Thursday, May 29, 2014

Running cadence

I have read numerous times over the years about the importance of running cadence but had never paid it too much attention. Earlier this year in January I strained my calf muscle and when I was working with my physical therapist to get over the injury, one of his recommendations was to increase my cadence. When he observed me running on the treadmill he could tell that my leg turnover was too slow and that I was taking strides that were too long. The longer strides can result in braking when your foot lands too far in front of your center of mass. This is inefficient and can lead to injuries. It turned out that I had recently purchased a new to the market Garmin 620 watch and one of its features is that it can measure running cadence as well as vertical oscillation and ground contact time (full review here). I looked back over the data collected when I was running with the 620 and it turned out that my average cadence was about 160 steps a minute, much slower than the recommended 180 steps a minute. As you can read in this article from Kinetic Revolution, it is a good idea to try to increase your cadence gradually, in increments of 5 or 10% improvements. Although the magical number of 180 steps a minute was derived by observation of elite athletes, it is not clear that this number will be optimal for all runners. I think increasing your cadence in 5-10% increments makes more sense than trying for a specific number. However, in my case, the physical therapist really wanted me to get and keep my cadence above 170 and preferably as close to 180 as possible. I found increasing the cadence quite difficult but given that I was running very limited mileage as part of the injury recovery process, it made adjusting the cadence more manageable. The most difficult part for me was learning to shorten my stride and decouple cadence and pace. My tendency when trying to increase cadence was to run faster. You don't have to run faster if you shorten your stride. You can even run slower at a faster cadence if your stride is short enough. The following three ways can be used to monitor your cadence.

1) Look at your watch and then count the number of times your right (or left) foot hits the ground for 10 seconds. Multiply by 12 to get your cadence per minute. You should try to reach 14 or 15 footfalls per 10 seconds. I found this method troublesome. I think I usually increased my cadence because I knew I was measuring it, but I wasn't sure this was representative of my cadence over the course of an entire run.

2) Download a free metronome app on your phone, set it to 90, and time your foot strike or arm swing on either your left or right side with the beat. I tried this a couple of years ago and found it very easy to ignore the beat, but I have not tried this recently.

3) Use a watch or footpod which measures cadence for you. With this method you can determine your cadence with a glance or record the cadence without ever monitoring it during a run to check how well you are really learning to run at a higher cadence.

The following pictures show representative data from the Garmin 620 of my cadence, vertical oscillation, and ground contact time before working to improve my cadence and then after having worked for a couple of months to improve the cadence. Interestingly, as the cadence improved, the vertical oscillation and ground contact time improved as well. So it's not clear to me how much value there is to measuring all three parameters versus simply measuring cadence.

Typical graphs showing cadence, vertical oscillation and ground contact time from a workout in December before I began to work on improving my cadence.

Graphs from a recent run after working for a couple of months to improve cadence. The average cadence for this run was XX. All 3 parameters improved as cadence improved.

My conclusion at this point is that increasing cadence is beneficial although it is hard to justify this with any hard data. I think I am running faster now than I was 6 months ago, but is that due to increasing cadence or the additional 6 months of training? During trail runs, the increased cadence feels like it is decreasing the impact on my legs during downhill running, and maintaining short strides with high cadence helps me to continue running rather than switch to hiking on uphill sections. The bottom line is that if your cadence is low, I encourage you to experiment with increasing the cadence and see if you notice benefits.

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