Reclaiming the Mountain

The motor on a TetraSki doesn’t make it go. That’s gravity’s job. What the machine does is subtler and harder: It turns a person’s faintest movement—a breath, a twitch, a press of the foot—into a carved turn down a mountain.

It began in 2014 as a University of Utah engineering capstone project and reached the snow a year later. More than a decade on, it’s the world’s only independent alpine ski for people with complex physical injury or illness, says Jeffrey Rosenbluth, the spinal-cord-injury physician who founded the program. 

Most adaptive skiing for individuals with complex disabilities is dependent: someone holds ropes or guides the rider downhill. The TetraSki hands some of that control back. Seated in a secure support system atop two skis, the skier steers through a joystick, a sip-and-puff breath tube, or by tiny sensors that detect the faint electrical signal created by weak muscles.

“It doesn’t matter where it is—a neck muscle, a face muscle,” says Rosenbluth. “We can grab an electrical signal and translate it to make the skis move.”

That translation—muscle signal to carved turn—required engineers and clinicians to build side by side, an advantage Rosenbluth credits to the U. He can talk to mechanical engineers and computer scientists on one side of the street and therapists and nurses on the other, with the skiers themselves on the design team. And the slopes are right there: “We can take new products, test them on a mountain, and be back by lunch,” he says.

The concept grew out of TRAILS—U of U Health’s adaptive sports, wellness, and education program at the Craig H. Neilsen Rehabilitation Hospital—which since 2001 has run free adaptive recreation (skiing, cycling, watersports) for people with complex disabilities, and where every TetraSki is built and tested.

The fleet now numbers 34, spread across the country and around the world. In March, many TetraSki users gather at Powder Mountain for the TetraSki Express, an international race now in its fifth year. The next goal is bigger still: a TetraSki event at the 2034 Salt Lake City Paralympic Winter Games. “We’ve proven that these devices and athletes are super competitive,” Rosenbluth says. “Now we’re looking at a road to the Games.”