Lets just end the heel strike debate right now.

stop the insanity wrote:

biggus dickus wrote:

Please define your usage of heel strike.

Yes. many elites will strike with their heel first, mostly due to dorsiflexion. You will not often see elites overstride, which also results in a heel strike. When you do, I'd bet most occurrences are due to fatigue and not what they would consider "text book."

Over striding (e.g. my definition of a true heel strike) is not the best way to run and you will typically see this is beginner runners that do need some "training."

I can't believe this. Heel striking is touching with your heel first. What else could it be.

Overstriding? Now there's something that's undefinable if there ever is. Overstriding is purely subjective. Heel striking is not.

As started they are 2 key situations referred to within this thread that both result in the heel striking first. VERY different.

Over striding IS much more clear, a foot landing significantly in front of your center of gravity.

This thread has averaged almost 50 posts a day for a week and a half. Remarkable.

Lorenzo the Magnificent wrote:

This thread has averaged almost 50 posts a day for a week and a half. Remarkable.

Even more amazing is that the OPs outrageous statement was refuted on the first page.

biggus dickus wrote:As started they are 2 key situations referred to within this thread that both result in the heel striking first. VERY different.

Over striding IS much more clear, a foot landing significantly in front of your center of gravity.

How much is significant?

HHH wrote:

biggus dickus wrote:As started they are 2 key situations referred to within this thread that both result in the heel striking first. VERY different.

Over striding IS much more clear, a foot landing significantly in front of your center of gravity.

How much is significant?

Almost on queue, predictable very predictable. Enough to have your lead leg nearly fully extended.

Hint: next you ask, what is "nearly"

This is not a careless blunder at all. Do you think that Lieberman made a careless blunder for representing Force in terms of 'bodyweights'. Please cite a physics book where bodyweight is a unit of force measure? It is a derrived measure of force. He unitized the force in terms of bodyweight in an attempt to normalize the data for a logical reason. There's nothing wrong with that. I did the same.

We know that the energy observed on the force plate is causing movement, but is reasonable to assume that the movement is the same, therefore it becomes an irrelevant constant. Δd could be 0.5 pigglywigglies or 17 gigondas, it doesn't matter. As I said, work is still proportional to the force applied.

If you apply any force of F to any object to move it any distance Δd for T seconds, that is an expression for power. If you increase either the F or Δd, or decrease T, or any other combination of those three inputs, then power increases. The corollary opposite is also true. ***

Also, if you increase Δd, or decrease T, with an unmeasured but presumably equal Force, power also increases.

…and you can do the same thing with an unmeasured but equal T as a constant.

Making any of the inputs in the power equation a constant, doesn’t change these relationships. It’s 7th grade math.

***(and if you increase either of F or Δd and increase T, you're going to have to know all three inputs to determine whether or not power increase or not.)

All of the forces of impact and "stiffness" are reflected in the readings on the force pad. Please show me where on these screen shots of the force plate videos are the “legs springs” not represented in the data?

Note the highlighted commentary in the image. What kind of scientist says stupid shit like this? If this is true then I've been hit with a hammer at 2x bw well over 80 million times. IF I've been hit 80 million times, then what kind of hammer hits a forestriker who has higher peak impact forces than the heelstriker?

One thing that occurred to me while watching these videos what that the forefoot runner and the heelstriker were the same person. I started thinking to myself, “what the hell is this shit?” So then I clicked on the accompanying video at the top, and lo and behold, that same guy WAS LIEBERMAN HIMSELF!

!

SO LETS SUMMARIZE THIS IN BOLD FACED TYPE. THIS WAS A STUDY THAT WAS FUNDED BY A NEW AGE FOOTWEAR COMPANY. ONE OF THE SUBJECTS IN THE STUDY, IMPORTANT ENOUGH TO BE THE ONE SHOWN IN FORCE PLATE VIDEO COMPARISONS, WAS THE HEAD REASEARCHER HIMSELF - A BAREFOOT RUNNING NUTJOB.

By the way, this whole topic is in an unproven area, so demanding proof is really a moronic request...

Wrong, if we cannot offer proof or convincing evidence then we should accept that we could well be wrong and that we have in no way proved the original dogmatic assertion that there is only one way to run correctly.

malmo,

no amount of formulae juggling will undo your barking and fabrications.

Again, you are marred by contradiction, much like dogs who make a lot of noise but have no teeth left to even bite a bone. And a toothless top dog is doomed.

The term new age used by you, the same person who coined "personal phisicality", says it all. The fact that you write, that you and Lieberman do the same "normalizing", says it all again. The fact that, in an earlier post, you state you do not see anything wrong with funding research, but then raise doubt, says it all again and again. The fact that you say you are not a coach but you dispense self-referential running advice - a whole summer of running to be lived in your name no less - The fact that you make no mention of a past thread on this board about that same research which was also participated by the researchers, says it again and again and again. The fact that you seriously address people as fools and nutjobs yet go as far as answering them and recalculating their data.

Are you alright?

Maybe you are a beta AI Running app which needs to be debugged. Or in fact, that is so advanced that it is debugging itself.

If I knew you in person, I might react differently to what you write. But based on your handle and the content of your posts, the information you generate is soaking in contradiction and hence useless.

On a positive note, your jack-in-the-box sense of humor can go a long way. I lolled pretty hard at the free hugs video you link to on the thread's first page. I honestly thought I was going to see you running.

Anyway, happy new year.

biggus dickus wrote:

biggus dickus wrote:As started they are 2 key situations referred to within this thread that both result in the heel striking first. VERY different.

Over striding IS much more clear, a foot landing significantly in front of your center of gravity.

How much is significant?

Almost on queue, predictable very predictable. Enough to have your lead leg nearly fully extended.

Hint: next you ask, what is "nearly"[/quote]

Pardon me for not accepting your logic as truth but when you throw out words like SIGNIFICANTLY and NEARLY to prove a statement that contains the word CLEAR, I think perhaps even you can see how people might not believe you.

Now, can you quantify your significantly or nearly statements so we can have an actual debate on over striding or is this another one of those 'In my opinion' situations where you just forgot to mention that it was your opinion and can't actually prove it?

Apart from a being a personal attack on Malmo, what is your point here? I can't decipher your rambling either. You minimalist cultists are a strange bunch. If someone doesn't believe you, just throw out a bunch of nonsense and when someone challenges that nonsense just make up some more nonsense to back it up.

No, actually it is my personal replying after malmo said I sounded like a fool.

If there is something in particular that you want to be clarified, ask and I will try again.

I do not consider myself a cultist anything. If that's what you as a Hash House Harrier think, you are entitled to.

Not in one post did I ask to be believed. For dialogue to work, people need to listen to each other.

Funny, you should fabricate that. Why? Readers might be confused.

wtf100+n wrote:No, actually it is my personal replying after malmo said I sounded like a fool.

If there is something in particular that you want to be clarified, ask and I will try again.

I do not consider myself a cultist anything. If that's what you as a Hash House Harrier think, you are entitled to.

Not in one post did I ask to be believed. For dialogue to work, people need to listen to each other.

Funny, you should fabricate that. Why? Readers might be confused.

So you actually don't have anything to contribute apart from the personal attack? Am I missing something?

Are you Malmo?

I have contributed some questions already. I like to read and listen more than posting to be right. Still, this is an interesting topic. Read the wtf posts in this thread. Some of my questions generated some answers which I am going to check on before i comment them ( what the lore of running says about heel striking - I dont have the book handy.)

I hardly got any answers from Malmo. And that might have generated some further contributing.

What is quite unlikeable is that he acts like a bully calling people names, insulting them, and so on.

He is allowed to do this because he is/was fast? Injured during sex? A moderator? Why ?

It seems ok to me to let him know.

I hope you will be equally concerned for me.

I just want to address one misconception that some may have. One cannot measure work and power from a force plate directly. All it can do is measure vertical force (if not a 2D plate) as a function of time. So one can measure the vertical impulse (integral of force vs. time) and hence the vertical momentum change during the impact. Information regarding the vertical displacement of the body vs. time is also needed to convert that to work and power. The only thing that must be true from a physics perspective is that the average force (including the time when F=0) must equal the weight of the runner. As such, the shorter the ratio of the impact time to float time (F=0), the higher the average force during impact.

I haven't scrutinized Lieberman's paper in great detail, but he seems to equate the force plate measurements with the shock to the body (maybe I'm wrong). To accurately determine how the body senses and responds to these forces that appear at the bottom of the shoe, he really needs to put accelerometers on the ankle, knee and hip. I suspect that he would find that the shoe completely washes out that initial spike and the foot would hardly sense a force spike at all.

wtf100+n wrote:Are you Malmo?

I have contributed some questions already. I like to read and listen more than posting to be right. Still, this is an interesting topic. Read the wtf posts in this thread. Some of my questions generated some answers which I am going to check on before i comment them ( what the lore of running says about heel striking - I dont have the book handy.)

I hope you will be equally concerned for me.

Nope, not Malmo, but if you have some questions related to the thread please go ahead and succinctly re-ask them rather than rambling on too much. I'm not going back to re-read this as I've spent far too much on this thread as it is!

Yes of course I am equally concerned for you...

Thank-you.

The combination of your manners and assertiveness will serve you well.

Having strong feet and optimizing footwork to suit one's running needs, seem entirely desirable objectives for athletes of all abilities alike.

to Lucky2B

actually you can measure displacement of the center of mass using a force platform. The force signal is proportional to acceleration (F=ma). The force signal can thus be integrated twice to get displacement.

This is quite commonly used by biomechanists to calculate the leg compression (delta L) and thus to calculate leg stiffness (F/delta L).

GA Cavagna first described the technique.

Force platforms as ergometers, J. Applied Physiology 1975.

The shoe does not wash out the shock transient that travels up the leg. Accelerometers do provide more information. They most definitely show shock travelling up the leg and the shock is greater in heelstrike running.

Whether that is good or bad remaims to be demonstrated.

Malmo is misunderstanding what distance change is relevant here.

It is not the distance moved forward, it is the leg length change.

wtf100+n wrote:Thank-you.

The combination of your manners and assertiveness will serve you well.

Having strong feet and optimizing footwork to suit one's running needs, seem entirely desirable objectives for athletes of all abilities alike.

You're very welcome good sir/madame.

Can you please explain what optimizing footwork to suit one's running needs means?

joe physics wrote:

to Lucky2B

actually you can measure displacement of the center of mass using a force platform. The force signal is proportional to acceleration (F=ma). The force signal can thus be integrated twice to get displacement.

This is quite commonly used by biomechanists to calculate the leg compression (delta L) and thus to calculate leg stiffness (F/delta L).

GA Cavagna first described the technique.

Force platforms as ergometers, J. Applied Physiology 1975.

The shoe does not wash out the shock transient that travels up the leg. Accelerometers do provide more information. They most definitely show shock travelling up the leg and the shock is greater in heelstrike running.

Whether that is good or bad remaims to be demonstrated.

Malmo is misunderstanding what distance change is relevant here.

It is not the distance moved forward, it is the leg length change.

True, but I think that it does still require that you make an assumption (which is probably reasonable) that the vertical velocity is zero when the compression force is maximum. Thanks.

I'm surprised by the statement the shoe does not absorb some of the initial impact shock; that is counterintuitive to me. The shoe has an elasticity, which must lead to some compression that would decouple somewhat the road from the leg. Reference?