Talk about toughness! The U.S. Men's 4x400 relay team was plagued by injury, but none of them top it off like Manteo Mitchell. About halfway through his leg of the preliminary race, he heard a pop and immediately knew something was wrong. With his teammates in mind, he finished his portion and then limped to the sidelines.

After the race Manteo Mitchell learned that he had a complete break of his left fibula (calf bone). Basically, he ran 200 meters with a broken leg and still finished with a very respectable time of 46.1 seconds. In fact, the U.S. team tied with the Bahamas for the fastest time ever in the first round of an Olympic relay race.

Mitchell will spend the next 4-6 weeks on crutches and in a walking brace. Walking braces, also known as medical walking boots, help support the injury while it heals. The walking brace stabilizes the bones and protects the leg from impact with its hard exterior shell. Earlier in the week Mitchell had slipped on stairs and fallen, but thought nothing of it. It's amazing how a such a small incident led to a large injury. The human body accomplishes incredible feats, and it's a good thing that we have devices like walking boots to support us!