Conclusion on Arms

As I said before there are 8 different combinations. But there are also an infinite number of degrees to which each can be done. Here is a compilation of how each one effects running.

1. Timing - Leading with the arms speeds stride rate, causes the foot to land farther underneath the body and leave the ground faster.

Timing ahead of legs = fast stride rate
Timing with legs = neutral stride rate
Timing behind legs = slow stride rate

2. Arm length - A greater difference in arm length causes a greater bend in the torso which adds power and extends the stride length.

Arms longer moving backward = longer stride length
Arms same both directions = neutral stride length
Arms longer moving forward = shorter stride length

3. Arm angle - A greater inward angle in the arm swing towards the body's center line has a twisting impact on the torso when the timing leads the leg cycle, but it has no impact when it is in a neutral timing or lagging behind the leg cycle.

Arms swinging inward = no impact unless the armswing leads the leg cycle. If arms lead leg cycle, it adds power(force) but impeeds speed via range of motion. Great for up-hills or pulling a weighted sled.
Arms swinging straight = does not add power, but does not impeed speed either. Legs move freely. Great for down hill running, flat traeadmill running (no wind resistance), and running with a back-wind.

I believe if these three elements can be understood for what they do independently of one another, then the best combinations can be used for various running conditions. For example, to increase stride rate and stride length and transferring power through the legs from the torso, (1) lead with the arms (2) while lengthening the arm length on the back swing and (3) swinging the arms halfway between parallel to running direction and across the body. Stride rate comes from 1, stride length comes from 2, and the power to sustain that form at higher speeds comes from 3.

Alternative Arm Swing 2

In the last two entries we've covered changing the timing of the armswing in relation to the legs, and changing the arm length in the backswing compared to the arm length on the front swing. This entry will cover the swing angle.

Most runners are told "Move your arms straight forward and backward parallel to the direction in which you are running." No explaination of why, or how this is beneficial, so in this final entry on arm swings, let's talk about my two favorite questions. "What does it do" and "When would I want that to happen?"

Go for a run and swing the arms straight forward and backward as recommended. Then begin to swing them inward toward the center line of your body. How is this changing your running form?
Try it while leading with your arms (like discussed in the first article on arms) and do it while changing arm length (like discussed in the second article on arms) and do it while both leading and changing the arm length. What does it do?

I've noticed that when I lead with the timing of my arms and begin to cross my body slightly with my armswing I experience a twisting motion in my torso along the transverse obliques. When I move my arms back to moving parallel to the direction I'm running (just straight forward and backward) this twisting goes away. So, when would I want to use this?

Apparently, according to my experience, leading with the timing of the arms while swinging the arms across the body and causing the torso to twist at the transverse obliques has a significant impact on uphill running. This includes stairs as well.

Go out an experiment with combinations of the three elements of the armswing.
1. Timing with the legs (leading, following, or at the same time)
2. Lengthening the arm on the backswing and shortening it on the front swing
3. Swinging them forward and backward or at an angle towards the center of the body.

This makes 8 different possible combinations of arm swings in relation to th legs and they all work best under slightly different circumstances.

Alternative Arm Swings

We just talked about changing the timing of the armswing in relation to the leg cycle. But what about changing the arm length, or even the muscles used to initiate the arm cycle?

When a cheetah runs (granted, it's front legs touch the ground and ours do not), their front legs are straighter when they are moving backwards, and they are tucked under the body when they are moving forwards. So I tried this with my arms.

As one arm straightens out and moves backwards, the center of mass of that arm moves farther from my shoulder joint. At the same time, the opposite arm is shortening and moving forward which causes its center of mass to moce closer to my shoulder joint. What does this do?

First of all, I notice that my body is forced to bend laterally at the thoracic spine like a side crunch. It leans towards the side of my body with the shorter arm, and away from the side of my body with the longer arm. What does this side-crunch of my body do?

This side-crunch of my body has an impact on my legs. Basically, when I'm airborne, moving my upper body left and down causes my lower body (including my legs) to move left and up. Since it is the left leg that will be touching the ground next, this actually improves my air-time and slows down my stride rate. When would I want this to happen?

As mentioned in the last entry, improved air-time and a slowed stried rate is associated with downhill running.

Conclusion:
So, if changing the length of each arm causes my torso to bend side to side and is good for downhill running, might I conclude that the best strategy for uphill running is to do the opposite? To have both arms with a very similar bend in the elbows? And what about flat running? Perhaps an intermediate amount of lengthening and shortening with the back and front swing.
Try this and experiment. See how it works.

The Arm Swing

So, if you've been reading my posts, I try not to say what is right and wrong when it comes to running. In fact, thats my whole philosophy on life. Instead, I ask questions like, "What does it do?" and "When would I want that to happen?" And the armswing on running is no different.

Most runners will time the arms and legs together. In other words, left leg goes back, right arm goes back. Left leg stops, right arm stops. Left leg begins moving forward, arm begins moving forward. They begin and end movement at the same time. So, what happens if you change that?

If the arm swing begins slightly before the front foot lands, instead of simultaneous with it as is popular, I've noticed two things. First of all, since the arm swing begins while my whole body is airborne, that small transfer of mass in my upper body actually affects my legs by bringing my landing foot more underneath my body, and my trail foot less behind my body. This actually gets me into the acceleration position as described in the entries on the legs previously. So when would I use this offset timing in the armswing?
1. When I'm running uphill
2. When I want to accelerate

After this finding, I tried the opposite by letting the timing of my armswing initiate a split second after my front foot lands. This backward offset timing caused my foot to land farther in front of my body with my trail leg staying farther behind, and had an overall slowing effect. But it had another effect too. It increased my hang time in the air. So, when would I use this reverse offset timing in the armswing?
1. When I'm running downhill and trying to maintain speed
2. When I want to decelerate after a race or an interval.

The next entry will include more information on different types of armswings.

The relationship between the two legs in running (Part 2 of 2)

So what is the relationship between the legs in running?

To keep the body torso balanced - as when standing - the center of mass of one leg has to be an equal distance in front of the body's center of mass as the other is behind.

Take-Off phase

So the point at which the leg on the ground is at its farthest behind the body's center of mass (just before take-off), the other leg's center of mas has to be equally far foward to keep the torso balanced.

After the back leg leaves the ground, its center of mass continues back just a few more inches and the heel begins to rise. So the center of mass of the front leg should continue moving forward as well if our goal is to keep the torso vertical. This is easy to accomplish. While the back leg is getting read to leave the ground, the front leg should have its heel tucked. The knee is up and forward, but the heel is under the butt. So to get the center of mass of the front leg to move forward more, all that needs to happen is for the heel to drop and move under the knee. Notice that the lines under the yellow dots in the figure to the left are farther apart than the figura above, yet they are still equidistant from the line under the blue dot.

Flight and Foot Strike

In efficient running, the foot strikes the ground almost directly under the body's center of mass (actually slightly in front, but does not becoem fully weight bearing until it is directly underneath). This means that the front leg's center of mass will have to move backward during the flight phase towards the body's center of mass before making contact with the ground. Consequently, this means the trail leg will also have to move towards the body's center of mass while in flight.

I see recreational runners (heel-strikers mostly) with the trail leg way behind the body through the whole flight phase. For them, bringing the trail leg under the body's center of mass before landing will reduce breaking forces (including shin-splint inducing forces) and cause them to run faster and more fluently.

Foot Strike and Stance

In efficient running, again, the foot strikes the ground almost directly under the body's center of mass. In truth, it becomes fully weight bearing directly under the body's center of mass. So, when the front foot is about to touch the ground a portion of that leg will actually be in behind the imaginary plane (vertical from the body's center of mass) and a portion will still be in front of it. Therefore, the trail leg should have a portion of it in front of that imaginary plane before the foot strike occurs with only part of it remaining behind the center of mass. So the knee, the lower femur, and upper shin should be in front of the plane and the lower calf, foot, and upper femur and glutes should be behind.

This is the relationship between the legs in running at a CONSTANT speed: the center of mass of one leg should be exactly as far in front of the body's center of mass as the other leg is behind it at any given time during all phases of the running cycle.

During GRADUALLY ACCELERATING speed: the center of mass of one leg should be slightly MORE in front of the the body's center of mass as the other leg is behind it. OR, the center of mass of the trail leg should be slightly LESS behind the body's center of mass as the front leg is in front of it at any given time.

During GRADUALLY DECELERATING speed: the center of mass of one leg should be slightly LESS in front of the center of mass as the other leg is behind it. OR the center of mass of the trail leg should be slightly MORE behind the body's center of mass as the front eg is in front of it at any given time. This is why fatigued hip flexors and a tired core - which causes a delay in the initiation of the recovery of the trail leg - leads to a shorter stride and fatigued hamstrings.

The relationship between the two legs in running (Part 1 of 2)

Demonstration/Experiment:
Stand up straight and disect your body down the side to divide the front half of your body from the back half. This imaginary division should run perpendicular to the ground (straight vertical) and travel through your body's actual center of mass. Exactly half of your body's mass is behind this plane, and the other half is in front.

In the figure to the left, the red dots are joints and the yellow dot is the flexible portion of the thoracic spine just under the rib cage. I've made the stomach and chest cavity a bit thicker than the arms and legs to represent the fact that they contain more mass relative to their length.

When you lift the knee (like the knee drive in running) your whole leg moves in front of that plane (figure left). When it does, the mass of that leg changes your whole body's center of mass (from the line under the blue dot, to the line under the yellow dot) so that you fall forward. If you don't want to fall forward, then you are forced move an equal amount of mass backwards to act as a counterweight. If you remain balanced above the same point over the foot, that mass has to come from your torso. The leg moved forward, part of the torso moved backward, and the balance point remained the same.

This is what happens when the body is balanced ABOVE a ground-based"anchor" (the body's source of stability). But when you are flying through space, as in running, there is no ground based anchor. The "anchor" becomes the body's center of mass and it is located just below the ribcage when standing straight.

So let's go through the above experiment again, but this time, instead of standing on the ground, anchor yourself near the center of mass just below the ribs. If you have a roman chair (for abdominal exercises) you can suspend yourself on the elbows while your feet dangle below.

In this model (figure left), the axis point is not the foot, but it is the center of the body. So when the knee is lifted and the mass of the leg moves forward, the whole body rotates forward. Everything below the axis of rotation moves backwards (hips, legs) while everything above the axis moves forward (chest, shoulders, arms, head). For every action there is an equal and opposite reaction.

From this position (one knee lifted and the other leg straight in line with the body while anchored by the body's center of mass), there is only one way to get the torso to be straight up and down again. That is to move the mass of the other leg an equal distance behind the torso as the first leg is in front.

In this last picture, the line under the blue dot is the center of mass for teh whole body while the lines under the yellow dots represent the center of mass of each leg (from the foot to the hip on each leg). Notice how the torso is vertical and the centers of mass of each leg are equidistant from the center of mass for the whole body. Since the figure is anchored at his body's center of mass (yellow dot under the elbow), the vertical position of the torso is completely dependent upon the centers of mass of each leg being equal distances from the vertical line under the blue dot.

Stay tuned to find out how this relationship applies to running.

Moving from "Proper" and "Right" to Understanding How the System Works

So I was on the Runners World forums the other day and I posed a question just to see how it would go over. The question was essentially designed to see if anyone understood the principles of running movements. I don't want to post the whole question here, but I'll give three different questions that kind of summarize what I was trying to get across. Basically, "what does the leg NOT on the ground offer to the one that IS on the ground?" Or "How do they relate to one another?" Or "What goal is the leg touching the ground supposed to be achieving and how does the other leg (and the rest of the body) assist that purpose? No one who responded to my inquiry knew or had any idea.

The most common response I got was "You're overthinking it." But no one could actually answer the question with any understanding. One response included this: "Try to be efficient with your form and things should work themselves out."

I know there is credence to the idea that our bodies will become more efficient on their own, but really?

There seems to be a lack of foundation in the running community. Ask anyone about running form and they will tell you what you "should" do or what is "proper from." But ask them why it is proper and no one seems to know. If they did know, they would proceed to tell you the purpose of that movement, which is exactly what I'm trying to figure out.

In the next post I'll answer my own question. Stay tuned.

A Strong, Flexible Spine

If a genuinely new technique is to be discovered in running it is going to be important to challenge conventional wisdom and widely accepted thought. For example, I have been studying cheetahs and, most of the experts agree, cheetahs are fast because fo their flexible spine which adds spring into each stride. But in speaking of people, they say we do not have a flexible spine. Or do we... http://www.youtube.com/watch?v=6NckIdFl9Is
I found this video on youtube. Instead of saying we don't have a flexible spine, maybe it is more accurate to say we don't know how to utilize a flexible spine.
According to the following video (refer to minute 2:33), "runners need powerful leg muscles for long strides. The muscles bring the leg down hard launching the runner into the air."http://www.youtube.com/watch?v=S-zcA_mOa94
Ouch! Can anyone say, "Shin-splints?"
Yet in the same video, Scott Edwards, Ph.D., a professor at Harvard, says that cheetahs don't, and can't, get their power in the same way. He says cheetah's legs are too light and fragile to do it that way. He goes on to say cheetahs carry 60% of their muscle mass on their spine. In other words, they have light legs with a freakishly strong core that mobilizes their flexible spine.
(refer to minute 2:55).
I say, if cheetahs are faster than we are, maybe we should be trying to lighten our legs and load up on our core strength in order to achieve a power output from the flexibility of the spine instead of by "bringing the leg down hard." If a centralized spring helps the cheetah achieve 75mph, maybe it can help us break 35 or 40.

Three Limits to the Fastest Mile

Around the time of the summer Olympics, people turn their attention to athleticism and begin to ask questions like, "What is the fastest mile possible?" In the early 1950's doctors believed it to be physically impossible to run under a 4 minute mile without one's heart exploding. Yet, Roger Bannister accomplished this feat in 1954. Once news about his feat got to Europe, there were at least 3 others who also broke the 4 minute barrier within a few weeks of his historic run. Today the projected limit is based on a graph that plots the world record times over the last 100 years. The curve of the line suggests that mankind will max out his potential near 3:39, just 4 seconds faster than the current world record. Is it possible to go faster? And I mean significantly faster. Like under 3:30, or even under 3:20!

There are three main factors that limit a person's maximum speed for the mile. They are technique, conditioning, and body type - which consists of things such as height and leg length.

Since body type is genetic and unable to be changed intentionally, we'll disregard it for now. That leaves us with technique, and conditioning. For the most part, the technique runners have used over the last 100 years has remained the same. Use the core to stabilize, the hips and legs to mobilize, and the arms to counterbalance. So taking that out of the equation as well, we have only conditioning to consider. And this is where 99% of our effort has been focused as athletes, coaches, and trainers. The question nearly every strength and conditioning coach and researcher has asked, and the one that is taking millions of dollars in research every year at major universities as well as Olympic training facilities is in regards to conditioning is, "How can we train our bodies to become faster, stronger, and utilize oxygen better?"

But, with advances in technology and the greatest athletic minds coming together on this subject over the last few decades, I believe we are reaching the limit of physical conditioning as well as is indicated by the fact that we are so close to the projected fastest possible mile.

So here are the facts.

1.With Olympics being held every four years since 1896, we have attracted the greatest athletes and most genetically diverse athletes together to find the best the world has to offer. We are probably not going to find a better suited miler without going to another planet since we currently have access to all the nations of the world.

2. With the best technology for optimizing training and recovery, we're near the limit of human physical conditioning.

3. We have been using essentially the same running technique for the last 100 years.

It is my belief that if we are to achieve a world record mile that is significantly faster than what we project to be the limit of human potential, it will be by focusing our efforts to a running style that is fundamentally different than the current paradigm; legs to mobilize, core to stabilize, arms to counterbalance.

It is my intent to discover a better technique that is not just a refinement of an old one, but is actually brand new and essentially different than the formula we use now... Core to stabilize, Hips and legs to mobilize, Arms to counterbalance.