In a high-tech sculpture studio in Albertson, where plaster casts of human limbs cluttered nearby tables, Joe Johnson lifted what remains of his left shin and flexed his calf muscle.
"Just that little bit helps me enormously," he said, admiring the subtle motion of the stump before fitting his leg into a prosthetic foot and dancing an animated jig.
As he did, Dan Bastian, who made the prosthetic foot after Johnson lost his lower leg in a 2010 motorcycle crash, looked on approvingly.
"Don't mess with him," Bastian warned playfully, as Johnson threw high karate kicks into the air. "He's a black belt."
Bastian's interest in prosthetic devices dates back 24 years, when he chose to have his right leg amputated after a nearly 10-year battle with bone cancer. He and a business partner opened a prosthetics manufacturing studio in Albertson -- Progressive Orthotics & Prosthetics -- in 1999.
Since then, Bastian, of Massapequa, has helped hundreds of area amputees get on with their lives, including a Vietnam veteran who lost a leg in the war, a Mineola gym teacher whose hand was crushed in the aftermath of superstorm Sandy, and a toddler who uses a mechanical hand because of a congenital malformity.
Bastian said that although the final result of helping people recover the use of an amputated limb is enormously fulfilling, decisions he must make along the way can be stressful.
That's because doctors or patients contemplating an amputation sometimes seek Bastian's advice on whether and how much of a limb should be cut away. Where the cut is made can influence the effectiveness of a prosthetic.
"It can be stressful," said Bastian, who fought to save his own withered leg for nearly 10 years before deciding to have it amputated. "Even though I know it was the right decision for me, you don't know how someone else will handle it."
Johnson, 52, turned to Bastian for advice after a mishap on a Florida back road in June 2010 crushed his leg.
Johnson, a former Marine, had been participating in a 7,000-mile motorcycle race to raise money for Building Homes for Heroes, a charity that provides housing for injured veterans. He and another motorcyclist collided just hours after starting what was to have been a two-week haul from Key West to Anchorage, Alaska.
For Johnson, who worked on movie sets as a precision driver for camera vehicles, the accident threatened to curtail his relatively physical life.
But while Johnson was still in a hospital bed, a mutual friend persuaded him to talk to Bastian, a skier and golfer who makes a point of walking around with the metal shaft and plastic knee of his prosthetic leg exposed for all to see.
"When I saw him standing there in shorts, and him telling me that I was going to be fine, it kind of hit home that I was going to be OK," Johnson said.
Johnson has since returned to work arranging theatrical sets in Manhattan, though he has yet to resume precision driving.
In the less than three years since his accident, he has also taken up karate to improve his balance. And he has participated in "sprint triathlons" to build strength and endurance. One of the interchangeable prosthetics he wears is a blade-like foot fitted with a rubber sole for running. Another is fitted with a work boot, with which he ambles around theater sets while on the job.
For Johnson, the loss of limbs caused by the Boston Marathon bombings are a sobering reminder of his accident.
He said his experience should assure marathon amputees that the loss of limbs need not significantly limit their lives.
"Some of the injuries were quite horrific," he said, his voice subdued.
"Initially, it's going to be about hooking up with the right people for physical therapy and just remaining tremendously positive," he continued. "Life doesn't come to a standstill -- or shouldn't."