Aug 6, 2012 3:05 PM
TUCSON - This weekend saw the end of an era with Michael Phelps swimming in the final Olympic competition of his career - the 4x100-meter medley relay. With the help of Tucson swimmer Matt Grevers, Phelps was able to close out his career with his 22nd Gold medal!
Usain Bolt once again proved why he's considered the fastest man in the world by winning a second consecutive Gold megal in the 100m dash. Click here to watch the video of his run.
How does he do it? Watch this NBC Sports video to discover the Science of the Olympics: Usain Bolt's Biomechanics.
And, if you're a cable, satellite or telco subscriber with MSNBC or CNBC, you can watch any event, any time, live-streaming an on demand! Click here for details.
Time is running out to enter to win our various Olympic contests!