Ski Bindings: Different Strokes For Different Ski Styles

Considering the fact that downhill, cross-country and telemark are all different forms of the same sport, skiing, it is interesting to note how different the equipment is for the three styles. Nowhere is this more apparent than in ski bindings. These essential pieces of equipment provide the link between a skier's boots and his skis, and they immediately identify which style a skier favors. Ski bindings are designed to meet the specific challenges and needs of each type of skiing, and accordingly, they take on quite different forms.
Downhill bindings usually function by attaching the ski boot to the ski at the toe and heel. When getting into his skis, the skier thrusts the toe forward into the front bindings and then shoves his heel down into those at the back. This dual attachment allows for the high degree of control necessary in downhill skiing. However, this style of skiing also has a high likelihood of injury. To lessen this likelihood, the back bindings of downhill skis are designed to release the foot in the event of a fall. This release is triggered when a certain amount of torque is applied. Anyone who has ever "totally biffed it" on the slopes will tell you that when falling, plenty of torque is usually involved.
Downhill ski bindings can be purchased separately or as an integrated part of the skis. There are advantages to both approaches. Integrated bindings generally provide a more natural flex and better power transmission to the ski, but they also create more distance between the boot and the ski. This additional elevation can put more strain on a skier's knees when dealing with powder. Accordingly, a downhill skier will usually select separate or integrated bindings depending on the type of terrain his anticipates encountering.
Cross-country bindings are very different from their downhill relatives. A cross-country skier attaches his boots to his skis only at the toe. This system allows for the up-and-down heel movement necessary to cross-country skiing. Cross-country bindings have evolved quite a bit in recent years. The most common is the NNN (New Nordic Norm). In this system, the boot has a small bar that runs width-wise across the toe. This bar is hooked into a catch in the binding. Other systems are essentially variations on this one and as with downhill bindings, a skier will select his bindings based on the anticipated terrain. A BC (Back Country) version of the NNN binding, for example, allows the skier to deal with more rugged topography. This binding features two small ridges that run along it, corresponding with slits in the boots. The ridges create more interface between boot and ski, allowing for greater control by the skier.
Telemark bindings, like those used for cross-country, attach only the toe of the boot to the ski, leaving the heel free to move. The main difference is that Telemark bindings are more heavy-duty. Telemark skiing involves high speed descents that are (hopefully) not encountered while cross-country skiing. Hence, telemark bindings must be able to withstand the increased forces encountered such descents.