"We have a lot of lower extremity injuries, so I think the damage was low to the ground and wasn't up, " Dr Burke said.

BBC: Boston Marathon 'bombing suspect' seen on video

"We have a lot of lower-extremity injuries, so I think the damage was low to the ground and wasn't up, " Dr. Peter Burke said.

NPR: Boston Official: Video Footage Shows Bomb Suspect

"Sports involving running, cutting, jumping and quick changes in direction are associated with lower-extremity injuries, just as sports involving overhead activities usually are associated with upper extremity injuries, " explains Giangarra.

CNN: Ways to help your children stay in the game injury-free