CADS: Support When You Need It
By Dick Needham, former Editor in Chief, SKI Magazine
Reprinted with permission of INSIDE TRACKS
Who'd ever thought that a rubber band, a stick and a string could make you a betteror at least a far less fatiguedskier? Vail-based engineer/inventor Walter Dandy, using just those components, put them together, called the device CADS (Constant-force Articulated Dynamic Struts), and has been saving skier's legs for some 20 years now.
When skiing, our legs act like a car's springs, absorbing and releasing energy as they extend and contract to keep our skis on the snow as terrain and conditions change. But our legs differ from a car's springs in three ways: 10 our muscles can't store energy as a spring can, 2) they're much slower to respond, and 3) they tire quickly under load.
Enter CADSan automotive-type suspension system that, according to its devotees, will make you a more efficient skier, not to mention a lot less exhausted by the end of the day.
What CADS is: a pair of fiberglass rods and cords which run between a pelvic harness and thick elastic bands that are anchored to your ski boots.
How CADS works: When you bend your knees, the elastic bands are stretched. The stretch is transmitted via the cords over pulleys to the pelvic harness, thus reducing your effective body weight and, further, diminishing the contraction strength required by your quadriceps to keep your skis in contact with the snow. And the decreased quad contraction, in turn, reduces compressive forces across the surfaces of the knee joint.
Put another way, the elastic band lifts your weight off you legs and on to the rods, and this converts the weight your legs normally bear into a downward force on the ski. It's CADS' lifting force that reduces leg muscle fatigue, knee strain and lower-back strain. It's CADS' downward force that increases edging power, snow contact, glide speed and control.
CADS are not designed for fit young skiers. They're intended for middle-aged and older skiers who advancing years have brought on fatigue, declining strength, knee, back and hip painnot to mention, a growing concern over risk of injury. Nor, in all likelihood, would younger skiers be caught dead even using them: They do look oddsomething of a cross between pogo sticks and training wheels.
No matter, CADS owners swear by them. A Leisure Trends study of CADS users revealed that 93 percent would ski much less or not at all without them (40 percent said they would be unable to ski without them), users said they could ski 34 percent more hours per day, and owners reported a 15 percent increase in days skied per season. The study concluded, "We may be looking at something that could do for skiing what the golf cart did for golf."
The Steadman-Hawkins Sports Medicine Foundation, well known for its orthopedic research, examined CADS and came to the conclusion that "CADS can effectively reduce the bone-on-bone loading of the knee joint. They also promote a more erect posture and, thus, will likely spare the quadriceps from fatigue during skiing, allowing greater ski time before tiring.
"However," the report continued, "CADS do cause a force to be applied to the ankles. Thus, they may make it more difficult to unweight for turning." (In IT's opinion, today's shaped skiswhich do not require unweightingmake this a moot point.)
We tried CADS, and although our boots weren't adapted to accept the rod ends, we managed to fabricate an attachment arrangement that enabled us to at least determine if the product worked. And it did. And we were impressed.
Like any other device designed to protect or enhance the strength of bodily parts, CADS doesn't come cheap. The price: $425. The ordering option is a two-part procedure. First, you're mailed a large box with measurement information enclosed. Then you mail back your ski boots and ski pants for the installation. Shipping (at CADS' expense) is two-day each way. Special ski poles for storage of the rods while riding lifts are included in the purchase.