The Enigmatic Benefits of Pose

My post ‘Natural Running’ posted on March 29 has so far elicited 157 comments, which at first sight might indicate that it was a topic of wide popular appeal.  While I hope there is some truth in that, the number of comments actually reflects something different.  Of the almost 4000 apparently ‘serious’ views of my blog ( not including the almost countless number of spam hits) in the past three weeks, only 288 were views of that page.  Meanwhile, in the same three week period, my post from early March, ‘Does Usain Bolt run Pose Style,’ has been viewed over 500 times, while two of my perennially popular pages (‘Why do Marathon Runners have Skinny Legs?’ and  ‘HRV during Exercise’) have drawn a few hundred views each, as is typical of any three week period.   The popularity of the Bolt post is a pointer to the explanation for the large number of comments on the ‘Natural Running’ post. The majority of the 157 comments have been discussions between Jeremy, Hans, Simon and myself on issues closely related to Pose style.

I have enjoyed participating is this lengthy discussion especially because it has yet again emphasized several of the characteristic features of Pose.  One is the issue that drew Hans in to the discussion.  As I remarked in a recent post, Hans is a runner who previously suffered a number of injuries while running with an approach based on effortful pushing.  However, apart from some transient Achilles tendon problems, has enjoyed a relaxed, injury free running since taking up Pose, under the guidance of Jeremy.  Hans has been eager to understand the physics and biomechanics of running but has been left with a dilemma: how can he explain the clear success of his current relaxed Pose style of running in light of the apparent conflict with the principles of physics and biomechanics.  He has continued to design experiments to demonstrate that gravitational torque might provide kinetic energy which can be harnessed for propulsion when running.   We have discussed his proposed experiments in some detail in the comments section of ‘Natural Running’.  Hans has a clear enough understanding to see that ground reaction forces, both horizontal and vertical, must account for forward and upward motion of the body, but is still trying to devise the experiment that will demonstrate the role of gravitational torque, for the understandable reason that his experience demonstrates that Pose works.

Simon has occasionally chipped to the discussion between Hans and myself, sometimes to re-inforce to Hans the inevitable consequences of Newton’s laws of motion, and sometimes to remind me that even though Newton’s laws clearly demonstrate that a push against the ground is required, this is a push that is largely automatic, and to warn me that my use of the term ‘push’ creates danger of misdirecting recreational runners towards a running style that emphasizes conscious push against the ground.  In fact I agree strongly with Simon that for many runners it is counterproductive and perhaps even dangerous to produce a conscious push.  Meanwhile Jeremy, who was an elite athlete with a sub-4 minute mile to his credit in the days before he took up Pose, has contributed comments reflecting the more typical position of a Pose advocate: namely that experience demonstrates Pose is unarguably the right way to run and anyone who questions this is simply wrong.

As I have pointed out several times in the past, I have been  fascinated by Pose for almost eight years on account of the fact that  many recreational runners have found it has helped them run with fewer injuries, at least once that they have got beyond the Achilles problems that are common in the early stages.  As I and others have frequently pointed out, Pose is based on a faulty understanding of physics and biomechanics, so what is the secret to its success?

The most immediately apparent answer is that by creating an illusion that gravity provides free energy, Pose encourages the runner to stop consciously pushing against the ground.  Since we are far more likely to push as the wrong time or in the wrong direction if we try to impose conscious control on the organization of a process that is better left to the non-conscious motor control system in our brain, it is not surprising that Pose often works well, at least for recreational athletes.  However, if decreasing the rate of injury is merely a matter of disengaging our conscious mind from involvement in the task, simply chatting with a running partner should work just as well.  This is probably not the case, suggesting that there are some more positive reasons why Pose works.

While it would be fatuous for an outsider to claim to understand Pose with the insight of a disciple fully imbued with the tradition and rituals of the practice,  the long and challenging discussions with Hans and Jeremy left me with a feeling that I now understand what it is about Pose that works sufficiently well to allow me to fit these beneficial features into my own approach to running, without the need to embrace the cartoon physics.   So what are the elements of Pose that might be beneficial?

 

Acceleration

First, it is important to note the role of gravity is accelerating, either at the start of a run or when changing speed.  Leaning does allow us to use gravity to generate kinetic energy which can then be re-directed to provide horizontal acceleration by means of ground reaction force.  This involves a push against the ground but this push is mainly a reflex action to stop falling on one’s face.  So there is no doubt that gravity helps acceleration, even though the work is ultimately done by the muscles.  For a sprinter, he/she consciously pushes against the starting blocks and the ground but an endurance runner rarely perceives the push.

 

Minimising time on stance

When running at a steady speed, Newton’s first law, which states that a body continues in a state of uniform motion unless acted upon by a force, tells us that we can minimise the need for any push by minimising braking.  We minimise braking by spending a small time on stance.  There are two feature of Pose that minimise braking.  The first is high cadence.  This results in a shorter gait cycle, including shorter time on stance and shorter airborne time. The shorter airborne helps reduce stance time by virtue of the fact that the impulse required to get airborne can be delivered within a shorter stance time (for a specified value of average vertical Ground Reaction Force).

The other relevant feature of Pose that helps achieve a short time on stance is the mental focus on rapidly pulling the foot from the ground.  This pull is supposedly led by a hamstring contraction (see Pose tech article 000280). In fact it is an illusion that pulling gets us airborne. It is a push that gets us airborne, though a substantial portion of the energy for this push is provided via elastic recoil.  By encouraging a mental focus on pulling the foot from the ground, Pose encourages a short time on stance. I believe this is largely achieved by producing non-conscious pre-tensioning of the hip extensors (hamstrings and gluteus maximus) in late swing, leading to a strong contraction of these muscles at foot-fall, thereby capturing impact energy as elastic energy and contributing to the build up of a strong push against the ground.  This arrests the falling body and propels it forward and upwards after mid-stance.  However, Dr Romanov argues that the hamstring contraction at the end of stance provides an upwards pull that breaks contact between foot and ground.  While there is no doubt that the push (admittedly largely automatic and powered at least in part by elastic recoil) is what generates the ground reaction force that propels the body upwards, it is nonetheless feasible that by pulling the foot towards the upwardly moving hips, a hamstring contraction might contribute to breaking contact.  To understand the role of this hamstring contraction, it is necessary to consider what happens in early swing phase

 

The mechanism of the swing

The principle role of the swing is to get the foot forwards from a position behind the torso at the end of stance to a position a short distance in front of the torso at footfall.  In early swing phase, both hip and knee flex.  The flexion of the hip causes the thigh to move forward and up while and the knee flexion causes the foot to swing upwards relative to the thigh.   In Post Tech article 000280 Dr Romanov acknowledges that both the hamstrings and hip flexors play a role in this, but he strongly emphasises that the hamstrings play the leading role.  He argues that it is preferable to focus on a hamstring contraction rather than a powerful contraction of the hip flexors because not much work is required to achieve the swing.  In Chapter 8 of Pose Method of Triathlon Techniques, he states: ‘There is no need at all to move the swing leg forcefully forward; all the runner needs to do at this point is to continue to fall forward’

His justification for this claim is based on a seriously mistaken understanding of Coriolis force, but his claim does indeed contain a germ of truth.  Coriolis force is a virtual force that is invoked to account for the path of an object viewed by an observer in a rotating frame of reference.  Neither the runner nor a stationary observer is in a rotating frame of reference.  Coriolis force might only need to be invoked to account for the trajectory of a part of the body viewed via a video camera mounted on a rotating part of the leg or arm.   And even for such an observer, the Coriolis force would not be a real force; it would simply provide a way of describing the fact that the observed body part is moving relative to the observation platform.  By invoking Coriolis force as the force involved in the swing while pointing out that it is not a real force, Dr Romanov creates an illusion that very little work is required to swing the leg.  This is simply wrong.  In fact, at high speeds, the energy cost of swinging the leg  exceeds the costs of overcoming braking and of getting airborne (as discussed in my post of  April 5th, on cadence).

However, the germ of truth comes in the fact that in Chapter 8 of Pose Method of Triathlon Techniques, Dr Romanov explains how Coriolis force works by referring to the equation for the moment of inertia of a rotating body.  In the context of the swinging leg, this equation for moment of inertia has nothing to do with Coriolis force, but is very relevant to making the swing efficient.  The change in moment of inertia accounts for the remarkable effect obtained when the distribution of mass in a rotating objects is adjusted to make the rotating body more compact.  The effect is illustrated most dramatically by a pirouetting ice skater.  As the skater draws his or her arms in towards the torso the speed of rotation in increases. This is because for the amount of force that is required to produce rotational motion depends on both the mass of the object and the square of the distance of each part of the body from the axis about which it is rotating.   The moment of inertia of a body about a given axis is the sum of a contribution from each body part calculated by multiplying mass of the body part by square of distance of that part from the axis.   A smaller force is required to accelerate a compact rotating body on account of its relatively small moment of inertia.  If the body is already rotating, the law of conservation of angular momentum ensures that making it more compact will cause it to spin faster without requiring  input of more energy.

With regard to the swing leg, if the foot is folded up near to the buttocks as a result of knee flexion, it has a smaller moment of inertia and requires a smaller force (and less energy) to swing it.  Most coaches simply refer to this as the benefit of a short lever arm.

By spuriously invoking the concept of the virtual Coriolis force, Dr Romanov  has emphasised that it is best to avoid consciously driving the swing.  In fact, the pendular swing of the thigh around the hip and the lower leg around the knee does require exertion of force.  It is not purely driven by gravity. However much of the work of swinging the thigh is done by the psoas muscle which is buried deep in the pelvis.  Because it plays a major role in maintaining posture and in many everyday actions such a climbing stairs, psoas is a fairly strong muscle in most people.  Many runners are not aware of it, unless it is injured; and then they sometimes find themselves incapacitated for a period of months.  However most of the time psoas gets on with what we require of it without need for conscious attention.

Furthermore in late stance, the hip flexors, including psoas, are preloaded by the stretch that occurs as the torso moves ahead of the thigh, thereby extending the hip.  So at the beginning of the swing, psoas and the other hip flexors contract automatically.  If they did not, the leg and foot would drag behind the torso.   Although Dr Romanovs’ emphasis on the hamstrings as the prime mover in initiating the swing is based on erroneous physics and biomechanics, in practise it is probably best to avoid consciously driving the hip flexors.  Conscious driving is likely to lead to over-striding, in which the foot lands too far in front of the torso producing excessive braking, which wastes energy and might increase the risk of injury

 

Conclusions

Thus despite being based on erroneous physics and erroneous biomechanics, Pose does encourage the runner to engage muscles that achieve efficient running in an apparently less effortful manner, and to avoid conscious forceful contraction of muscles which are best left to contract automatically.  If we are to run well we need to avoid unnecessary or mistimed pushing.  In particular we need to avoid wasting kinetic energy by unnecessary braking and we need to learn how to capture impact energy via elastic recoil.    I therefore think that for recreational endurance runners Pose is better than a running style that is based on the mistaken belief that strong conscious pushing is required.   Elite sprinters do need to push consciously, but that is not our present topic.

However, while Pose has advantages for the recreational runner, there are two types of problem with Pose.  First, it creates the illusion that large forces are not required and this illusion does predispose to some injuries.  Secondly, for a recreational runner who wishes to achieve his/her best possible performance, there is a risk of failing do the type of training that is required.  To give one very specific example, the Change of Stance and High Knees drills involve similar movements: the flexion of hip and knee of one leg as it rises while the other leg descends to the ground.  However, CoS promotes precise timing while High Knees develops powerful hip flexors.  Pose places a disproportional emphasis on CoS at the expense of High Knees.   If we wish to achieve our peak performance we need to ensure that the hip flexors, including psoas, are powerful.

Summary

The emphasis on minimizing push against the ground avoids the dangers of a mistimed or delayed push.  In practice a push is essential to get airborne and to compensate for braking.  Nonetheless, by promoting high cadence and rapid lift-off from stance, Pose minimises the amount of braking while encouraging a non-conscious push.  Similarly, by minimising the role of the hip flexors during swing, Pose reduces the risk of harmful over-striding.  In practice, the required hip flexor contraction occurs automatically.  For the recreational runner for whom avoidance of injury is more important that achieving peak performance, Pose has several features to recommend it, including minimizing the risk of protracted push against the ground and the risk of over-striding.

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21 Responses to “The Enigmatic Benefits of Pose”

  1. Ewen Says:

    Canute, there was an interesting blog post from Steve Magness about ‘Active’ v ‘Passive’ conditions in running form:
    http://www.scienceofrunning.com/2011/04/most-important-information-you-will.html
    He mentions that some movements are reflexive (for instance the trail foot coming up towards the buttocks), which we see when looking at “good” running form yet if we actively try to replicate that movement we are wasting energy.
    The fad of “gurus” and barefoot running is also mentioned in that there’s a market for runners wishing to learn barefoot running and good running form.

    • canute1 Says:

      Ewen

      Thanks for that link to Steve Magness’ discussion of passive v active movements. I agree strongly with the Steve’s overall message.

      I disagree about a few of the details. His statement that the flexion of the knee that brings to foot towards the butt is ‘simply an inertial force’. Is an oversimplification (as he would probably agree). Because gastrocnemius crosses both ankle and knee joints, after lift-off, the continuing elastic recoil of the Achilles probably contributes to the flexion. This is automatic but is not ‘simply inertial’. More interesting with regard to Pose theory is the question of whether hamstring contraction plays any role in this knee flexion. Dr Romanov strongly emphasises that the hamstrings are the leading muscles. As explained above, Dr Romanov is clearly wrong to describe the hams as the leading muscles, but his account may be partly correct. However, these issues about the mechanism of knee flexion are not very important The main thing is letting the knee flex automatically.

      There are two more important areas where I would challenge Steve. First, he emphasises not trying to cut stance time short. His rationale is that the extension of the hip that occurs in late stance helps to make the subsequent hip flexion more powerful. I agree with his rationale, but I am not sure that Steve gives full weight to the fact that having the foot on the ground too long after mid-stance is inevitably associated with greater braking before mid-stance. I am inclined to give a little more credit to the Pose emphasis on getting off stance quickly. It is time that I addressed the fact that time from mid-stance to lift –off is longer than time from foot strike to mid-stance. I have deliberately glossed over this fact in most of my writing so far, because it is related to wind resistance, but it is not accounted for fully by wind resistance. I plan to do a post on that question within the next few weeks.

      The other issue where I differ from Steve in the importance I attach to drills – I think that they can help improve form in addition to increasing strength and power. But mostly, I agree with Steve. I examine the evidence and think fairly carefully before I dare to disagree with him. He is not only well trained in biomechanics, but he has a lot of coaching experience and he talks to some of the best coaches in the world.

  2. jhuff Says:

    Canute,

    “””” Meanwhile Jeremy, who was an elite athlete with a sub-4 minute mile to his credit in the days before he took up Pose, has contributed comments reflecting the more typical position of a Pose advocate: namely that experience demonstrates Pose is unarguably the right way to run and anyone who questions this is simply wrong.”””””

    LOL…..I feel oligated to had a voice of reason to that of the ageing know it all physics professor that lacks real world experience of running fast 🙂

    • jhuff Says:

      ***obligated to add****

    • canute1 Says:

      Jeremy

      You have the almost unique experience of having run at world-class level using a ‘power model’ and subsequently changing to Pose style. I would be very interested to know what you have found to be the benefits of Pose.

      I should also add that over the years I have made a genuine attempt to establish what it is that makes Pose helpful to many runners. I have spoken to many Pose coaches and have attended one of Dr Romanov’s clinics, in addition to extensive reading and watching of videos. Although I remain sceptical of the underlying theory, I have nonetheless learned quite a lot that has added to my understanding of running mechanics. Therefore, I value your opinion just as I value the honest opinions of other Pose coaches, but I would appreciate a bit more explanation of the reasons for your opinions.

    • canute1 Says:

      Jeremy

      Thanks. I accept that it might not be easy to verbalise what the advantages are. Many of the features of fine motor controls are carried out in a way that cannot easily be expressed in words. That is why a fine motor skill is best learned by practice.

      For example, when doing a skilled task we sometimes get the almost indescribable sense that is called ‘being in the zone’. This is a mental state in which we become immersed in what we are doing in way that allows us to execute the task precisely and confidently without effortful control. I think perhaps this occurs when we become conscious of the function of our brain’s motor control system (which usually works best non-consciously) without the conscious brain trying to dictate exactly what the non-conscious control system should be doing. I have sometimes wondered whether the ‘secret’ of Pose is that the mental images it creates help achieve this experience of being ‘in the zone’. I would be interested in your opinion of this.

  3. Mike S Says:

    Still popping in every so often when time permits…

    A very insightful article Canute – particularly in pointing up some of Romanov’s misconceptions of physics when trying to explain Pose.

    In the wake of injury problems I had about 7 years ago, I got very interested in Pose, but in the end, wasn’t “converted”. I use the word advisedly, as I was left with the impression that a significant number of Pose practitioners embraced it like a religion.
    Reading your comment above, it occurs to me that maybe having that sort of mindset – blind belief in the method irrespective of whether or not it is objectively justified, unquestioning and refusing to “overanalyse” (or analyse at all) – makes it easier to get into “the zone”?

    Btw I did have to laugh at your description of Mr Huffman, which was all too easy to interpret as “a sub 4 minute miler – until he discovered Pose” 😉

    • canute1 Says:

      Mike

      Thank for your comment. I agree that it is likely the quasi-religious belief of Pose practitioners that the technique is the best, does discourage conscious analysis and this may create the sense of lack of effort that is a crucial part of ‘being in the Zone’.

  4. Jeremy Says:

    MikeS,

    Hi, I don’t think Canute intended his comment to be read that way. However since you are curious I did stop training to run 4min mile soon after discovering Pose. Personally I do wish I had discovered it earlier as I feel it has indeed made me a more efficient runner at all the speeds I desire to run these days. Though I don’t run track races very ofter any more I do still run and do some interval training. Infact just last week I completed 24 x 200m@30-32sec with 60sec rest between reps and 4min walk break after 8reps. In my books that isn’t to slow and it comes out to around 4:00-4:08 minute mile pace 🙂

    • canute1 Says:

      Jeremy,

      Mike expressed his comment as a joke so I do not think that it should be taken too seriously.

      However, perhaps underlying the joke is the interesting question of what you have found to be beneficial about the change to Pose, and I hope that at some stage you will provide a bit more detail on this.

      With regard to your current running, it is clear that you are still fast. This no doubt in part reflects you natural talent, and your current aerobic capacity, but also demonstrates that your current style is fairly efficient. I think that the practice of Pose (though not the theory) is potentially OK for a middle-distance runner provided he/she devotes adequate attention to maintaining leg strength and power (and of course aerobic fitness).

      The Pose emphasis on a rapid pull can actually result in the automatic delivery of a strong push provided the person has adequate leg muscle power. I note that you do a substantial amount of both plyometrics and also resistance sessions. Hence I think it is likely that you generate an adequate push automatically. As I recently remarked to Hans in response to one of his comments on my Natural Running post, I think Pose can be an effective technique even for a runner who wants to achieve a high level of performance, provided they devote adequate attention to the development of leg strength and power. You clearly do this. The combination of strength and power derived from plyometrics and resistance workouts with the precise timing that Pose encourages, is potentially a good combination

      One minor aspect of your style that I definitely disagree with is your use of a cadence of 198 steps /min even at very low speeds. However as you have no intention of taking up ultra-marathons, this is a matter of no consequence.

  5. Mike S Says:

    Hi Jeremy,
    Yes it was (mainly) a joke. But your comment “Personally I do wish I had discovered it earlier as I feel it has indeed made me a more efficient runner at all the speeds ** I desire to run these days. **” (my emphasis) is interestingly nuanced.
    To me that reads suspiciously like an admission that Pose isn’t the most efficient at ALL speeds.
    Romanov never did attract a truly elite-standard athlete into embracing Pose did he? Even though it was fairly clear he wanted to recruit such a person.

    • Jeremy Says:

      Mikes,

      Clearly you like to change the meaning of things that you read, however my statement meant what it stated. I believe knowing and using the pose method would have given me a platform to achieve my best and I wish that I had known of it has a child. I am grateful to have discovered it when I did back in 2005. I now sustain both high speed running and slow speed running with great efficiency and joy.

      • Jeremy Says:

        Mikes,

        I haven’t spoken to Dr. Romanov in a number of yrs so I don’t know who exactly he is training. Perhaps you should ask him.

  6. Mike S Says:

    Jeremy,
    In response to your first reply:
    I changed nothing, simply drew the most obvious inference from six words you volunteered.
    So, you’re a master of the Pose Method of Backpedalling as well? 😉

    In response to your second:
    Don’t need to – we’d all have heard about it if he’d recruited a top-class athlete.

    • Jeremy Says:

      Mikes,

      Let me help you out with the meaning of those six words. It was a much shorter way of describing my current running vs giving all of the details of how much and how fast I run on a day to day basis currently. Since simplicity confuses you I will give you a few more details. I do about 20-35 miles a week. Mainly general conditioning and to be competive enough to place top 3 in local 5km races. I also generally run 1-2 interval sessions as well for fun and fitness. My mental focus now is enjoyment of running rather than pushing my body to maximum performance limits for racing. Unfortunately I do not live in an area with a local track circuit or I would definitely get out and enjoy doing the 200m-1mi races as those are really fun to me. I am hopefully that that clears things up for you but I will check back to see if you need further clarification 😉

      • canute1 Says:

        Jeremy,

        I find it easy to believe that Pose suits your present running goals well. In particular it does not surprise me that that Pose together with plyometrics and resistance work allows you to enjoy relaxed running while still running reasonably fast. The majority of recreational runners would be happy with 30-32 sec for 200m repeats. However the question that interests me is what made you decide to move from the ‘power’ running style with which you had achieved a sub-4 minute mile in 2002, to Pose . I note from your posts on Letsrun in 2004 that you were already experimenting with doing all your training in racing flats in the same year as the Olympic trials. This leads me to ask whether or not you were already moving towards a Pose-like style several years before you officially adopted Pose style, and if so, why?

      • Jeremy Says:

        Canute,

        The answer has already been provided a few times I believe, however as I get sometime I will try to clarify things for you.

    • canute1 Says:

      Jeremy
      Sorry that I have not managed to discern the answer to this question in your previous responses. I would be grateful if you could provide the answer again.

      I am asking because I genuinely wish to understand. Just because I believe Pose theory is wrong does not mean that I believe it does not work in practice. I believe that the functions of the human body (and mind) obey scientific principles, but I also believe that many of the mankind’s skills were developed on the basis of intuition rather than academic science. Hence I believe that understanding the intuitions that led to Pose is potentially helpful in understanding why Pose works for some people. I think I have learned quite a lot by talking to runners who have found Pose helpful. You are a special case because you are one of the few runners who achieved elite status and subsequently found Pose to be helpful. Therefore I do value your opinions even though I might disagree with some of your conclusions.

      • Jeremy Says:

        Canute,

        My switch to from a more or less “power running style” to a Pose Method running style had to do with my experience of running fast and my internal knowledge of the concept of human movement. As for training for running 4min mile training that stopped in late 2006 because I felt it was time to focus my energy and efforts on family rather than being consumed by being the fastest runner I could be at track races. Don’t get me wrong it was a tough decision. I enjoyed competing at a high level for 14yrs, but I felt it was time to shift my focus to family. Technique is something I only began exploring inorder to work with other runners in helping them improve their running and injury issues. Throughout my exploration into the differing ideas I came across Pose and in short it most closesly resonated with my experience of running. Along with of course the theory and application make the most sense to me for training for technique. It was actually a side benefit that I realized that my own technique could be improved upon. Of course there are some more detail I could give if I had more time but that is a pretty good summary. let me know if you require more and when I get time I will fill in the blanks.

      • canute1 Says:

        Jeremy
        Thanks for that explanation. I can easily understand your decision to sacrifice training for top level competition so that you could focus more on your young family in 2006, and can also appreciate that it was not an easy decision to make. It also makes sense that in your role as coach of college athletes you directed your attention to technique, especially to ways of minimising injury. At least with regard to the important issue of knee injury, there was a rational reason to explore the benefits of Pose, and it reasonable to expect that Pose would reduce at least some other injuries related to mis-application of excessive force.

        As I understand it you were already using racing flats for all of your training by the end of 2004. I would be grateful for a little more detail on why you made that change.

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