Monday, April 27, 2009

Stride Right: How Cadence Affects Running Performance

Recently I was at Jack Rabbit Sports in Brooklyn buying new running shoes. They analyze your running gait by using a treadmill and video equipment. I was told that I was bouncing too much. All the movement up and down was taking away from my forward momentum, slowing me down and also forcing more impact on my joints upon landing. The Jack Rabbit staffer recommended I read ChiRunning to help me adjust my form.

I went to work breaking down my running form and trying to figure out how to be more efficient. I bought Danny Dreyer's ChiRunning as well as other books on running technique. One key problem I found was that my stride was too long for the speed and the distances I was running. This was not as huge of an issue when I was running 2 to 3 miles on the treadmill but when I started training for a marathon and running for 10 miles or more I could feel my ITB (or iliotibial band) tighten with some accompanying knee pain. Icing and stretching helped but I wanted to reduce as much of the impact as possible in the first place.

According to Danny:

One of the most common and significant problems I see in runners is too long a stride length when running slowly. This is very inefficient and exhausting to the body. If your cadence is slower than 85 strides per minute, your feet stay in contact with the ground longer, which means that your legs are supporting your body weight for a longer period of time. Conversely, if your stride is over 85 strides per minute, you'll spend significantly less time on your feet, saving valuable energy. (ChiRunning, p81)

Dreyer recommends a cadence of between 85 and 90 strides per minute. That means if you are counting how many times you step with your left foot for one minute of running it should be 85-90 times. For both feet that would be a cadence of 170 to 180 steps per minute. The more I researched the more this magic number kept appearing. Up until this point I always thought the faster you ran the more steps you would take per minute. It turns out this is incorrect, it is actually the length of your stride that changes while the number of steps remains relatively consistent.

Exercise physiologist Jack Daniels, Ph.D., described by Runner's World as the "World's Best Running Coach" is known for his comprehensive research in sport performance and coaching of elite runners.

He writes in Daniel's Running Formula:

One of the first things I teach new runners is some basics about running cadence, or stride rate. Almost all elite distance runners (both men and women) tend to stride at about the same rate: 180 or more steps per minute. This means that they're taking 90 or more steps with each foot per minute, a rate that doesn't vary much even when they're not running fast. The main change that occurs as runners go faster is in stride length; the faster they go, the longer the stride rate becomes, with little change in rate of leg turnover. ... I try to save runners a lot of grief by encouraging them to convert to a stride rate associated with less landing shock and more efficient use of energy. ... We often talk about getting into a good running rhythm, and the one you want to get into involves 180 steps or more steps per minute. (p93-4)

There are a number of things I try to be conscious of while running to reduce my bounce: core strength, flexibility, alignment, arm swing etc. However, increasing my cadence and shortening my stride was the easiest fix that made the most difference right away.

So, how do you know if you are training at the correct cadence? Danny Dreyer encourages taking a metronome on runs. As a former young music student this sends me into memories of painful piano lessons and makes me want to tear my hair out. You may be guessing where I am going with this by now. My newfound knowledge and experience led me to choose a specific tempo for the new music. The beats per minute (b.p.m.) in music is what people tend to sync their steps per minute to if they are running to the rhythm of a song. Initially I had planned to write at different tempos and let people choose songs that matched their unique cadences or the speed they wanted to go. I was amazed to discover that I could run at the same cadence whether I was going fast or slow. Music became a useful tool to remaining consistent over an extended period of time.

The problem with most popular music in terms of running is that it is not written at an ideal tempo. It usually clocks in between 110 and 140 b.p.m. Of course there are exceptions which is why it is possible to find songs that work. The other problem with making a running playlist is that chances are the songs are all at different tempos. This again leads to problems of consistency and may inhibit your training.

Music can be very useful in training specifically in the case of developing a consistent stride rate when it is set to the correct tempo. I can hear voices of running coaches in my head arguing with the idea of running to music so I will again emphasize: it is important to be able to run without music so that you are prepared for race conditions and can listen in the moment to your body and what is going on around you. However, if you have multiple training runs per week there is no harm in having a couple of them to focus on rhythm and letting music add some extra vibrance.

In Songs for Running (the title of my new 6 song E.P.) I wrote the first 3 songs with the same beats and structure but at increasing tempos of 160, 170 and 180 b.p.m. to help people get used to the cadence if they are not already. After that all songs are written at the 180 b.p.m. gold standard.


Lela said...

Erin, this is awesome! Congratulations.

Jess said...

I look forward to running with your songs, Lady. Nice legs here, btw.

Lady Southpaw said...

Haha, which legs mine or yours?

Jess said...

All four. Hot.