Many of those who survived the Boston bombings will have to learn to live without an arm or a leg.
One local man who suffered a similar injury spoke about what it takes to come back.
From the waist up, Dan Lasko looks like everyone else, but below the knee, it's a different story.
"When I was told I was going to wear a prosthetic leg, I had no idea what it looked like, no idea how to walk and run again," Lasko recalled.
While in Afghanistan in 2004, the Marine was injured by an improvised explosive device. As a result, part of his leg was gone. It's a devastating injury that some in Boston are now having to deal with, too.
"You need to be strong both physically and mentally," he said.
Dr. James Daley, of Good Shepherd Rehabilitation, works with up to 1,000 amputee patients a year.
"Someone who loses a leg traumatically will have to relearn balance, will have to learn how to transfer in and out of chair or bed using just their one leg," Daley explained.
Within four weeks of surgery, Daley said patients can be fitted for their new limb, but he also said the psychological pain can be more intense than the physical.
"Loss of a limb is like losing a family member, psychologically," Daley said.
For Lasko, the drive to return to athletics drove him through the darkness. The 30-year-old runs marathons and triathlons. He also counsels and works with fellow veterans who lost a limb about what to expect moving forward.
"It's like putting on a sneaker. When it becomes that comfortable, it will be a part of you," said Lasko, who is currently studying criminal justice at Kutztown University.
"You better know your stuff man," he said to a fellow student on campus, proving post-injury, he can not only talk the talk but walk the walk as well as anyone.