The Running Gait, Part 1: Contralaterality

All gait is a contralateral movement. Although It seems like the most obvious statement (perhaps to the point of being boring), it often astonishes me just how unexamined it remains. Discussing both the theoretical and practical implications—what it means for our training—is what this series of posts is all about.

To say that a movement is contralateral is to say that when something happens in one side, the opposite will happen in the other side. During gait, if our left leg moves forward, our right leg moves back. But our gait is also reciprocal, meaning that the limbs in the same side move in opposition to each other, to balance their movement. If our right leg, supporting our body during the stance phase of gait, moves back, our right arm swings forward in a passive motion meant to balance out this movement.

This kind of reciprocal action is very similar to the kind of activity that you find in a lot of modern machines. Let’s take the internal combustion engine as an example. To make this simple, let’s look at a flat twin engine like the one mounted on a lot of BMW motorcycles:


In the image you can see two pistons, each moving in opposition to each other around a crankshaft. This movement is—or should be—a lot like the movement of the legs around the hips. By the way, this imagery isn’t just a metaphor: there are important similarities between the mechanics of the piston system and the mechanics of the hips and legs.

I liken the lowest point in the piston’s rotation to when the leg (the right) is in swing (1). The apex of the piston’s upswing corresponds to midstance, where one leg (the right) is fully supporting the body (2). At the same moment, an opposing piston must be in the lowest point of its downswing in order to balance the mechanism.

Piston Mo
By Zephyris – Own work, CC BY-SA 3.0,

Any problems in the balance of the pistons or the crankshaft can cause something to go horribly wrong. The same goes for the body, in order for its movement to be in balance. As the left leg clears the ground behind the body, the right (opposite) arm must be ready to initiate the upswing. And the right leg should be ready to start reaching for the ground below.

Insofar this is the case, the movement can be said to be contralateral.

Let’s look at the pictures of Mo again (taken as he is sprinting down the final stretch of his gold-medal performance in the 10,000 meter event of the 2012 Olympics). As you can see from the right arm in (1) and the left arm in (2), both pictures are taken at the same moment in gait (from the frame of reference of the arms).


By comparing both pictures you can see a bit more flexion in early stance for the left leg (1), than for the right leg (2). At this moment in gait, the right leg trails further behind the body (1) than the left leg. (The left calf (1) is also at a larger angle than the right (2).) Without getting too far into the mechanical details, it would seem that Mo’s having a little bit more trouble stepping forward with the right leg than with the left.

In effect, in picture (1) his left leg is flexed because it’s waiting for the trailing right leg to catch up. And if you look at the orientation of his forearms, you can see that the right elbow (1) is far more flexed than the left (2), mimicking, to almost a perfect degree, the angle of the opposite knee in each of the pictures.

The point is that it wouldn’t matter where you look at the piston system (of an internal combustion engine) from. Whether you observe the piston system from the frame of reference of the piston head, the main axis of the crankshaft, or the counterweights, you would see that the entire system is balanced. Each counterweight remains perfectly opposite to a piston, and the pistons remain perfectly opposite to each other.

This is so important that much of what makes sports cars—particularly “traditional” sports cars like Ferraris—and race cars cost as much as they do is the technology to keep the engine block balanced to the picogram. The better this is accomplished, the more torque can go through the engine without breaking apart the block.

Mo Farah is not some amateur. For the past few years, he has set the highwater mark for excellence in distance running up to the 10,000 meters. And even then there are differences.

Why is this happening? The “big” answer to this question probably isn’t in some esoteric discussion of biomechanics. Quite simply, the 10,000 meters are run on an oval track, and this is the final stretch. For more than 24 laps, he’s been turning into his left leg. It’s probably a lot more tired than his right, so it’s having a harder time supporting his body during stance. (Hence the flexion).

If we asked Mo to keep running for a few more laps (not that he would) we’d find that his right leg would continue to trail a little more, and his left leg would flex even further. If you look at the video you’ll see that even down the final stretch he’s compensating quite well by driving forward with his right shoulder every step.

But as he becomes more tired, we’d see that this strategic compensation stops being enough. We’d probably observe his left foot taking increasingly longer to leave the pronation (flattening) that occurs during the stance phase. The supination (pointing) which occurs towards the end of the stance phase, would come too little, too late, possibly creating a heel whip for the duration of the race.

pronation & supination.png
Pronation and Supination

As this is happening, the huge amount of forces that go into his body as his feet strike the ground will travel through it at increasingly odd angles. There is a potent compounding effect here: The more experienced, fitter, and more rested body aligns itself correctly with the forces of running. The less experienced, less fit, and tired body does not.

For the weekend warrior with the New Year’s resolution, running a marathon is biomechanically a far more hostile experience than it is for the skillful runner. Some people overpronate from the get-go. Others start with a tight hip. Over the course of 40,000 paces, this brings nothing but disaster.

Physics favors the trained runner much like the Greek Gods favored the heroes of mythology, by further increasing their already formidable advantages in battle. The skillful runner already comes into the race with stronger muscles, denser bones, a more resilient nervous system, and a more robust metabolism. As a final reward for their training efforts, the impact forces of running fall into place and work with them, not against.


Strategizing Stress, Part 1

Training, like life, is a messy business.

I say this because lately I’ve been working with two excellent models of athletic training, Pose Method and MAF. Writing about them is the easy part. Applying them is more difficult. I recently ran across a very interesting case of a Pose/MAF enthusiast who wants to develop an aerobic base according to MAF principles, but has to sacrifice the correct form (a.k.a. running Pose) to do so.

(And ends up getting plantar fasciitis in the process.)

However, just because you get plantar fasciitis when you run at an aerobic intensity—which for most people means “running slowly” (OK, very slowly)—does NOT mean that you get to skip building an aerobic base. Building an aerobic base is important. And to ensure any sort of long-term well-being (particularly as an athlete), it’s necessary. One of the key functions of the aerobic system is to buffer and absorb the stresses induced by high-intensity activity.

In order to develop a good aerobic base, it’s important to stay at a low intensity. According to the MAF Method, the point at which you get the most bang for your buck out of aerobic base building is just under the MAF Heart rate (what researchers refer to as the “aerobic threshold”).

But a certain amount of energy is necessary to maintain good running form. If the aerobic system can’t provide enough energy, then your body has to work harder (increasing the intensity) and recruit the anaerobic system to provide the rest. When the aerobic system becomes relegated to its auxiliary function—processing the by-products of anaerobic exercise (lactate and hydrogen ions)—it will begin to break down. Two strategies help protect its health:

  • Allowing it to rest between periods of high-intensity activity.
  • Creating opportunities for it to be the main provider of energy for exercise.

So, when someone has to forgo the period of low-intensity training that we typically term “aerobic base training,” it becomes very important to strategize the stresses of exercise. On the metabolic side, running slow isn’t worth the plantar fasciitis it’ll create (in this case). And on the biomechanic side, we have to be careful that the stresses of running at a higher intensity don’t exceed what an untrained aerobic base can handle.

A safe way to do this is by taking a hybrid approach:

Combine 2-3 days a week of relatively easy Pose training (running+drills) with 2-3 days a week of walking, jumping rope 5 days a week anywhere from 5-15 minutes. While this isn’t really aerobic base training, it is still a way to develop (or at least maintain) aerobic fitness while taking steps to remain injury-free. While the Pose training is “higher intensity,” there are two options for how to manage it correctly:

  • Keep sessions short (read: fatigue-free) and high-intensity (threshold pace and above).
  • Do longer (also fatigue-free) sessions below the anaerobic threshold.

In regards to aerobic training: even if you walk quickly, you’re unlikely to come close to your MAF HR. However, you’ll still be able to develop aerobically at a slower pace. A better option, if you have the means, is to go doing moderate hiking with your heart rate monitor, which should put your heart rate a little bit closer to MAF, for the most part. I myself happen to have trails 5 minutes away from my doorstep (downtown!), but that isn’t the case for most of us.

Jumping rope will get your heart rate closer to MAF than walking. Another benefit is that it helps you train one of the key components of running: the Pose. The Pose is that snapshot of the running gait where one foot is on the ground, the other is passing under the hips, and the body is in a slightly S-shaped stance.

By jumping rope—or even better, (a) jumping rope while alternating feet or (b) doing simple Pose drills in the process—it’s possible (for a lot of us) to train the running Pose without going over the MAF HR. (Remember: trying to maintain the running Pose was the initial reason for exceeding MAF.) But after having practiced the running pose under the MAF HR, it’ll take comparatively less aerobic base training to be able to produce the running Pose at the desired, low-intensity heart rate.

How long will it take to develop an aerobic base that’s good enough to maintain a running Pose throughout a run? It really depends on the person: their metabolic and biomechanical starting point, lifestyle, and devotion to their pursuit of athleticism.


Running form and aerobic training

Training at a low intensity—often referred as “aerobic training”—is extremely important to allow the body a respite from the stresses of high-intensity training, and to develop the mechanisms that increase its resilience. We know that much.

But when training aerobically is our only focus, even during a period of “aerobic-only” training such as base-building, we may be hindering our improvement: improving our running form, by reducing the difficulty of running, also reduces the stress on our body. Because stress suppresses the function of the aerobic system, taking the time to develop our form hastens our aerobic gains.

The standard set by The Pose Method is the best example of “good running form,” as I see it. I fully adhere to the notion that pursuing a standard—the right standard—of running form is the quickest and surest way to reduce the difficulty and stress of running. But I also believe we don’t need to go as far as mastering the tenets of The Pose Method to reduce stresses and bolster our aerobic training.

This is because of a concept called “power leaks.” Running is all about moving the center mass of the body forward in a straight line. Some vertical and horizontal oscillation can’t be gotten away from. However, minimizing that up-down and side-to-side movement lets more of the body’s energy to go towards moving it in a straight line, and removes the need to spend energy balancing the body’s odd movements.

Power leaks, in essence, are those jerky movements that happen in odd places of the body—a sharp outward rotation of the knee combined with an upward collapse of the hip, which causes the weight of the body to fall to the outside. The body then has to recover, shifting its weight back in, to produce the next step.

When this extraneous weight shift and joint movement happens, the force of the footstrike travels through the body at an odd angle. Muscle fibers, and tendon and bone tissue are meant to move in alignment with the major force the body experiences: gravity, which pushes the weight of the body downward, and the opposite and equal ground reaction force the body experiences when the feet are on the ground. When tissue does not align with force, the likelihood of injury skyrockets.

“Stress.” is the body feeling that its likelihood of injury increases. Therefore, its defense mechanisms kick in. As a result, it does one of two things:

  1. It slows the body down in order to mitigate those forces to a comfortable level.
  2. It kicks up the stress response (and the heart rate), because it remains in a situation where there is a dangerous challenge to its physical integrity.

The increase in heart rate (and decrease in speed) is commensurate to the magnitude of the challenge.

Here’s the big lesson: if you want to reduce the body’s stress response to a particular task, increase its skill level.

Of course, there are myriad other stresses that conspire to wreck the body’s aerobic function: environmental, nutritional, even social. But the physical stress of poor alignment, due to the lack of skill required for the task, may be the larger part of the equation.

Running is an exceedingly complex task, biomechanically speaking, and it is performed by a full-fledged, multifaceted human, with imperfections and worries and commitments. Very few people have the privilege to be monks. Very few people have the privilege to increase their sleep, move far away from the chemicals endemic to the urban sphere, and detach themselves from the social preoccupations that come from being social animals.

But every one of us who has the time to run also has the time to perfect our running form. The problem is that few of us are aware that running form can be perfected, and that it is a way to reduce the stress of running. Misalignment is a real thing.

Alignment, or a lack of it, determines whether three astronauts get to return to Earth (or not). It determines whether our knees and hips survive the gauntlet of a hundred thousand steps we take during the marathon. It determines whether the body feels relaxed and competent when it analyzes its capability of performing a task.

“Aerobic training” isn’t the only way to approach the functionality of the aerobic system. Improving our form can do that too.