Home > Uncategorized > Stride rate, running speed, and “cruise control” for runners

Stride rate, running speed, and “cruise control” for runners

February 16th, 2011

A press release from Simon Fraser University in Vancouver reported a few days ago that a pair of biomedical physiologists have invented a “cruise control” device for runners. As far as I can tell, it’s basically a metronome that provides a beat for you to synchronize your strides with; it measures your speed (presumably via GPS) and increases the cadence if you’re going slower than your desired speed, and slows it down if you’re going too fast. Right now, it’s basically a clunky backpack prototype, but future versions might be, say, an iPhone app that provides music with a “sliding tempo” to keep you on pace.

Okay, so not a device I’d feel much need for, but I can see a potential market. One hesitation, though. The entire device is predicated on the following assumption:

“We know that for higher running speeds humans prefer higher step frequencies,” says Snaterse. “This relationship can be inverted – for higher step frequencies, humans prefer higher speeds. The cruise control for runners uses this principle.”

Is that really true? There’s a lot of dogma floating around the running world that running speed is essentially independent of stride rate — if you go for a jog and gradually pick up speed until you’re nearly sprinting, your stride length will get longer and longer but your stride rate will stay essentially unchanged. For example, check out this recent post from Amby Burfoot’s blog about the potential benefits of shortening your stride:

Most of us, when we increase pace, increase stride length much more than stride rate. So our stride rate stays roughly the same at different paces, slow and fast.

Now, that doesn’t necessarily mean the reverse is true. It’s possible that when you increase speed, your stride rate stays the same, but when you increase stride rate, you speed up. And there’s some evidence that other effects might crop up when people exercise while listening to music — for example, I wrote about a study where British researchers secretly sped up and slowed down workout music by 10% and people on exercise bikes sped up and slowed down without realizing what was happening. If we’re dealing with a cruise control that, by design, is intended to make only small corrections to your pace, maybe a small effect like that is sufficient.

What does the actual research say? It’s harder to dig up than I expected, partly because it’s such an “old” question that some of the relevant studies aren’t online. Here a description of an older (1974) study from a 2009 paper:

Saito et al. [27] showed that trained runners increased their speed to 7 m/s [2:22/km, 3:50/mile] by lengthening their stride, whereas untrained runners increased stride length only up to 5.5 m/s [3:02/km, 4:53/mile]; any further increase in running speed was achieved primarily by increasing stride rate.

In other words, you have to be sprinting pretty darn fast before you start increasing stride rate instead of stride length. Still there must be some better and more recent data out that show the typical relationship between speed and stride rate — if anyone knows where I should be looking, please let me know!

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  1. Steve Magness
    February 16th, 2011 at 09:24 | #1

    It’s not true in my opinion You rely on stride length increases more so, but frequency does change. Look at what happens when 3 different elite athletes pick it up during the 10k. 3 different strategies of increasing speed:

    http://www.scienceofrunning.com/2010/11/speed-stride-length-x-stride-frequency.html

    Additionally, there was a study done by a former competitor that shows stride lengths and frequencies of some top notch NCAA Kenyan runners as they went from a slow run to about marathon pace or a notch faster.

    For the group, their average stride rate went from 175 to 196 and their relative stride length went from .68 to .93.

  2. Greg
    February 16th, 2011 at 11:58 | #2

    There is likely a difference between what Steve is talking about-highly trained athletes picking up their speed and the average runner having their stride rate artificially changed by a metronome.

  3. Richard Ayotte
    February 16th, 2011 at 16:09 | #3

    I had a fantastic run this morning and probably the best in a very long time because my calves were not sore at any time during or after the run. After reading about stride rate and the metronome tool, I dowloaded some metronome sound clips, put them on my Sansa Clip and ran at 180bpm at a speed of 7mph, which is quite a different than I normaly run at. I usually run at 180 steps per minuat at 12mph and at a much lower rate at 7mph. The result was amazing. No pain and I had a great workout. I did observe one other thing, when I ran at 180 steps per minute, the effort between 6mph and 7mph was almost non-existant but the effort at 180spm at 6mph was much greater than a lower cadence.

  4. February 18th, 2011 at 02:40 | #4

    Hi Alex,

    I just filmed a female runner (PR of around 2:33 in the marathon) at 4 different paces – 6 minutes/km, 5 min/km, 4min/km and 3:30/km. This n=1 demonstrated increasing step frequencies of 168, 172, 182 and 190 steps per minute, respectively.

    Take that for what its worth.

    As an aside, sprinters will have around 4.5 steps/second (see PV Komi’s work )- more than 270 steps/minute whereas elite 1500 metre runners have been clocked at 3.2 steps/second, on average 192 steps/minute (Leskinon 2009). Of interest, the elite group was compared to a national standard group (obviously still very good) while running at the same speed and the national standard groups frequency was 3.1 steps/second.

    Greg
    thebodymechanic.ca

    Komi’s paper: Changes in the step width, step length, and step frequency
    of the world’s top sprinters during a 100 m race

    Leskinon et al. Comparison of running kinematics between elite and national-standard 1500-m runners.Sports Biomech. 2009 Mar;8(1):1-9.
    *if you read this paper you will find that they made a mistake and reported that the “stride” frequency was 3.2 Hz. Meaning that step frequency was 6.4 – this is obviously inaccurate.

  5. February 19th, 2011 at 21:22 | #5

    From my own experience using a footpod to measure cadence in real time, my stride rate stays within a relatively narrow range (180-190) for most “easy pace” running (over a fairly wide range), but if I speed up to tempo pace or faster, my stride rate picks up considerably. I think at least for me, I use both increases and stride rate and increases in stride length depending on where exactly I am in my pacing comfort zone. Need to play with this a bit more.

  6. alex
    February 20th, 2011 at 07:00 | #6

    Thanks for all the great perspectives and data, guys — really great to have folks like you weighing in. It seems safe to conclude that both stride rate and length play a role in pace, to varying degrees in different people and at different paces. So, while it may be a reasonable “rule of thumb” to say that (within a certain range) many people accelerate primarily through increases in stride length, even then stride rate is unlikely to stay perfectly constant — which means the cruise control device could indeed work.

    I’ve actually just exchanged a few interesting e-mails with one of the cruise control researchers. Sounds like they’ve actually done a good job with the testing — I’m hoping to put up a new post with some of his comments soon.

  1. February 20th, 2011 at 21:57 | #1