Cadence Candor: "Look ma, no gears!"

Willie, agreed. My form has been feeling really good lately, and I too notice the power you get from the Achilles. I think my form has always been OK, but with greater experience and intellectualization of the process, it seems to becoming more finely honed these days. I never had a problem with over-striding--at least not barefoot (I don't remember how I ran shod)--so the 180 rule was always kind of a mystery to me, and it just seems odd (counterintuitive) to pull a nice even number like that out of thin air and expect to apply it universally, across the board, to every runner. Organic systems, unlike physical processes, rarely obey neat geometries and algorithms (with the exception of sea shells and the like). However, after my brief reading up on the topic, and after reading the replies/comments here and elsewhere, I would hypothesize that those runners who do find themselves unconsciously gravitating to a high, steady cadence, no matter the pace, are probably what I have termed 'rate-dominant' runners. I would further hypothesize that someone like me, whose turnover only gets up to 180 spm when up around 7mm pace, is probably a stride-dominant runner. This doesn't mean that I'm necessarily over-striding, but rather I am able to deliver sufficient force with each stride to propel me along at 10mm pace with a relatively low cadence of 162-4. It is with this in mind that I found conclusions 6 & 7 (culled from my reading) to also be a bit of a revelation.

I would love to get my hands on some video of this 162spm :)
 
BG, I'm with you. I've done precious little to adjust my running form/style, although I have noticed that my form feels better with slightly faster paces. My interest in cadence arises mostly out of intellectual curiosity (it seems counter-intuitive to keep one's cadence steady no matter the speed, which is why I finally got around to checking my own), but also the fact that my brother and nephew are asking for some coaching.
So, I just had a thought about this as I was re-reading it. Maybe someone who knows more about mechanics can chime in here as well. Is it possible that those whose cadence stays steady no matter the pace, maybe they operate kind of like a CVT (continuously variable transmission). Basically to my knowledge (I'm so not a mechanic so this is really dumbed down) these types of transmissions actually don't have gears per say, but operate on a band or something so they continuously "float" in the optimal range. It's like a snow cats (snow machine, snow mobile, what have you) transmission. This is kind of how I feel when running, that I don't really shift gears per say, even though I am really steady with my cadence. It's kind of like my body operates at this band that is optimal (at least seems like it to me although what do I know) for me depending on the terrain or speed while staying at a relatively similar cadence.
 
So, I just had a thought about this as I was re-reading it. Maybe someone who knows more about mechanics can chime in here as well. Is it possible that those whose cadence stays steady no matter the pace, maybe they operate kind of like a CVT (continuously variable transmission). Basically to my knowledge (I'm so not a mechanic so this is really dumbed down) these types of transmissions actually don't have gears per say, but operate on a band or something so they continuously "float" in the optimal range. It's like a snow cats (snow machine, snow mobile, what have you) transmission. This is kind of how I feel when running, that I don't really shift gears per say, even though I am really steady with my cadence. It's kind of like my body operates at this band that is optimal (at least seems like it to me although what do I know) for me depending on the terrain or speed while staying at a relatively similar cadence.
Nick, I think the analogy is good, but doesn't necessarily support a constant-cadence approach to running. In the CVT diagram below, think of n1 as stride rate, and n2 as stride length. The optimal isn't necessarily reached by holding one constant, but by varying the two until either peak fuel economy or peak power production is reached.

A further complication for the analogy that I can see, is that a motor produces energy for one movement (which is transferred to other components through gears, belts, or shafts), whereas our legs are using energy for both muscle activation, to get the limb to rotate through its phases, as well as to apply force through hip extension. The idea is that some runners may favor one or the other--rate versus power--but everyone uses both.
GearBoxRotRotVar.gif

 
That is a great picture BL. I wish I could explain myself better, but for me I notice that say when just starting up a steeper hill my cadence does for maybe two seconds increase, then it flattens out back to the previous cadence (rpm) like the cvt analogy. Somehow I am able to adjust power or whatever so that my cadence stays the same except for that brief second or two. Like I said, I wish I could explain myself better.
 
That is a great picture BL. I wish I could explain myself better, but for me I notice that say when just starting up a steeper hill my cadence does for maybe two seconds increase, then it flattens out back to the previous cadence (rpm) like the cvt analogy. Somehow I am able to adjust power or whatever so that my cadence stays the same except for that brief second or two. Like I said, I wish I could explain myself better.
I understood your explanation fine. You must be one of those who is what I've termed 'rate-dominant' and adjust speed purely through power. According to what I've read, some runners are like you, others rely much more on holding force application constant while increasing/decreasing cadence to adjust speed, but most use some combo of the two. I think caution is therefore in order when telling someone that they must run at a specific cadence without knowing what kind of runner they are, unless, as has been pointed out by Jason, Willie, and others, they are over-striding, in which case forcing a higher cadence at the same pace will necessarily lead to a shorter stride. I think perhaps also, if someone is experiencing too much impact and/or knee or hip soreness, then perhaps forcing a higher cadence might help too. I just don't think the 180-rule should be applied unthinkingly.
 
This doesn't mean that I'm necessarily over-striding, but rather I am able to deliver sufficient force with each stride to propel me along at 10mm pace with a relatively low cadence of 162-4..

Welllll.... don't get exasperated with me, Lee, but it seems like you're descriping a kind of "loping gait", involving excessive vertical bounce which translates to wasted energy and unnecessary impact. And in the barefoot framework, you're quite possibly adding the dreaded "push-off" into the mix.

But if you're running happy and free and feel fit and fine, then that's all that counts! :D
 
Welllll.... don't get exasperated with me, Lee, but it seems like you're descriping a kind of "loping gait", involving excessive vertical bounce which translates to wasted energy and unnecessary impact. And in the barefoot framework, you're quite possibly adding the dreaded "push-off" into the mix.

But if you're running happy and free and feel fit and fine, then that's all that counts! :D
Thanks Willie, good things to be aware of. I only get exasperated with sterile debates in which one or both sides bring preconceived notions and/or agendas and refuse to consider the opinion, or whatever evidence, the other side proferrs ;) . Constructive comments or criticisms are always welcome, and that seems to be the general tone of this site/society.

I'm about ready to head out for my run, so I'll try to proprioceive bounce and push-off as you suggest. I'm pretty sure I don't 'bounce' because I check myself out in store windows once in a while. Push-off will be harder to objectively observe, but the fact that I don't get abrasions is a good sign, right?

In any case, I think it's important to keep pace in mind with any sort of evaluation of cadence. At a bit over 6'1", and with fairly strong legs, I think my 162-4 stride rate may be perfectly normal for 10mm pace, which is my slow pace on smooth, flat surfaces. By 7mm or 7:30 mm my cadence picks up to 180, and so presumably it would be in the 190-200 range if I approximated elite marathoners' pace. So I don't think it's out of line to assume that if my form is fine once I hit the magic number of 180 at 7mm pace, that it's probably OK at 10mm and that lower cadence is an effect of lower pace and not of deteriorating form at slower paces. This also jibes with Hutchinson's data (http://sweatscience.com/the-problem-with-180-strides-per-minute-some-personal-data/). I'm also pretty sure my cadence picks up on rougher surfaces, which I would take to be a good sign, if true, that I'm making proper, mostly unconscious adjustments. One day I should just go out an check out all the variables, but today's goal is to see if I can maintain 9mm pace for 7 miles, so I don't really want to mess around too much with other stuff. Maybe on Tuesday's run. Thanks for the feedback.

I did find it interesting when I watched Dr. Mark's video again before sending it off to a friend who's trying BFR at my behest, that he states 180 is when everyone achieves peak efficiency. It's interesting, because he's a doctor and so presumably isn't just parroting the misunderstood Daniels quote about 180 being optimal because he happened to observe elite runners with good form at or above this cadence while running twice as fast as your average recreational runner.

Also, I took a peak at RW's BFR site this morning, and there too is a thread on cadence, and it was interesting to observe that a lot of people there subscribes to the 180 rule as dogma, whereas here people either don't subscribe to it, find themselves unconsciously gravitating to it, or have consciously employed it to overcome overstriding or bad form, but that fewer accept it as a hard, fast rule than those over at RW.

I was wondering, do you notice a difference in culture among the barefoot runners at RW from those who participate here, and if so, what are the differences, in your opinion?
 
Lee ,

""""However, there is no single optimum value for cadence. The optimum cadence depends on one’s ability to exert a well timed strong push.""""

I can agree that there is no one single value for cadence. The reason why however is different from the above comments from Canute. I absolutely disagree that it has anything to do with an active or forceful push off.
 
Lee ,

""""However, there is no single optimum value for cadence. The optimum cadence depends on one’s ability to exert a well timed strong push.""""

I can agree that there is no one single value for cadence. The reason why however is different from the above comments from Canute. I absolutely disagree that it has anything to do with an active or forceful push off.
Opinions vary I guess. But I like the fact that Canute understands science. Gives him an edge ;) .
 
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Knowledge of science very valuable many things but I rarely give it the edge over personal experience :) Let's just say I am not jealous or intimidated by his knowledge of science....but we are getting off topic now ;-)
Ya, there's an art as well as a science to running, and you are no doubt quite strong in the former.

I found it interesting that Canute acknowledges, in another post, that the Pose method's emphasis on high cadence and lift may work quite well for injury-prevention, which has been my hunch as well.
 
How about a bouncing ball analogy? This might be a bit crazy, but consider Dr. Mark where he says that with proper form, 75% of the spring energy is returned. I was thinking a lot about cadence based on these threads and I kept thinking of a rubber bouncing ball where it compresses on landing and then springs back up. The lower the height the quicker the bounce or cadence and the shorter the time it contacts the ground. I also read another article that stated that they did tests between two runners with equal V02 max, but one ran faster than the other by quite a bit. They contributed it to a slight difference in how ones center of mass moved up and down by a few centimeters more than the other.

So would it be valid to say that the higher one’s center of mass moves up and down the slower the cadence and the longer the ground contact time?

-Jim
 
So would it be valid to say that the higher one’s center of mass moves up and down the slower the cadence and the longer the ground contact time?

-Jim
I think that is correct, except the cause and effect are reversed. The higher the cadence, the less ground contact time (time in stance), and the less time airborne, so less movement of the CoM. Minimizing movement of the CoM may or may not be a good cue to achieve higher cadence, but I don't think it can be causal.

You can see in this clip of Usain Bolt that he bounces more during his lower velocity/cadence victory lap (which is still fast by most of our standards) than when he's all-out sprinting.


There are basically three energy costs in running: limb movement, push to achieve lift, and overcoming the braking of landing. A higher cadence can decrease the energy expenditure of the latter two, but increases the energy spent on the first. So at any given velocity/pace, there will be an optimal cadence in terms of efficiency that minimizes overall energy output of all three components in combination. Some have argued that the unconscious is far better at determining this optimal value than conscious manipulation, since there are so many factors involved, many of which are not immediately available to conscious perception, although various coaching cues may indirectly bring them to awareness. Conscious manipulation, on this account, should be confined to form issues, not stride length, stride rate, or strength of push (although the timing of the push can be productively refined, as a form issue).

However, by increasing cadence, and therefore reducing push per step, one will experience less ground reaction force, which may help prevent injury. So there may be a trade-off between optimizing efficiency and optimizing injury-prevention, although there may be injury risks involved in a higher cadence which haven't been taken into account in this model. As someone who has a pretty strong push, and who has experienced problems with stress in his metatarsals, I'm thinking of trying a slightly higher cadence than feels natural to see if this doesn't help prevent stress reactions, since efficiency is not a concern. Indeed, a less efficient run would be a better workout.

In any case, glad to talk to a fellow running geek.
 
Lee,

"""""""There are basically three energy costs in running: limb movement, PUSH TO ACHIEVE LIFT, and overcoming the braking of landing"""""""

Could you expand your thoughts on what you mean by PUSH TO ACHIEVE LIFT? is this push active or passive? something we need to be thoughtful of at each step? Something that just happens as a result? etc...... My description of the energy costs would be: leg recovery, vertical movement of the GCM, and the support/landing/ground contact time. Are we saying the same thing?
 
Lee,

"""""""There are basically three energy costs in running: limb movement, PUSH TO ACHIEVE LIFT, and overcoming the braking of landing"""""""

Could you expand your thoughts on what you mean by PUSH TO ACHIEVE LIFT? is this push active or passive? something we need to be thoughtful of at each step? Something that just happens as a result? etc...... My description of the energy costs would be: leg recovery, vertical movement of the GCM, and the support/landing/ground contact time. Are we saying the same thing?
I think we are saying the same thing. I haven't invested enough time in this to adopt a more exacting and consistent technical vocabulary. Ideally, I would read up more on mechanics/biomechanics. As for pushing to achieve lift, of course it is active, in the sense that the muscles are activated, but largely unconscious for most of us. However, somewhere on Canute's site he quotes Usain Bolt as saying that when he runs, basically all he thinks about is push, push, push. For slower paces and/or longer distances, it might not be necessary to think about this aspect of the gait cycle at all.
 

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