In mid-May, I traveled to McKinney, TX, a city located about 40 minutes outside of Dallas. The city itself is modest, with a population of just over 161,000, but flat stretches of land run for miles, making the region feel desolate. You'd never guess that many of the world's best athletes and current Olympians stop there for days or weeks at a time.The reason for their trip: The Michael Johnson Performance Center (MJP), a training and research center in partnership with Nike. The center was eponymously founded by the legendary Michael Johnson, a gold-medal-winning, world-record-setting Olympic sprinter.I headed to MJP to undergo the same advanced athlete assessment that some of Nike's top athletes complete one or more times a year.The tests are intended to identify areas an athlete can improve on to become faster and stronger than they already are, says Lance Walker, MS, PT, the global director of performance at MJP. Technology plays a pivotal role in this. You can only observe so much with your eyes, but with a 3-D motion-capture system, for example, you can see what eyeballs would miss. And while a coach can observe what your body does when you jump up and down on the ground, he won't gather the same information as a force plate measuring that same jump.To be clear, I'm not an advanced athlete — far from it. But I wanted to understand the tech that's being used to help athletes learn more about their bodies and optimize their performance, especially with the Rio Olympics just over two weeks away.My assessment revealed far more about my body than I could have realized by myself. Click through to see some of the surprising insights — and crazy gadgets — that I learned about while putting my body to the test.