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| John Richard |
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OK, let me try again, I reread the second part of 3)... 3) Lifting is NOT figurative, mental imagery. All you should do is lift. Yes, this is the conscious action described in POSE. There is no muscle contraction, voluntary or reflexive, that creates a horizontal force. Horizontal force comes from gravity moving the center of mass forward and down. POSE describes muscle elasticity being involved, I am fairly certain. Other than that, I do not know how Dr. R would explain this. To me, this is unclear aside from the "don't think about" mantra. In my mind, this is where POSE exits the conversation. It does not do a good job (and perhaps not intended to) describing what is actually happening. Anything I wrote past "I went back to the Charlie Francis..." is my own speculation and has nothing to do with what POSE actually is or teaches other than the point I try to make. |
| Jhuffman |
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Asterix, 1.) Yes, agreed! 2.) Yes, agreed! 3.) Pose believes that there is a point in the gait cycle where gravity is propulsive, redirecting from downward to forward. The point in the gait cycle where this is possible is from maximal vertical ground reaction force until toe off. At this point(at peak vertical ground reaction force), the CM begins to move over the support foot(ball of the foot). The body(CM) rotates forward and upward, while the foot acts as a pivotal point. Rotational movement of the body created by gravity appears as a gravitational torque, so that the body can fall forwards. 4.)Yes, agreed! |
| sfu'ed |
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If I may add a little, From my limited understanding of pose, I think the emphasis on pulling is meant to reduced push-off as much as possible. Our bodies involuntarily push when running to break our fall, but consciously thinking about only pulling can minimize excessive pushing. Also, I haven't fully analysed this part physically (I am a physicist afterall) but it feels like a reduction of pushing allows one to retain more energy by elastically "bouncing". There is probably an explanation in the shorter ground time leading to less energy wasted in geometric deformation ... but like I said, I haven't really analysed it. One other thing. A while ago, before I had looked into pose very much, I was thinking about the limiting factors to running speed. Basic physics states that when a force is applied on a mass, the mass should accelerate, until it reaches an equilibrium with frictional and other forces. Well, I was constantly applying a forward force while running ... yet I would very quickly reach a steady pace. At 15, 20, 25, or even 40km/h, the frictional forces with the ground and air resistance are no where near large enough that we should reach equilibrium; so why then, can we not accelerate continuously to speeds around 100km - 200km per hour. I could think of only one cause, that has 2 variables. For the time that ones foot is in contact with the ground, they (their center of mass) can only move forward a limited distance (determined by leg length and flexibility). As such, for that time, we have a set velocity. Velocity can not increase discontinuously (at least in the macroscopic scale ;)), hence, our overall running velocity is set by those two parameters ... ground time, and ground movement span. Of the two, the one that has the most room for improvement for most of us is ground time. |
| alfamalfa |
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| Jhuffman |
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Jim, Again, here is the answer: There is push off in running, but it happens by itself. Muscular elasticity does it for us and we actually use our voluntary muscular efforts just to hold the body position. That's it. |
| Gatorade |
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"You can avoid thinking about something, yet it still happens. That's entirely different than it not happening at all. Why am I being so persnickety about this? Because it makes a difference when you look at the physics of it, and that's where you can determine whether or not a claim is viable." It's not that simple, only theoretically everything can be reduced to physics. As a former kyokushin fighter I can give you an example: in kyokushin karate contest ( kumite)if both fighters earn the same amount of points during the fight, the winner is declared by temeshiwari - that is, breaking technique: the one who breaks a bigger number of boards with his fist takes the win. Now - if you are a big and strong man, you can easily break one board, or two, or even three, and with the number of boards increasng the chances of you breaking your hand also increase. Meanwhile you can see a karateka who, being twice smaller than you, can break twice more boards or even bricks, and never break his hand. You could say it's training - but if we reduce everything to physics, such training would be impossible, because you could argue that certain tissues can withstand only certain mechanical impact, etc. The difference between the abilites of a karateka and an ordinary guy is their mental focus and determination -that is, we make things happen by THINKING they will happen. The same with walking on hot coals, lying on broken glass, etc. Of course, there are certain physical limits, but we can never know what they are. You know why you are not able to break a brick with your fist? Because you are afraid, when you stop being afraid, you are able to do it(if someone can break 5 bricks, by sheer physics I see no reason why you can't break one). The same with falling forward in Pose: your mind is afraid to fall, and you reflectively try to get a hold onto something (that is, you reach with your foot in front). It takes a lot work and drills to overcome this, but believe me - when you get it, then you know what's it all about. I remember when I got the feeling of the "free speed" for the first time ( gravity pulling me forward and me only picking up my feet not to interrupt the continuos forward motion), I didn't want to go home for fear that I will lose the sensation and that I won't be able to reproduce it tomorrow. And believe me, when you get that feeling, you don't give a rat's ass about all the vectors and such. I don't see why someone should not try it just because he can't justify it intellectualy (well, maybe I'm wrong - one has to believe to make it possible for him). All the metaphysics aside - Huffman has answered it clearly: gravity pulls you forward, and stored energy of muscles and tendons helps to regain the lost height. All the vectors game is irrelevant. Just do the "Change of support" drill: stand in running pose ( on the balls of your feet, your support knee bent, head, shoulders, hip and ball aligned in one vertical line, the other foot under your hip), start leaning forward from the ankles ( don't bend at the waist), and when you lose balance and feel the urge to put the hanging foot on the ground - pull the support foot off the gound, and here you are - you are in running pose again, only a bit more in front of were you were. The question is: YOU HAVE MOVED FORWARD.WHERE IS THE PUSH-OFF? |
| Gatorade |
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" We'd previously reached agreement between ST, JimFiore, Alex S and myself that there MUST be a conscious push-off since the body is not a lossless system and simply can not return all the energy stored up on landing." Talking about physics reminds me of a story: a student preparing for the zoology exam learned only about earthworms. The professor asked him about elephants, and the student said: "The elephant has a trunk, and its form ressembles an earthworm. And earthworms live in the earth...". Then the professor asked him about rabbits, and the student said: " Rabbit has a short tail. If he had a long tail, it would look like an earthworm. Earthworms live in the earth..." What's the difference? If you push off, you work against gravity 100% ( like jumping up in basketball). If you follow Pose reccomendation to fall forward when running - well, let's say, ( just let's imagine) you are right saying that there still must be conscious push-off since stored energy is not enough to fully regain the lost height - if you harness gravity to propel you forward and leave ( let's say) 10% for push-off, means you become more eficient, and if you will reduce push-off to (let's say) 5% - you are still more efficient. And if you reduce it to 1%? Or 0.5%? I don't see how all those calculations relate to running practice. We can place the question like this: "Which is correct: 1. There is no conscious push-off. OR: 2. We try not to push-off consciously (meaning that there must be some conscious push-off that we are not aware of - but is it conscious then?)"? My answer would be: what is the difference? Well, there might be a difference for theoretics - but what difference does it make to one's running? You push-off and work against gravity. I don't push-off and let the gravity do the work ( I TRY to) - you would say that I only reduce my pushing off, well, let it be, and when I will reduce it from your 100% to my 10% ( or 5, or 1% - the numbers are just examples, so don't get a hold on them), I'll become a more efficient runner, because I will be letting the gravity do the work. You got it? I don't care if 1% of conscious push-off is left, I care that I managed to get rid of 99% of it, and that means that gravity is really doing the work - and it's not just a metaphor. |
| Gatorade |
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For convenience it may be put like this: the more the push-off is replaced by falling, the more efficient you are, and when your push-off approaches near-zero level, you are running Pose. I don't know if this concept of mine is in line with orthodox Pose explanation, but the main thing is that it works for me. |
| Gatorade |
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"We'd previously reached agreement between ST, JimFiore, Alex S and myself that there MUST be a conscious push-off since the body is not a lossless system and simply can not return all the energy stored up on landing." Let me make several more points: 1. "We reached agreement" - that is, the agreement was reached among people who didn't argue each other's point of view (except, maybe, ST). Such kind of an agreement should be considered a huge progress, LOL. 2. You should be aware that in many cases the whole is more than arithmetical sum of its components. Dissecting everything you can find yourself in the position of a scientist, who, after thoroughly investigating human brain under electronic microscope, had to admit that he didn't find neither reason, nor soul. Could we then make a conclusion that soul and reason are NOT the products of the human brain? 3.Do a drill: stand erect and then lean forward from the ankles until you lose balance. I'm sure you'll be able to do it. Pose instructs to lean from the ankles, not bend from the waist. With your intention to dissect everything you could argue that to be able to lean from the ankles one must give the body some kind of an impulse to start losing balance, some slight bending at the waist. This reasoning would lead to a false conclusion that it is IMPOSSIBLE to lean from the ankles, because some slight bending at the waist must initiate it. While practice shows that it is POSSIBLE to lean from the ankles, and that is quite different than bending at the waist. (The same with your "it's impossible for gravity to propel you forward"). Dissectihg everything one risks to find himself in the position of the proverbial centipade: the centipade was so focused on in what order to move his extremities that it stumbled and fell, despite of having 100 feet. |
| Asterix |
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Ok, we're getting somewhere!
Please allow me to ask the next series of questions so I can try and determine exactly what it is POSE believes/states on this tricky matter. Please correct any mistaken assumptions on my part. - Assumed: The CM reaches its highest point at the instant it moves over the support foot. After that, we're falling. - Once you've started falling, while it moves in the horizontal direction, is there any change in the vertical displacement of the CM? - Does POSE believe that any change in the vertical direction of the CM due to falling can be replaced purely by energy stored up in muscles and other elastic tissue purely from absorbing the fall itself on the next support? (ie that once falling has been started, no further conscious pushing is required to maintain continuous strides.) I'm sorry this appears labourious, but I'm trying to pin down exactly what POSE believes and this is our most contentious point. I hope both these questions can be answered with yes/no. |
| Alex S |
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Ok. There seems to be a concensus from POSE advocates on: 1) Any push off that occurs is not conscious. but i'm still a little unclear as to who agrees / disagrees with: 2) There must necessarily be a contribution to the push off from muscle contraction over and above the return of elastically stored energy. (Irrespective of whether it is unconscious, reflexive of whatever). Also, JHuffman and Gatorade do consider (wheras ST does not?) that: 3) At at least some point in the gait cycle, gravity provides forward propulsion. Sorry if this is getting repetitive, but i'm just trying to assist getting a clear summary of the POSE point of view on these points. |
| Asterix |
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It's tempting to get carried away into another point-by-point response, but in the interests of keeping things clear and concise, can I assume from your paragraph here that your answers to the two questions I posed to JHuffman at 5:50am just above are 'yes' and 'yes'? |
| Alex S |
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You give the number "3", but your comments describe 1 or 2 (depending on whether the 'other stuff [that] happens' is purely reflexive). |
| Alex S |
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"For the time that ones foot is in contact with the ground, they (their center of mass) can only move forward a limited distance (determined by leg length and flexibility). As such, for that time, we have a set velocity." I don't follow that - why can't the COM move forward that limited distance at a faster speed?? Let me add something, and it might make sense why that equilibrium is reached at speeds much slower than 100-200km/h! The force a muscle can generate decreases with increasing speed of contraction (speed of muscle shortening). Thus, as well as resistive forces increasing as we run faster, the propulsive forces we can generate also decrease. Example: You remember pushing a roundabout faster and faster when your mates were riding on it? Its easy to accelerate when its going slowly, but when it gets to a certain speed, its difficult to get any more 'push' on it. Same principle in effect. |
| JimFiore |
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But what does "it happens by itself" mean? Does "muscular elasticity" mean there's a muscle contraction? Is energy expended by the muscles or you implying that all energy simply comes from the release of stored energy (i.e., from the shock of the prior landing)? This is the problem that I'm having with the explanations: vague terminology.
No. We're talking about the fairly straightforward motion of a body. Physics (mechanics) applies perfectly well to this problem. To argue that one cannot apply physics to this problem is stating that the motion of a human being is outside the realm of basics mechanics. There is nothing about the masses and forces that would imply that. Now, you might argue about perceptions, but that's another ball of wax. In fact, the commentary regarding breaking bricks, walking on hot coals, etc. are NOT extra-physical: analyses have been performed on these and similar actions and they are explained perfectly well by physics. They are NOT outside the boundaries of it. While I understand that our perception of reality is at least partly based on belief, no amount of belief can counter the basic physics of a situation. The reason I don't try to smash bricks with my bare hand is not because I don't believe it's possible, but because I know it takes proper training to do so. Now, belief may be part of that training (perhaps self confidence is a better term), but it is by no means the only prerequisite to success. Conversely, no amount of belief will ever allow a person to stop an on-coming train with their fist. The physics of the situation will not allow it. As physical beings, humans are bound by physics. As far as not seing a soul or reason while looking at a brain through a microscope is concerned, all you've managed to describe is a researcher who is using an inappropriate tool for the job at hand. Just because I can't measure coronary problems with a bathroom scale doesn't mean that you don't have clogged arteries or a messed up valve, what it means is that I should put the scale aside in favor of an echo-cardiogram.
Vectors are not irrelevant unless you are also claiming that this is not a physical system. To be VERY precise, you say that stored energy "HELPS to regain the lost height". This implies that there is something else. What is that something else? Is it a muscle contraction? Is it gravity? What? |
| JimFiore |
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I don't nderstand why you'd say that I'd think one would have to bend at the waist in order to lean from the ankles. That's tortured logic. I could keep my body rigid and contract the frontal shin muscles (i.e., the action used to flex the foot upward). |
| bad connection |
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let me sum some things up about pose: -landing under center of gravity--recomended b4 pose by others -landing flat foot (or not on heel)-recomended b4 pose by others -Not moving ankle joint and leaving it along-recomended b4 pose by others -leaning from the ankles-recomended b4 pose by others so basically, the only thing "new" is their concept of gravity doing work. But we're not arguing concepts we're concerned with what is actually done on the run. So the only thing "new" seems to be a premature lifting of the foot off the ground. |
| JimFiore |
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I'd like a clarification in regards to Asterix's post of 5:50 with regards to the comment above. I'm not quite sure what you're refering to by "peak vertical ground reaction force" but I'll let that go for now. Instead, I'm more curious about the CM moving over the ball of the foot. You state that the body rotates forward and upward at this point. First, I was under the impression that the runner needs to land with the CM directly over the ball of the foot in pose, so it seems that he wouldn't move into this position while the foot was already on the ground (to do so implies that the foot landed ahead of the CM). Thus, at landing, the CM is as high as it ever will be while the runner is in contact with the ground. As the body pivots around the foot, the body would move forward and down, not forward and up, UNLESS some vertical force was added (such as contracting the calf muscles). Was that a typo, or does the body move forward and UP, and if so, how does it go UP if the body is simply pivoting around the foot and it's already at max extension and 90 degrees to the ground? |
| Posenaked |
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I don't want to interrupt all the physics scholars here, but I will anyway. Let's say I developed a training method that involved doing half of my workouts running backwards, and it was quite successful for me. I then make a website and tell some runner friends about it because I am simply trying to help them, as I know that I have developed a successful and revolutionary training plan. Some believe me, but most scoff at me, and tell me my plan is ridiculous. Why would I go to great lengths to try and convince those who dismiss me that I am right, that my training methods are brilliant and could help them? Wouldn't it make more sense to try once to help some people out, and if they don't want your help, well then, that sucks for them? This is what confuses me about pose. These people, ok maybe its just 2 or 3 of them, are vehemently denying any criticism of pose and doing all that they can to make it look good. Why don't they just say, hey you know what, pose works for me, it works for some friends/teammates of mine, and if you don't think it works, f*** off. |
| TRNR |
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After 24 pages, finally a brief, well written synopsis emerges. Thank you. |