And then there's Tim Don, the world-record holder in the Ironman triathlon who six months ago suffered a broken C2 vertebra when he was riding his bike and a truck turned and struck him side-on. That break is nicknamed the "hangman's fracture" because it's similar to the break caused by hanging.
Lucky to be alive, Tim had several options for recovery. The easiest would be to wear a hard collar and let the bones heal on their own, but his injury was so severe that made little sense.
Or doctors could surgically fuse his vertebra. That was the best option in terms of lessening the pain of recovery, but fusing bones would also permanently limit the range of motion in his neck. He could avoid a lot of pain... but would also end his career as an athlete.
Or he could wear a halo.
What's a halo? Here's how his doctor describes it:
"The halo is like a medieval torture device. It's a miserable experience, but it's the best option for a complete recovery with no limitations in the long run. You take titanium pins and screw them into your skull, two in front and two in back, and attach them to metal bars, which attach to a bust that you wear for three months and that you can't take off. It's pure torture." (My italics.) "But it works."
Guess what Tim chose?
Yep. The halo. The most painful option. By far.
How painful? For the first three months he had to sit motionless in a chair while his vertebra began to heal. His forehead swelled so badly the holes in his head where the pins were attached started to ooze, and when his wife would try to wipe away the discharge it hurt so badly that Tim would almost pass out. He couldn't sleep for more than an hour or so at a time. Painkillers made him so nauseous he would vomit.
And then he started training.
"If I'm going to recover, I'm going to bloody recover," Tim said. "I'm going to push the boundaries and come back as soon as I can, as best I can, and try to be even better than before. Why not?"
He and his trainer created a plan, focusing not on what he couldn't do, but what he could do. He rode an exercise bike. He did tons of core work. He uses a snorkel to swim since he can't yet twist his neck sufficiently to breathe between strokes.
And he pushes: During one session he fainted when his head swelled so much the screws put too much pressure on his skull. He had a new hole drilled in his head because medical technicians kept having to tighten the screws so often they were concerned they might push them all the way through his skull.
And on Monday, Tim will compete in the Boston Marathon -- and he expects to finish in 2 hours 50 minutes, the same 26-mile time he ran when he set the Ironman world record in 2017.
"I just know I need to give it a go because we're all trying to be faster than each other, and while I'm here, they're trying to beat my world record," Tim says. "I just don't want to be second in the world. I want to be the best-best, no matter what, and I'll do whatever it takes."
You might think Tim is crazy. And maybe he is, at least by our standards. But his story does point to a universal truth:
When you think you're exhausted, when you think you're fried, when you think you've done all you can, you always find a little more in you.
You are always capable of more than you think.
Of course you may never want to do something as extreme as Tim. You may not want to be an elite athlete. You may not want to put in endless hours chasing your dream. You may not want to suffer and sacrifice to an almost unimaginable degree.
And that's okay. I couldn't do what Tim has done. I don't even want to try to do what Tim has done.
But he does serve as the perfect reminder that almost all of our limits are self-imposed. We always have more in us.
So if you have a dream you're chasing, try harder.
You'll be glad you did -- because without effort, you won't achieve the success you really want... and that you really deserve.