Mono Ski Terminology (P-Z)

Pelvis Tilt. People with SCI tend to sit with their pelvises tilted back in low-back, lightweight wheelchairs. While fairly stable, this posture is not dynamic and causes lower-back pain. In a mono-ski, the pelvis must be rotated forward and supported in a more dynamic position.

Pivot Points.A mechanism without shock absorbers moves because it has at least one pair of pivot points. A mono-ski with a four-bar linkage mechanism has eight pairs of pivots. The system lasts longer with bronze or nylite brushings and even longer with bearings.

Quick-release Ski. Many new mono-skis use a standard boot plate and competition bindings to hold the plate to the ski. In this case, small tabs are often placed at the toe of the boot plate to prevent the toe from releasing on the binding.

Seating Orthosis. Most top U.S. mono-skiers use customized seating orthoses. If you decide to have an orthosis made, it is important to be familiar with many different mono-skis so you can determine your most functional body position for skiing. Know where you want your feet, knees, pelvis, and upper body positioned over the ski. Ideally, make a mock-up of the support structure or, better yet, sit in your mono-ski during the plaster splinting process with your orthotist. An orthotist's services are worth trying to get your insurance company to pay for, since it is the most important and probably most expensive piece of adaptive equipment needed to interface you to the sport of skiing. A well-cast mold can also be used to make seats for racing wheelchairs, kayaking, cross-country skiing, etc.

Self-loading Lift Mechanism. This raises the mono-ski from skiing height to chairlift loading height. Find out if additional hardware is required and how long it takes to actuate the mechanism. Determine if assistance is required and how much weight this part of the mechanism adds to the mono-ski.

Shock Absorber. The shock absorber, which comes in a variety of lengths and ranges of travel, consists of the hydraulic dampener and a spring. "Travel" is the distance the shock moves from full extension to full compression. Spring rate and dampening ratios are determined by the height of the bumps and the speed at which you plan to go over them.

Spring. The spring on many shock absorbers is removable. Variable spring rates are available; a softer spring works better on a downhill course, and stiffer ones are better on a slalom course.

Suspension Linkage. The suspension-linkage configuration determines the path of movement the skier's center of mass will take from full compression to full rebound. A scissor-type mechanism and a single-pivot linkage allow only vertical movement. Four-bar linkages may have short or long bars; depending on their angle, the longer will likely result in less forward displacement. For safety reasons, do not use any suspension that only moves part of the body. The shock absorber's position and orientation have nothing to do with the relative path of the mechanism's movement.

T-bar Hardware. If you ever ski in Europe, you'll encounter many T-bar lifts. In choosing hardware to use with a T-bar, consider the best attachment point to the mono-ski. Pull in front of and slightly above the skier's center of mass.

I use hardware that attaches to my knee support: A loop of line goes from my left knee to my right, with a quick release at both knees. At the front of the loop, a plastic-coated rope covers the line and is looped over the T-bar. I keep a release line in my hand while riding up. At the top, I pull the line to open the rope. If that gets frozen, I can release the attachment points to my mono-ski at the knees. This is a triple-redundant system; I recommend at least a double-redundant system. Don't rely on your ability to release a plastic buckle. I saw one team member get wrapped around a post going up the T-bar, and the failure of a plastic buckle is what saved his life! Be sure to have a good release system.

Vertical Displacement. This is the total vertical movement from full compression to full rebound, measured from some point on the mono-ski perpendicular to the surface of the snow.

Weight of Equipment. The lighter the better. Remember, someone has to carry these things. A pair of inline-skate wheels can be attached at the binding to enable your ski to be pulled along the ground.

Terminology (A-O)