When it comes to cadence, the magic number is 180–or so goes the conventional thinking. At the 1984 Olympics, famed coach and running researcher Jack Daniels counted the strides of distance runners as they raced, and found nearly all of them took at least 180 steps per minute. Citing Daniels's observation, experts have long suggested that in order to minimize overstriding, lessen impact forces on the legs, and maintain forward momentum, runners should always aspire to nail that number. But cadence hinges on pace. Even Olympians take fewer steps per minute when they run at slower speeds. In fact, your easy and 5K paces may differ by up to 20 steps per minute.
Take Notes: Establish your baseline cadence for all your training speeds. Start with your easy warm-up pace. Give yourself a minute or so to adjust to the speed, then count your steps for 30 seconds. Multiply by two, record the number, then accelerate to your long training day pace. Again, give yourself a minute or so to adjust to the speed, then count your steps for 30 seconds. You should see that as your speed increases, your cadence increases. You can also do this on the track using intervals of 800 to 1200 meters.
Set a Target: To each of your recorded numbers, add five percent. This is your goal cadence for each pace. According to biomechanics researchers, five percent is an attainable target that is still big enough to significantly reduce impact. So for example, if your easy run cadence was 160, aim for 168; if your training day pace was 166, strive to hit 174.
Practice it: Perhaps the easiest way to quicken your step is to run with a metronome (there's an app for that). You will find metronomes to aid your cadence count on many watches, on apps on Google Play and in the App Store on iTunes. Seiko makes a metronome that you can purchase from Guitar Center. You can also use sites like JogTunes to find music with beats that match your desired turnover.
Otherwise, monitor your progress with a 30-second cadence check every couple miles. If you're struggling with the new target, lower it by two to three percent. Practice that revised cadence for three weeks, then bump it back up again. (from "How to Boost Your Cadence," by Alex Hutchinson, "Runner's World," October 24, 2012).
Persevere Easy Math Notes: If you wish, count the number of times either your left or your right foot touch the ground in 20 seconds. Multiply that by six to estimate number of times both your left foot and your right foot touch the ground in 60 seconds…your cadence.
Do track repeats, a speed workout: Track Repeats - Speed Workout