Lets just end the heel strike debate right now.

malmo wrote:

silly old fossil wrote:

Malmo, THIS!!!!!

http://www.newbalance.com/performance/running/good-form-running

Particularly STEP 1....experiment with it yourself.

My gosh. You mean that there are others who regurgitate an unproven hypothesis as proof that the hypothesis is true?

I particulary like this one "Lean forward, gravity will pull you forward."

No, the leaning forward made you go forward. Gravity can only pull you down.

Malmo, I am kinda ambivalent about Steps 2 through 4 myself, but Step 1 is gold. Step 1 pulls your hips forward into the correct alignment for running effectively. I told you previous that posture is important, at least IMHO.

And, posture deteriorates with age.

wilfredo wrote:

turkey leg wrote:

The force that pulls you forward is a result of gravity. Just as the wind is the force that allows a sailboat to sail into the wind.

It really is very relevant to understanding how a runner propels oneself.

no. it is nothing like wind pushing a sailboat. it is like gravity keeping a sailboat from floating into space. if you are on ice, gravity is not going to help you run. yes gravity allows there to be a frictional force, but this has nothing to do with heel strike or really anything. it's like saying you breathe air and you need to breathe to run, therefore air is the force that propels you forward

It has everything to do with it. As an example, imagine someone standing straight up and still facing a wall. There is no movement because the feet's center of pressure on the ground is directly below (in alignment) with gravity. Now, imagine the person leaned forward, by Z degrees from vertical, and supported themselves by pushing horizontally on the wall. The formula of the horizontal force of the hands pushing on the wall is:

Person's Mass * gravitational constant * sine (Z)

So you can see how the forward force that is created, which is the same that propels a runner forward, is a function of gravity and the amount of forward lean from the center of pressure of the foot on the ground. If gravity were zero, no forward force and movement. If the runner does not lean in front of the foot's center of pressure, no forward force and movement.

This also says that if pressure is applied from the foot to the ground in front of the center of mass, a negative horizontal force is created that puts the breaks on. In other words, more work will have to be done to move at the same speed.

How does this enter the heel versus forefoot striking debate? Well, as others have said, the body part doesn't really matter--only that whatever foot part that does the landing is not in front of the center of mass. This is fact. This is proven mathematically. From here, feel free to go where ever you like with your opinion of what is best. Supposedly, this is where Lydiard stopped, by saying "hips forward".

But I want to also point out that there is a likely a huge diversion of what people call a heel strike. I have a feeling that pro-heelers equate heel striking as the heel being the first to contact the ground; whereas pro-midfooters or pro-forefoots see that even though the heel may contact the ground first, it doesn't really apply much force to, or "strike" the ground.

I'm willing to bet that in a very good slow motion video that just about every successful "heel striking" runner continues to drop significantly (that is to say, does not apply much force to the ground to catch themselves) right after their heel contacts the ground.

It should also be noted, that if a large amount of force does go through the heel, that a large amount of torque enters the ankle because the heel bone is behind the bottom of the tibia. In that case, either the front of the foot is slammed into the ground (forefoot stress fracture?) or the front shin muscle has to do a lot of work (shin splints?)

This is absolutely ridiculous. You are not moving forward because of gravity, you are moving forward because you moved your chest forward, the rest of the motion is just rotation around a fixed point. Point. If you were standing on top of a swingset with your feet in boots that hold you to the the bar, then lean forward, is gravity now pulling you forward? No you will simply rotate around a fixed point, eventually moving 'backwards' due to the angular inertia, and continue to swing back and forth until you stop, UPSIDE DOWN, with gravity pulling you in the only vector direction it can - STRAIGHT DOWN.

WHY ON EARTH TO YOU CONTINUE TO ARGUE THIS POSE NONSENSE?

Only freaking stubborn idiots are framing this as 'pro-one-footstrike or another" I don't care one way or another becasue it simply doesn't matter.

This onus is on you. You're the one with the superstitious theories.

Lets me get this straight, if a large amount of force goes through the heel (when I don't believe happens anyway) this causes MORE energy to hit the forefoot causing stress fractures, and the shin muscle has to do more work, causing shin splints? Are you freaking out of your mind? You've already got one theory that has no proof behind it, now you want to add even more baseless speculation on top of that?

You are incredible.

How about this theory - maybe it makes sense that heelstrikers deflect 20 percent of the force of contact, therefore putting less stress on the web of bones in the forefoot, causing fewer injuries and a more efficient transfer of energy to the ground, therefore fewer and less severe injuries to bones and muscles of the lower extremities. I don't have any proof of that, but it makes a hell of a lot more sense than your idea that gravity causes you to move forward.

I thought everybody would like this: http://www.youtube.com/watch?v=tTO7tFiyBlw&feature=related

malmo wrote:

This is absolutely ridiculous. You are not moving forward because of gravity, you are moving forward because you moved your chest forward, the rest of the motion is just rotation around a fixed point. Point. If you were standing on top of a swingset with your feet in boots that hold you to the the bar, then lean forward, is gravity now pulling you forward? No you will simply rotate around a fixed point, eventually moving 'backwards' due to the angular inertia, and continue to swing back and forth until you stop, UPSIDE DOWN, with gravity pulling you in the only vector direction it can - STRAIGHT DOWN.

I didn't finish my thought. An if you didn't have your feet anchored to the top of the swingset you'd fall straight down.

There is bad physics being perpetuated by "turkey leg" and others and I can't bare to quote it. Took me too long to write this, so that several responses have since been posted, so let me start by iterating others that all this gravity pulling you forward stuff is utter crap. The "there wouldn't be friction otherwise" arguments are just sophomoric.

Here is the point: when you are running at a constant velocity, on average the net force on you is zero. This means that on average the upward forces balance the downward forces, and the forward forces balance the backward forces. The backward drag force pretty much dictates how much lean you need for a given pace, any more lean and you will fall over on your face, guaranteed. If you lean any more forward while running, it is true that you will speed up (accelerate) so that you don't fall over, but you can't maintain acceleration, so I promise that you will need to straighten up as you reach a new cruising speed, If you don't, plop, down you go. Secondly, as was already proven in a previous link, you cannot land with your foot directly below your center of gravity, you must land in front of it (again, I refer you to the biologist's study referenced way back in this thread, where he analyzed many elite runners' first contact point). If you continuously make first contact directly under your center of gravity, you will fall over and land on your face, guaranteed. It's basic rotational mechanics. How far in front is another question, which is where the "braking" and over-striding issues come in.

Add one more to the growing list of

Noureddine Morceli

John Treacy

Rod Dixon

George Malley

Paul Tergat

Alberto Salazar

Mark Nenow

Thom Hunt

Dan Dillon

Jan Merrill

Greg Meyer

Dathan Ritzenhein (being fixed or being f***ed depending upon your reality)

Mebrahtom Keflezighi

Abderrahim Goumri

Abebe Bekila

Abdi Abdirahman

turkey leg wrote:

Person's Mass * gravitational constant * sine (Z)

So you can see how the forward force that is created, which is the same that propels a runner forward, is a function of gravity and the amount of forward lean from the center of pressure of the foot on the ground. If gravity were zero, no forward force and movement. If the runner does not lean in front of the foot's center of pressure, no forward force and movement.

This is absolutely ridiculous. You are not moving forward because of gravity, you are moving forward because you moved your chest forward, the rest of the motion is just rotation around a fixed point. Point. If you were standing on top of a swingset with your feet in boots that hold you to the the bar, then lean forward, is gravity now pulling you forward? No you will simply rotate around a fixed point, eventually moving 'backwards' due to the angular inertia, and continue to swing back and forth until you stop, UPSIDE DOWN, with gravity pulling you in the only vector direction it can - STRAIGHT DOWN.

WHY ON EARTH TO YOU CONTINUE TO ARGUE THIS POSE NONSENSE?

Wow, Malmo. You're lack of physics knowledge is unbecoming. If you want to refute the rest of what I said, fine, but this part and my next paragraph is mathematically proven. That we use gravity to create forward force and movement.

In my example, I was comparing the two static states. In the forward leaning position, just as we are when running, the forward force that we have created is a function of gravity. What is ridiculous about this?

And for the record, I don't know anything about Pose so I can't argue for or against that, and never mentioned it either.

In your swingset example, do you see that the person moves forward while the vertical force on the swingset is downward, as it is on the ground? When the person rotates below horizontal, the vertical force on the swingset changes signs and results in a similar sign change of the horizontal force.

A more useful point is considering the monkey bars, staying with the playground theme, that is exactly like running. The person can use a slice of the phase of the rotation when the person is above the bar.

turkey leg wrote:

Wow, Malmo. You're lack of physics knowledge is unbecoming. If you want to refute the rest of what I said, fine, but this part and my next paragraph is mathematically proven. That we use gravity to create forward force and movement.

Unbelievable! Gravity doesn't causue forward movement. PERIOD. The fact that you lean forward and start rotational movement around a fixed point (your foot) doesn't change that. This is the same nonsensical talk that high school physics students say when the first learn that an object that is moving in a circular direction is accelerating, and their equate acceleration as being the same thing as straight line changes in velocity. Their next conclusion is that an object in rotation is constantly getting faster. "It's accelerating so that means it's getting faster. I learned that in physics." It's not.

I completely agree about the balance of forces. However, the WIND RESISTANCE necessitates a net forward lean. When one straightens up, only deceleration can occur from the wind resistance.

If what say is bad physics, maybe you care to educate me on how we create forward movement without using gravity?

i understand that you can't run without gravity, but that doesn't make it a driving force in any way. YOU DON'T NEED TO LEAN FORWARD TO RUN. by your ridiculous logic you would go backwards by leaning back. you can run forward while leaning back. that alone invalidates your entire argument.

wilfredo wrote:

i understand that you can't run without gravity, but that doesn't make it a driving force in any way. YOU DON'T NEED TO LEAN FORWARD TO RUN. by your ridiculous logic you would go backwards by leaning back. you can run forward while leaning back. that alone invalidates your entire argument.

hahahahahahahaha

I suppose you mean leaning as just the angle of your back? Because that is meaningless. Only where the center of mass is in relation to your center of pressure on the ground. It is impossible to move in any other direction than the direction the center of mass is from the center of pressure, speaking in plane view.

If you don't believe me, lean back into a wall and try to go forward.

Gravity is certainly not pulling anyone forward (unless the sun and the moon for some reason is right in front of you). The forward forces is entirely from friction. Of course you can get forward with no gravity (you just have to be careful not to take off). And increased gravity on earth would certainly make it cost more energy to run at the same speed.

However these facts have very little to do with the discussion of running form. I believe it is very individual as different people have different physiology, tendon stiffness, relative different strength of muscles etc.

I remember seeing a video where it is very clear that El Guerrouj is a heel striker, but cannot find it. Anyone got a link?

Physics PhD,

Please elaborate how you can get down a track without gravity.

Same principle as climbing a vertical wall. It is very much possible even though no external force is pulling you to the wall.

Of course with an idealized (friction proportional to surface pressure), perfectly smooth and nonadhesive surface it is impossible. However such a surface do not exist in our physical world, it cant even be constructed in theory.

On a rubber track with spikes i believe it wouldnt be too hard after some training (but i have not tried so i could be wrong).

In my opinion, there is absolutely no difference in midfoot or forefoot strikers. It doesn't matter at all which one you strike on. Midfoot, in some way, is actually more effecient.I do a mixture of midfoot-forefoot. Used to run much more up on my toes than I do now. Now I'm doing a combination.

Heel striking, on the other hand, fits people with weaker foot strength. I do not believe it is as effecient as the other two, and probably causes a little bit more injury, but I think if you change it then your subject to doom.

So In my opinion, unless your young, don't mess with your footstrike unless you naturally do all 3, something I can do but usually don't heel strike. In that case do midfoot or forefoot.

Another mention is that people need to relalize the difference between midfoot and heel striking. When people strike with both their heels and balls of feet at the same time, that is called midfoot which is what a large portion of the eltes do(about 1/3). So don't mistake the two.

turkey leg wrote:

If what say is bad physics, maybe you care to educate me on how we create forward movement without using gravity?

Think about it this way. You can't breath without gravity either (unless you use a tank), but that doesn't mean gravity is what makes you breath. Gravity is just the backdrop underwhich we must function.

Contraction of muscles against static friction is what causes locomotion. There is not a one-to-one correspondence between static friction and gravity. The maximum amount of static friction that can produced is proportional to the normal force, but that only dictates how fast you can accelerate without slipping.

As I said, you do lean forward slightly to combat the drag force, but that about it, and it ain't much. If leaning forward were so important, running on a treadmill would ruin your form. Think about that.

Running a treadmill does ruin my form.

And to Malmo:

I've suffered a few cases of PF and some self inflicted pain like you snd obviously some severe knee strains but really not much other than that.

To your list of successful elite heel strikers i think you can safely add the following:

Herb Elliot

El G

Abubaker Kaki

Lasse Viren

Miruts Yifter

Vebjorn Rodahl

Joachim Cruz