient suddenly becomes much steeper, as in Plates [XVIII.] and [XIX.], you should give a determined plunge forwards, as though trying to get ahead of your skis. If, however, you are taken by surprise, and run suddenly on to an invisible icy patch or over a steep drop in bad light, you will probably at the worst only find your weight thrown on to the back foot, and will be able to recover yourself. On the other hand, if the speed is checked and you are thrown forwards, the back foot will tend to rise into the air, and, receiving the weight of the ski, will most likely just save you. If the check is so abrupt as to throw you right off your balance forwards, you can often save yourself by bringing, with a quick stride, the disengaged back foot to the front to receive your weight. Indeed you are almost sure to do so instinctively.
Another position, which is employed by some runners under circumstances such as I have just described, is as follows:—
The runner crouches as low as possible, almost sitting on the raised heel of the back foot; the front leg, from the knee downwards, is perpendicular to the ski, but its foot is not much farther ahead than in the normal running position; the back knee is pressed against the inside of the front leg, just above the ankle.
This attitude is less tiring to hold than the Telemark position, but is, I think, less of a safeguard to the balance when the speed changes suddenly or the ground is very rough.
All that I have just said has reference only to the preservation of the balance in a fore and aft direction. The question of lateral stability is far simpler; on all ordinary occasions it is sufficiently secured by keeping the skis as close together, and so making as narrow a track as possible.
The reason for this is not quite self-evident, but is easily explained.
If a bicycle be ridden on bumpy ground, it will not be tilted sideways as it crosses the side of an undulation, and will have no tendency to upset unless it actually side-slips.
A tricycle, on the other hand, or any vehicle with a wide wheel-base, will under similar circumstances be more or less tilted according to the angle of the ground, and will, unless it has a very wide wheel-base and a low centre of gravity, be easily upset by a sudden transverse variation in the angle of the ground, especially when moving fast.
The diagram shows how a ski-runner when holding his skis apart may be compared with a tricycle, when holding them together with a bicycle.