This is not quite a fair simile, for, while the cases of the bicycle and of the ski-runner in the single-track position are exactly analogous, a man with his skis apart is not a rigid construction like a tricycle, but, by letting his knees give and by swaying his body, can adapt himself to the change of gradient.
Still, the tendency is always, especially in the case of the beginner, for the legs to stiffen when they ought to yield, and on this account alone the single-track position is the safer.
Fig. 27.
There are, moreover, two further objections—and very strong ones—to separating the skis.
One is that it is impossible to run with the skis apart without holding the feet about level, instead of keeping one well ahead of the other. With the feet level the runner has far less stability in a fore and aft direction, and, without support from his stick, can hardly hope to keep his balance in the event of a very sudden change of speed. The other objection is that when the skis are separated each one has to be kept straight independently. At a low speed it is perhaps not very difficult to do this, but at a high speed it is by no means easy, and, of course, any divergence or convergence of the skis is almost certain to cause a fall before it can be checked.
When held against each other, however, the skis, if properly made, will run perfectly straight and need no attention at all. Obviously they cannot converge, and the least inward pressure or edging will prevent them from running apart.
The single-track position, then, has many advantages. The only thing against it is its unsteadiness in the event of side-slip. But under ordinary conditions of snow, a ski, when moving straight ahead, either directly down the slope or obliquely across it, will show no tendency to side-slip, not even when, in the latter case, the slope is very steep (provided, of course, the ski be held normally, i.e. edged). Under such conditions you can always run with the skis held close together in either the normal or the Telemark position, and there can be no excuse for deliberately separating them.
When running on a hard icy crust, however, it is sometimes impossible to prevent the skis from side-slipping. They are, of course, much more apt to side-slip when moving across a slope (especially a steep one) than when running straight down it; indeed when traversing a steep slope they may side-slip even in soft snow if that is shallow and rests on a slippery crust. But though they will generally run straight downhill with absolute steadiness on snow that makes them side-slip badly when traversing, the surface may be so extremely slippery that they will side-slip even in a direct descent owing to small lateral undulations of the ground.