In almost any story, the hero faces challenges that are dangerous to life and/or limb. This isn’t always the case, obviously, but I think it’s obvious that there are a large number of instances where the hero gets beaten up, shot, stabbed, tortured, or injured in some other way. For people who aren’t physiotherapists, doctors, or other medical professionals the types of injuries that people can suffer can be a daunting task to look into. Because really, a person can be injured in an infinite number of ways.
Still, there are certain constraints that should* be placed on our heroes.
(*should, but often aren’t. Like when a hero gets thrown from a car in a motor accident and then walks over to the bad guys’ car and shoots them repeatedly. While adrenaline can do many wonderful things to keep a severely injured person moving, there are limits to what a body can withstand)