Why cadence matters.

A significant debate in the running world today concerns cadence. The question is: At which cadence should a person run? Some argue that the minimum cadence should be 180 steps per minute (spm), on the grounds that it is far more efficient than slower cadences.

Several important counterarguments have been made to this claim. One is that high cadences occur more often in elite runners, and then only during races (and that these same elite runners run at very low cadences during their warm-ups).

In this sense, nobody has ever run at one cadence—and indeed, there simply cannot be a “minimum” cadence: every run that anyone has ever run started out at a cadence of zero (when they were standing still) and their cadence slowly or quickly climbed to the cadence that they adopt habitually at a cruising speed. So, in “reality,” everyone has an infinite number of cadences at which they run: They start from a cold zero steps per minute, and pass through 0.0001 spm, 0.0002 spm, and so on, as they make their way past their habitual “cruise” cadence, up to their personal maximum.

The people who first prescribed a “running” cadence, when pressed on the issue of whether there is “one” running cadence, would almost certainly agree that people go through an infinite progression of cadences during either acceleration or warm-up. They would probably say that they didn’t mean that 180 spm was the sole cadence at which people should run (which is clearly impossible), but rather that 180 spm is the paradigmatic cadence of the human body—the cadence that these elite athletes warm up to (or should, if they don’t), in order to get the most out of their run.

(To be honest, I don’t know the rationale for 180 spm in particular as the cadence of choice—instead of say, 182 or 178 spm. I haven’t read anything about muscular dynamics that suggest that 180 spm is the optimum (or why it is). My belief is that the optimum would be somewhat dependent on the individual’s dimensions. I But it’s very clear that across individuals, 180 spm is a much more efficient cadence than 150 spm, for example.)

By this argument, why do high cadences show up the most in races? Because that’s when efficiency matters the most.

Think of this in the same way we describe “being awake.” We understand it to include a certain degree of alertness. We go through a spectrum of wakefulness from the point that we initially open our eyes and brush off the cobwebs to the point where we can be at the top of our game in a networking event.

It behooves us to define “full wakefulness” not at the point where we are not asleep, but rather, at the point where all the possible systems that contribute to alertness and cognitive function are up and running. If you can “get awake” but can’t brush off the cobwebs—implying that you can’t bring critical cognitive systems into play (or into play enough)—you’ve got a real problem.

Running works similarly. The main argument is that because these physiological systems create a higher degree of efficiency by producing a high cadence, it behooves us to understand “running” as including a high degree of activity of these physiological systems. (In these terms, “running-like movements” can occur at all cadences, but “running” occurs only at the full activation of these systems.)

Cadence increases efficiency because of its impact in a crucial neuromuscular process known as the Stretch-Shortening Cycle (SSC). When the foot lands, muscles all across the body are passively stretched. Then the muscles contract (or shorten) almost immediately, releasing the energy stored during stretching. This helps the leg recoil and be recycled into the next step.

The longer the interval between the initial stretching and the subsequent shortening, the more energy becomes dissipated in the form of heat. The longer the wait, the less mechanical energy available in the muscles and tendons at the moment of shortening.

At a low cadence, the interval between the stretch and the shortening is very long, meaning that a lot of energy is lost as heat (and efficiency drops). But as cadence increases, the interval shortens to the point that very little energy is lost (and efficiency rises).

I often write about how a new capability gives you twice the benefits you expect: For example, because of the improvement in efficiency that comes with a higher cadence, someone that runs a given distance more quickly is not only faster, but it takes them less energy to run the same distance. So the physiological improvements of proper training contribute to produce a much wider set of advantages.

The above shows yet more benefits: The energy that goes into stretching a muscle has to go somewhere: it can either get returned as elastic energy, or it can dissipate as heat. See the problem?

Even though I’m not aware of a lot of research on the conversion of elastic energy to heat, we can say this: the person with a longer stretch-shortening interval—who loses more stored mechanical energy as heat—has two problems, not one: As we discussed above, they have a lower energy return. But also, the additional heat creates a greater thermoregulatory load on the body.

So the runner with the faster cadence (usually the fitter and more skilled one) will not only be more efficient than the runner with the slower cadence, but they’ll also stay cooler. (And to top it all off, the fitter one is probably also the one with more developed cooling capabilities).

Just to be clear: if you’re fit and skillful, you’re also faster, more efficient, stay cooler and can cool down better, but if you’re less fit and unskilled, you’re also slower, less efficient, you get hotter and you’re not as good at getting rid of that heat.

Of course, none of this changes the fact that there is a curve that shows that people do in fact run at lower cadences at lower speeds, and at higher cadences at higher speeds. And it makes sense why they would: despite its benefits to efficiency, you don’t need a high cadence at a low speed. However, sticking to this descriptive reality of the world isn’t very helpful: the problem is that cadence has been shown to correlate more with absolute speed than with relative speed. This generally means that a relatively slow runner going close to their maximum speed will have a much slower cadence than a relatively fast runner going close to their maximum speed.

If we just go by the observed speed-cadence relationship (and let that iterate itself in every runner), the faster runner will always be more efficient. In other words, slower runners won’t get the chance to be efficient.

Good coaches try to get slower runners to run at a fast cadence to allow them to achieve a greater degree of efficiency (although the faster runner may have more overall efficiency due to other advantages). And by forgetting about speed (at least initially) and focusing on increasing cadence, it’s possible to accomplish exactly that.

In defense of the endurance running hypothesis, part 1: how we think about evolution.

The endurance running hypothesis is the idea that humans evolved primarily as endurance runners. The argument goes that the human physique evolved and took its shape and function from the primary adaptive pressure of persistence huntingthat of chasing down our prey until its body shuts down.

However, this hypothesis is not without its detractors. A significant amount of scientists provide an array of counterevidence to the endurance running hypothesis. (And the debate continues.)

Take for example the case of the human gluteus maximus (butt muscle). Lieberman et. al. (2006) claim that the human gluteus maximus evolved its shape and size due to endurance running.

However, another article in the Journal of Comparative Human Biology finds that the gluteus maximus grows much more in high-force sports (weightlifting) and high-impact sports (such as soccer), than it does in endurance running. In fact, they also show that the butt muscle in endurance runners is no larger than in the non-athlete population.

What I disagree with is their conclusion, which is paraphrased in the “What does this mean?” section in the image below:

“The human gluteus maximus likely did NOT evolve through endurance running, but through varied explosive and forceful activities.”

gluteus-maximus-size

My disagreements with the article (and the image) are primarily about how and why we interpret the science to mean a certain thing.

At first blush, the fact that endurance running doesn’t enlarge the gluteus maximus as much as other sports seems to detract from the idea that the muscle takes its shape from endurance running. But I think it actually adds to it.

By my analysis, these findings show that the basic, untrained shape and size of the gluteus maximus—it’s “factory specifications,” if you will—assume that it’s going to do the amounts of cutting, jumping, weightlifting, and sprinting that a habitual endurance runner might need to do. But it requires aftermarket modification to meet the (literally) outsize power and stability requirements of soccer or weightlifting.

Let’s say that a muscle evolved under a particular adaptive pressure. This means that its shape and size literally evolved to do that thing. If you take a muscle that usually doesn’t do a thing for which it evolved to do, and you ask it to do that thing, you are asking it to do something that it has prepared to do for millions of years of evolution.

In order to fit a function that it has been designed to do, the changes in shape and size that the muscle should have to undergo should be smaller, not larger. You would expect a muscle to change far more if you ask it to do something that is less aligned with its evolutionary job description.

Let’s illustrate this by looking at the arm and hand.

We probably all agree that one of the things that specifically sets us apart from our hominid cousins is the ability to coordinate the thumb with the rest of the fingers in order to grasp and manipulate objects to a high degree of dexterity. In its simplest form, this is the capability to oppose the thumb and the fingers—to make an “OK” sign with the thumb and each of the fingers of each hand.

Now let’s take a snapshot of the people who take this unique human ability to its very pinnacle: string musicians, graphic artists, etc. Their livelihood depends on the degree to which they can explore the potential of one of the major evolutionary functions of the human hand.

Compare the forearm muscles of a violinist or painter with that of a weightlifter. The weightlifter’s arms, hands, and shoulders will be much larger and more powerful. (I trust I need not cite a scientific, randomly-controlled study on the matter.) Why? Quite simple: weightlifters engage in activities that develop the body to phenomenal proportions.

But if we go by the conclusions of the article, the fact that the arm and hand get bigger through weightlifting would mean that it didn’t evolve for the kind of fine motor control that you produce in the arts. (Or that lifting heavy objects is its primary evolutionary role). A particularly ambitious version of this argument would be to suggest that one of the core functions of opposition is to become better able to lift heavy objects. But all these suppositions break down when you realize that our primate cousins were not only quite able to grasp branches and use them ably, but that opposition emerges at the same time that hominid arms were becoming smaller (and less powerful), not larger (and more powerful).

Of course, the human hand (and upper extremity in general) still needs to be able to grow and develop in order to be able to lift heavy objects—and can indeed grow to a huge degree to exhibit that function. But its core evolutionary function is to produce the unparalleled dexterity of the human being.

Furthermore, the fact that the non-painter’s hand remains relatively unchanged in size compared to the painter’s hand means that the non-painter’s hand is already relatively set up to perform that kind of dextrous function—because that’s what it presumably evolved to do. This should serve as evidence (not counterevidence) that the hand is primarily for painting (and other fine motor tasks), not for weightlifting.

We should think the same of the gluteus maximus.

Let me conclude by saying that nothing I’ve written here means that the gluteus maximus evolved exclusively for endurance running. Indeed, there is ample evidence suggesting that the architecture of the gluteus maximus is uniquely multifunction as far as muscles go. (In future posts, I’ll delve more into the nuanced view of the gluteus maximus that I proposed above: that it owes its shape and size to the fact that it is a muscle designed for the kinds of “varied explosive and forceful activities” that a bipedal, primarily endurance running animal expects to have to do.)

But what we can say is that the fact that the gluteus maximus gets bigger through a particular stimulus has no bearing on its core evolutionary role, (or on the evolutionary story of the organism as a whole).

Marathon Training, Part 1: Basic Requirements

When people want to know how to train for a marathon, they usually ask you for a training plan. This typically typically center around the following:

  • What kinds of workouts you’re supposed do.
  • How long those workouts should be.
  • How long you have to train before you’re ready.

Answering these questions is very difficult (if not impossible). Everyone is different, and begins their training at a different point. 

These questions are far too vague (or depending how you look at it, far too specific). It’s only a question that applies to you in particular. So instead of providing a training plan, I like to arrive at the issue from a different direction. The question I ask is:

How do you know that a body is ready for a marathon?

This question is much more useful. Why? Because being ready for a marathon is the same for every human.

The catch is that how to get there might be wildly different from one person to the next. For one particular person, your basic marathon training plan might be exactly what they need. Someone else may need to train for much longer, or with less intensity (or both). For yet another person, it might not include a crucial element that particular person needs—an element with which the training plan might work perfectly.

You’ll find that when you genuinely ask the above question—and truly inquire as to what it takes for a body to be physically and physiologically ready to run a marathon—you’ll inevitably conclude that ninety-five percent of the people who do cross the finish line of a marathon were not prepared to run the race.

I believe that one of the most important reasons that injury and illness is so rampant in the marathon is NOT because the marathon is inherently injurious, but rather because it is so physically and physiologically demandingand the vast majority of people who run it have not achieved the capability of meeting those demands.

A major goal of mine in life is that people do NOT get injured running a marathon (or any other race). And I believe that a first step in that direction is to help people understand what “being ready for a marathon” really means from a physical and physiological standpoint—beginning with the idea that there is such a thing as being “marathon-ready.” Only then can we genuinely expect ourselves—the individuals who constitute a modern athletic culture—to face a marathon with every expectation of success.

 I answer the question of marathon readiness in the following ways:

Biomechanic

In order to run at peak efficiency, you must be able to sustain a cadence in the ballpark of 180 steps per minute (spm). This is important because the critical systems necessary for maximizing running economy only become activated at around that cadence. For an array of biomechanic and metabolic reasons, it’s important that our definition of “running” includes the activation of these critical systems. The above means that to run a marathon:

Metabolic

It is said that 99% of the energy that you use to run a marathon comes from the aerobic system. This means that you must be able to run the race at an overwhelmingly aerobic intensity. How fast?

Putting the two together

The above two requirements, when put together, give us a third, “master” requirement:

  • You must be able to produce a cadence in the ballpark of 180 spm while running at a pace that is 15 sec/mile faster than your speed at aerobic threshold, and maintain it for the duration of the marathon.

A word on training load

There’s another way to look at this issue: how much someone needs to be able to sustainably train in a given week to be reasonably certain that they can run the race.

Sustainably means that there is no increase in stress, no nagging pains, and every reason to believe that the body can continue to train at that rate without injury.

So, a marathoner’s easy week should look like:

  • A volume of twice the race distance (50-53 miles).
  • An intensity that is exclusively aerobic (under the aerobic threshold).

*A good way to estimate the aerobic threshold without the need for a laboratory is by using Dr. Phil Maffetone’s 180-Formula. The 180-Formula produces the MAF HR, or Maximum Aerobic Function Heart Rate.

Sample easy week

All training is under the MAF HR, and cadence remains relatively close to 180 spm.

  • Mon    7 mi
  • Tue     9 mi
  • Wed    7 mi
  • Thu     9 mi
  • Fri       7 mi
  • Sat       12 mi
  • Sun     REST

Conclusion

There are no guarantees in life. But if you can run an easy week like this, I can be reasonably sure that you’re ready (or almost ready) to run a marathon. How to work up to this, and how to navigate the many pitfalls and angles of the journey, is the hard part.

Part of why I rarely give training plans or talk about these requirements—popular demand has essentially forced me to—is because you can’t really meet them if you haven’t ironed out all of the physiological, biomechanic, and neuromuscular issues your body may have.

(And again: that’s the hard part—and it’s the part that you can’t really address with a training plan.)

And even if the prospect of running a marathon has never been in your sights, once you do iron out enough of your body’s athletic issues, you’ll find that going on 25-odd mile, easy long runs every month has become a fact of life. You’ve become familiar with the distance—and the idea of running it a little faster with a lot of other people seems as simple as that.

(This post is about being ready for a marathon. How to become competitive at the marathon is, of course, a different question.)