I'm a nerd, so I went running today with an iPod and a GPS device, and I extracted and correlated the data from each device to show which song was playing at different points along my run and how fast I was running at each of those points, and I put that data into Excel and plotted it: 

See?  That's nerdy.  What I was trying to determine was if certain music made me run faster or not.  The specific songs don't particularly matter, but each was selected (by me) for the purpose of working out, which means they were of the rock variety, and generally loud and fast.  In general, my speed decreased throughout the run, which makes sense.  And those big spikes in the data are just GPS noise; nothing significant.  But what stands out to me is the following: 

1. I started out pretty quick, both because I had lots of energy and also because that particular song matched up exactly with my pace.  The internet says it's 162 beats per minute, which equates to a little less than three steps per second.
2. Right around the 600-second mark was when I experienced my first cramp, and then right around the 1200-second mark is when I got the second one.  Both cramps brought about a decrease in speed, and then a subsequent increase after they passed.
3. That song right about in the middle of my run, which corresponds to track number 5, seemed to have a small but noticeable effect on my speed.  That particular song has been in my music collection for a good decade, and it still pumps me up.

In conclusion, music is like a drug to me, and it makes me do things I otherwise normally wouldn't or couldn't do.  Here's to running, and music, and nerdiness!