Researchers study how to prevent wheelchair users’ repetitive stress injuries.

The wheelchair that had been Lucy Spruill’s friend for 30 years helping her achieve a master’s degree, a career, a home and a family turned against her.

Spruill learned three years ago at age 50 that she gradually had torn the tendons in both shoulders in part because she pushed improperly.

“I couldn’t raise my hands to comb my hair,” she said. “I couldn’t push myself without extreme pain.”

When it comes to repetitive stress injuries, wheelchair-users have typists beat by a mile. They grip and push wheel rims day in and day out, pinching nerves and damaging tendons.

Research at the University of Pittsburgh could help doctors and therapists learn how to train wheelchair-users better.

The attitude has been, “Hey, pain is part of the ticket of using a wheelchair. Get used to it,” said Rory Cooper, director of the Human Engineering and Research Lab. But “the point isn’t being alive, it’s having a life.”

In the largest study of its kind, the lab is studying the way people and their wheelchairs work together. Computers are integrated into the chair’s wheels, and infrared sensors line the person’s arm to pinpoint offending positions.

About 1.5 million Americans use wheelchairs. Of them, studies have shown that at least half suffer from carpal tunnel syndrome the compression of the medial nerve at the wrist and half develop shoulder injuries such as rotator cuff tendinitis or tears, said Dr. Michael Boninger, the lab’s medical director.

For wheelchair-users, any injury that limits hand or shoulder movement is particularly devastating “for someone who walks with their arms,” Boninger said.

Shoulder pain can prevent a wheelchair-user from moving from a bed to the chair or from the chair to a toilet or car.

“Most of the patients are people who are fighters, and they’ve overcome a disability, and it’s like being hit with another one,” he said. “They go from being totally independent to being totally dependent.”