We’ve decided to let you in on a little secret. A secret known only to skimo racers, parapalegics, high-school physics teachers and the rare students who retain knowledge after the test. The secret is a simple machine known as the Inclined Plane, shown below.
Like all machines, the Inclined Plane provides a mechanical advantage. In this case, the advantage is defined by the ratio of an object’s weight (Fm) divided by the force needed to pull it up a mountain (Fi). If you vertically lifted your skis, boots, and bindings every step, you will need to apply a force equal to the combined weight of your gear. However, if you slide it up an inclined plane, the force required will be less. The resulting mechanical advantage (MA) is defined as follows:
As is evident in the above formula, the advantage provided by the Inclined Plane is inversely related to the slope angle, theta. That angle is calculated as the arctangent of a mountain’s Vert (height) and its Skirt (if you somehow skirted to its center):
It should now be clear why guys and gals in skin suits prefer lower angle tracks. The lower the Vert-to-Skirt ratio, the greater the mechanical advantage. Those wise old tight-wearers are using an Inclined Plane to cheat the game of life. This is the simple but eye-opening secret.
Disclaimer time: the above formulas represent a frictionless inclined plane. The force to pull a ski along the plane (Fi) increases as friction increases. With certain nylon skins at certain slope angles, the mechanical advantage of the inclined plane might be entirely negated. This possibly explains why some folks naturally stomp up the mountain instead of slide.
If you have skins with decent glide, or even optimize for that quality, you can really use the slope of the mountain to your advantage. It can take time to train your muscles to perform a sliding motion instead of a stepping motion, but the results are longer, more enjoyable days.
Please share this secret with your slow friends: