If you’re planning to enter a race, allow a little extra time to reach the finish line. You’re not as fast as you used to be. It’s not just you. Americans on the whole are not running as fast as we used to, and we’re getting even slower every year. The only thing we’re quick at is coming up with excuses to rationalize the slower times we’re posting. This news comes from Jens Jakob Andersen, a statistician at the Copenhagen Business School.