180 bpm - More Testing

This past Tuesday I brought up the topic of running at a cadence of 180 bpm HERE.  Your responses were quite varied (as I expected) and I'm interested enough in the topic that I wanted to dive a little deeper into it.

I'd like to dedicate the rest of this blog to Shelby and Amanda!  

You ladies have not even seen true "science nerd" come out of me yet!

I'd like to first take a moment and highlight Ron's comment on the previous post.  Ron treats running injuries first hand and point out that studies have certainly shown increases in cadence to be beneficial in decreasing your ground force reaction.  A 5% increase in cadence - going from 160 bpm to 168 - will decrease the ground reaction force by 20% which can help avoid injuries.  And I can't agree more with how Ron put it:

"The best runners just run at 180 bpm, should you? Not necessarily but are your feet moving fast enough for you? That is a better question...."

Is 180 bpm the best rhythm for you?  It may be, but I would suggest that it is not for everyone. 

Now it gets fun...

I began thinking...  If 180 bpm isn't for everyone - if some people are better at 170 bpm and others at 190 bpm - how you would go about determining what your best cadence is.  And would that cadence be the best for you in a 5k race AND a marathon?  As any runner will tell you, the difference in pace between a 5K and a marathon is quite noticeable.  Even Ryan Hall who ran a mile in just over 4:00 still runs his marathons at a 4:45 pace, forty five seconds slower.  The rest of us age-groupers and recreational runners might have a full minute or two (or more) difference between those paces. 

When I tested my cadence the other day to music at 180bpm, my major conclusion was that my legs moved evenly with that cadence around a 7:00 pace.  However, when I increased the speed, my cadence also increased and vice-versa.  Now, while some people consider me a freak, an animal, or something quite unique in any way, I consider myself quite the normal runner.  And given that fact, I'd be willing to bet that most of us follow that same cadence pattern over a range of running speeds. 

So what if I was to say (again going back to my previous post), that for some runners working towards a "perfect cadence" is like working backwards?  What if instead of changing your cadence, you should change your speed? 

Hear me out!

If everyone runs at a given cadence while at a given speed and cadence correlates directly to their speed as speed changes, then there must be a speed at which they hit their own most efficient cadence.  Right?

So as any true scientist does, I made myself my own lab rat.

Yesterday I got to work a little early and jumped on a treadmill.  The plan was to run at a range of speeds - 6.0 to 12.0 mph (10:00 to 5:00 pace) - and determine my cadence over that range.  In order to mimic road conditions, I ran the entire experiment at 1.0% incline.  Once I felt steady in my pace at a given speed, I started my stop watch for 30 seconds while I counted my strides. 

My hypothesis, given the previous test, was that I'd hit a rough 180 bpm somewhere around 7:00 pace and that my cadence would have a direct correlation to my speed.

It turns out I was spot on!

My cadence ranged from as low as 162 bpm at a speed of 6.0 mph (10:00 pace) all the way up to 208 bpm at 12.0 mph (5:00 pace).  You'll also notice that one of the data points is colored RED.  That is the point at which I hit 180 bpm smack dab on the nose.  You'll also notice that this data point is at a speed of 8.5 mph or 7:00 pace just as I predicted.  So I know that this fits with my previous test which is always good. 

What can I take away from this?
I know now that my cadence changes as I change speed, which I think most people would have agreed with even prior to the experiment based on their own experience.  I can also say that within this range of speed/pace, the correlation of cadence to speed seems pretty close to linear.  I would postulate, however, that as I extend the range, I would find that this is only a small part of what really is a sigmoidal relationship.

Does this experiment tell me what my perfect cadence is?
NO!  I would need much more high-tech experimentation to determine the range of ground force reaction, long term studies to determine my susceptibility to injury, and such.  All I can say is that within the range of paces that I normally run, I hover around the 180bpm mark. 

Does this tell me how to determine your most efficient cadence?
NO!  But in theory, I may be one step closer.  From my own experience, I've always said that I naturally run an average 7:00 pace.  If I speed up, I can feel myself pushing and if I slow down I can feel myself holding back.  That's is not always the exact case, but I would say it is true on average.  And what cadence did I find I run at when I run at a 7:00 pace?, 180 bpm.  Given that I would credit the number 180 bpm as being within the range of most runners and their most efficient pace/cadence, I would bet that for some runners, the cadence at your "natural pace" is your most muscle efficient cadence.  However, I won't say that that is the best cadence for you.  That would require further testing.

And this brings me back to fleshing out my previous thought.

Conclusions
Provided that everyone has an unique 'most efficient cadence' based on running efficiency and that we all have a direct relationship between speed and cadence, I might bet that wherever this cadence lies, it is at what I will call our "natural pace."  For me, that is around 7:00 pace.  I would also bet that as you increase your natural pace through training, your cadence profile will shift.  Therefore, as I try to shift from 7:00 to 6:30 and below, I should focus more on the speed and as my body adjusts, the cadence will follow.  I will be keeping track of my cadence profile from now on to test that very theory!

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Questions

1.  Have you ever made yourself your own lab rat?
We've all done it in some way.  

2.  Do you have an idea of what your "natural pace" is?  If so, have you ever felt it change?
My natural pace has begun to feel slower this year as I've focused more on distance and less on speed.  I'll be working to speed it up over the winter and into next season.

3.  Any other thoughts on the whole cadence topic?
I'm always interested to hear your thoughts!


Swim fast.  Bike smart.  Run hard.