This should be filed under: how music and swimming made me a better runner.
Several years ago I learned that, despite running different distances, most elite runners run around 180 steps per minute, or 90 steps per foot per minute. I worked on increasing my cadence to about 90, and have felt lighter and quicker because of it. (On a somewhat related note, I also read a great suggestion in a running magazine to imagine, while running, that a rope was attached to my sternum, pulling me forward. Visualizing this causes me to open up my chest and increase my forward momentum.)
A few years ago I started swimming for triathlons, and knew I needed to learn to breathe on both sides. I am a natural right-sided breather but felt I would have a smoother, more even stroke if I learned to breathe every 3 strokes. (I hope I can get that down to every 5 at some point!) So, with some good tips and encouragement from my swim coach, I trained myself to do bilateral breathing and am more or less comfortable with it.
Training for California International Marathon in December 2005, I noticed that my running was not completely even--I tended to favor my dominant side just as I did in swimming. I thought that if a 3-count rhythm worked for swimming, maybe the same would hold true for running. I also wanted to make sure I was keeping to a cadence of 90 steps per foot per minute. So counting "1-2-3, 2-2-3, 3-2-3, 4-2-3," where each beat is a step (i.e., "1-2-3" = right-left-right foot steps), I would count to 180/3 or 60 sets of 3. With this method, though, I found I was still favoring the right foot by emphasizing every other set of 3 steps.
In order to force myself to alternate the emphasis between right and left, I adopted the 9/8 time signature, where each measure consists of 3 sets of 8th notes, grouped in triplets, with the beat on the first 8th note for each measure. Each 8th note is one foot strike. I've never been a fan of this time signature in vocal works (or 12/8--even worse in general, but this one found here is okay), because the music tends to be a little sappy for my tastes. It has served me well in running, though!
Here's how it works:
Count in your head or mutter under your breath, "1-2-3, 2-2-3, 3-2-3" as one set. Get in this rhythm so you don't really have to count all the individual footsteps. I would think something like, "1-ta-ta, 2-ta-ta, 3-ta-ta," as one set, which consists of 9 footsteps, or 3 sets of triplets. Then the next set would be "2-ta-ta, 2-ta-ta, 3-ta-ta" and then "3-ta-ta, 2-ta-ta, 3-ta-ta," and "4-ta-ta, 2-ta-ta, 3-ta-ta" and so on. Eventually, just think, "1..., 2..., 3...," with each count representing 3 steps. The first beat I use to count how many sets I've run. If you are running at a cadence of 90 (or 180 steps per minute) then you would have 20 sets in one minute. Using this method will cause each subsequent set to start on, and the emphasis to therefore fall on, alternating feet. I have found that, using this method, my running form is much more even, comfortable, light and fast.
Sometimes, when I am trying to focus on positive mental thoughts, rather than "Ugh! I'm tired!" I will use this method and think something like, "one..., strong..., smooth..., two..., strong..., smooth..., three..., strong..., smooth..." where each word falls on every 3rd step, and I am still counting in 3 groups of 3 steps. Once the rhythm is ingrained, I might replace counting with another positive word, such as "fast" or whatever pep I might need at the moment.
Another helpful tip is to note that 180 steps per minute is equivalent to 3 steps per second. So I might do a quick cadence check during a run and count "1, ta, ta, 2, ta, ta, 3, ta, ta,..." and so on and make sure that 20 seconds have elapsed once I've counted to 20. If I'm slowing down my cadence, I can pick it up again.
This method worked really well for me at CIM 2005--I posted my still-current personal best of 3:39, fulfilling my 10-year goal of qualifying for the Boston Marathon, which I ran in 2006. (It took more than counting, though!)
If this is all too confusing, here is the bottom line.
Try counting, where each count is one foot strike, "1-2-3, 2-2-3, 3-2-3, 1-2-3, 2-2-3, 3-2-3,..." and so on. Emphasize the first count of each set (in bold). Run 3 steps per second. This helped me to run more evenly, quickly and relaxed.