Archive for April, 2012

Wilson Kipsang and Memories of Running in the Zone

April 26, 2012

My recent posts have dealt with two linked themes.  On the one hand I have speculated about ‘natural running’ characterised by harmonisation of a kinesthetic sense of where one’s limbs are in space, with well-practised movements dictated by the laws of physics and biomechanics.   On the other hand I have returned to my recurrent theme of the apparent conflict between the fact that running requires the generation of large forces yet conscious effort is often counter-productive.  The muscular actions that are required for getting airborne and repositioning the swing leg are largely automatic, and best left to the non-conscious control system in our brain.  Attempts to impose conscious control create a risk of mistimed or excessive force that is not only inefficient but also risks injury.  If we are to perform at peak level, the challenge is to achieve a conscious overview of the non-conscious control system that harmonises our rational planning with automatic action.

There is indeed a well known mental state in which this is possible – the elusive mental state popularly known as the Zone.  It is a state with four principal characteristics: complete focus; harmony within oneself; total confidence and the experience that performance is virtually effortless. It is the state most clearly seen in top-level tennis. It is the state that allows a player to spring sideways with racquet outstretched to make a cross court shot that skims a few centimetres above the net and raises a cloud of chalk dust from the line in the far corner of the court.  There is no way that such precision of motor control could be achieved by conscious control.  When a player in is in this frame of mind he simply knows he going to win.

Running in the Zone

Running in the Zone is less dramatic but the feeling can be as powerful.  I was reminded of this by Wilson Kipsang’s seemingly effortless victory in the London marathon a few days ago.  Though actually it was his performance in Frankfurt last October that evoked more powerful memories for me.  I watched this video clip of the final two Km of that run in which he came within a few seconds of the world record, set only a few months earlier in Berlin by his countryman, Patrick Makau.  Watching Kipsang’s lithe and powerful legs while I listened to the German commentator brought back a personal memory of an event over forty years previously.   The magic was enhanced by my limited understanding of German: good enough only to allow me to appreciate that the excited yet controlled voice was reeling off the passing kilometres, and the minutes and seconds that indicated Kipsang’s progress towards Makau’s world record time of 2:03:38.  But my lack of full appreciation of the commentator’s words heightened my awareness of the power and elegance of Kipsang’s gait. To my eyes, he was the archetypical illustration of a runner in the Zone.  As in London, where he missed the count-down for the London course record by a few seconds, in Frankfurt, he missed the world record by a similar amount despite the shower of tickertape and flashing lights as he crossed the finish line.

Small town glory

For me, it evoked a memory of much humbler surroundings.  As I have mentioned before, in my younger days I could reasonably have been described as a sub-elite marathon runner, but as a track athlete I was an ‘also-ran’ with limited talent, prepared to run any event, from 400m hurdles to 3000m steeplechase or 5000m, as required to earn points for my club.

I won less than a dozen races in my entire track career.  The most memorable was a mid-week evening 10,000m on the old Adelaide Harriers cinders track.  As described in a previous post, it was a low key meeting but offered one of the few track 10,000 races in the local athletic calendar. I arrived straight from work only just in time to line up at the start, without even time for a warm-up.  From the gun I was running confidently and harmoniously.   Within a few laps I was calmly confident that I would win – though in fact I had never previously run a 10,000m on the track and had no realistic knowledge of what lay ahead of me.  I was simply running effortlessly with all-embracing focus, complete harmony within myself and with calm confidence.  As the laps slipped by, I continued to run harmoniously and virtually effortlessly. Even the sprint over the final 300m felt more like a celebration than a challenge. I have no record of my time.  It remains my lifetime best as I have never had the opportunity to race 10,000m on the track since, but the memory of the race matters more than a record of the time.

The following Saturday, I lined-up for the 5000m in the local interclub series.  The field included most of the top 5000m runners in South Australia at that time, but that mattered little to me. My goal was to win points for my D grade club and for this my placing among the A grade competitors mattered little.  Nonetheless, some of the aura of the previous Wednesday night still cling to me, and as the leaders jockeyed for position in the home straight with a little over one lap to go, I was in fifth place, on the shoulder of the current state 5000m champion.  Although the pace was a little faster than the 10,000m pace a few days earlier, again I was running harmoniously and almost effortlessly.  Up to that point the thought of winning had not even occurred to me, but suddenly it seemed possible.  With a little over 400 metres to go, I surged to the front.  The sound of the bell and the sight of the open track curving away to my left as I entered the final lap remains as clear in my memory as the event at the Adelaide Harriers track the preceding Wednesday evening.  I was oblivious of the runners behind me as I rounded the bend and sprinted along the back straight.  It was a wonderful feeling, but of course it was too good to last.  With 180m to go the state champion slipped by, and in the home straight I faded to finish in sixth place.  I did of course secure maximum points in the D grade competition, so sixth place was more than was required of me.

In the minds of the leading runners jockeying for position as we approached the final bell, I would have scarcely warranted a second thought.  So I was delighted when the state champion came up to me afterwards and said:  ‘You started your run too soon but I couldn’t just let you go. You looked too dangerous.’  To know that I had even appeared to be a threat is a pleasing memory, but even more satisfying is the mental picture I still retain of sound of the tinkling bell and the sight of the clear track ahead as I led into the last lap.  Perhaps if Ihad held off my sprint for another 100m I might have finished even nearer the front but I have no regrets for having seized the moment when I did.

These memories are largely nostalgia for times long ago, but I did enjoy a minor reprise of the feeling of being in the Zone on my way to victory in the second division of East Midlands Fetch Challenge mile three years ago.  Nowadays, I step onto a track only occasionally.  However I do still cherish the experience of running in the Zone.

The elusiveness of the Zone

One of the paradoxes of the Zone is that if you focus too much on being in it, you cease to be a detached observer of your own mental and physical state, and the Zone dissolves.  It is an elusive mental state that cannot be grasped too tightly.  Being in the Zone is not in itself the primary goal.  However provided you can allow your conscious mind to trust the non-conscious control system in your brain to look after the fine details, it is possible to do things beyond the capacity of your conscious mind.  I believe that my few fleeting moment of ‘small-town glory’ on the track many years ago were a product of this state  Of course no mental tricks can make up for lack of strength and aerobic fitness.  But if you want to run at the limit of your physical capacity, I think it is a crucial element.

If one examines carefully the various descriptions of his mental state provided by Usain Bolt, the theme that emerges most strongly is mental focus. Here is his response to Desmond Howard’s question: How about during the race? What do you see? What do you hear?’, in an interview for ESPN.  ‘The first 40 or 50 meters, I’m aware of almost everything because that’s the weakest part of my race, so I always check immediately if I got a good start. Maybe after 20 meters, I check again — trying to tell myself to keep my technique right. I look around a little bit, but I don’t really hear the crowd much over 100 meters because I’m so focused.’  His mental state during the acceleration phase is dominated by intense focus but his description does not convey the sense of effortless harmony and self confidence that characterises the Zone.  A man of his physique has to work hard to get his long legs and large frame up to speed.  Video recordings show his torso rocking from side to side as he strains to push against the ground.  His own account confirms this picture.  But once he is at top speed his stride length is an advantage, and everything fits into place.  Watching the cruising phase in video recordings of the 100m final in Beijing, the World Championship in Berlin in 2009 or many other races during his period of world domination everything about his demeanour conveys a sense of effortless, harmonious self-confidence.  He is a picture of a runner in the Zone.

It is noteworthy that Bolt is aware of the weakness of his acceleration phase.  It is a weakness that arises from the physique that serves him well later in the race. In part, he is the world’s fastest sprinter because he is has the capacity to perceive his own weaknesses.  Being in the Zone does not replace the need for strength, skill or, in the case of endurance running, the need for aerobic fitness.  It reinforces these things and is reinforced by them.  It is a mental state that allows us to exceed the capability of our conscious mind.  If Bolt can achieve harmonious mastery of his own huge frame in that first 40 metres, he might release the latent skill that will take another 0.03 seconds off his time.

I believe that a factor of key importance for any runner who aims to run as well as they possibly can is the ability to create the circumstances that open the door to the Zone.  Developing this capacity is as important as building aerobic capacity, strength and skill.  As a result, the goals of each training session includes not only enhancement of some aspect of aerobic capacity, strength and/or skill but also specific attention to cultivating the ‘present-centredness’ that is the foundation of the Zone.

Zone-oriented training

Because of the Zone defies capture, the goal of Zone-oriented training is not to achieve the Zone, but simply to create the circumstances that allow it to happen.  My own experience suggests there are five key elements.

  • The first is body awareness.  The goal is subliminal awareness of every  part of the body, but I find it most helpful to focus mainly in my thumb and forefinger as each arm swings down to my waist, in turn.  The action is not forceful but it is firm and precise.
  • The second element is relaxation of muscle tension.  The light pressure of thumb against forefinger allows my non-conscious brain to calibrate the tension in my arm and the opposite leg optimally, while I also direct attention to relaxing my shoulders.
  • The third element is harmonising my breathing with the rhythmic movement of arms and legs.  Not only does the depth of breathing and ratio of breaths to strides provide me with a sensitive measure of where my effort level is in relation to my anaerobic threshold, but the awareness of the rhythm acts to stabilise this rhythm and enhance the sense of calm detached conscious observation of my non-conscious motor control system in action.
  • Fourthly, I aim for a feeling of lightness.  Largely this is based on conscious awareness of the impact of my feet on the ground.  I am subliminally aware of, and from time to time overtly attentive to, the way in which the load is distributed over the arch of my foot during stance, as I observe the light sound of my footfall.
  • Finally I cultivate an awareness of the rapid forward swing of the leg from stance.  This is entails a mental image of a graceful arching trajectory rather than a deliberate contraction of any particular muscle group, though my understanding of biomechanics suggest that iliopsoas does most of the work, facilitated by recoil of the Achilles tendon at lift-off, and a light contraction of the hamstrings.

 More recent memories

My ability to sustain present-centredness was tested in an interesting way a week ago.  The riverside paths on which I run are fairly popular with people walking their dogs.  Most days I encounter at least a dozen or more dogs, and over the course of each month I can expect to meet several hundred animals of varying breed and temperament.  In the open spaces along the riverside, most dog-walkers release their charges from the lead, so it is not surprising that from time to time I am chased by some poorly trained animal.  Usually I stop and point to the ground while saying in a firm voice: ‘Stay!’  In most instances this is at least moderately effective, except with little yappy dogs, whom it is best to simply ignore.  However last week as I ran along the banks of the Trent with a pleasing feeling of relaxed harmony, I found myself the quarry of a Great Dane.  Great Danes have a lineage that extends back to their original breeding from wolves for use in wolf-hunting, but generations of domestication have made them reasonably docile and they rarely exhibit a strong prey drive.  However this fellow appeared to have identified me as prey.  As he would have stood at least 7 feet tall on his hind legs, I doubted that I would sounded very authoritative if I stood my ground and commanded ‘Stay’.

The memory of a similar experience  as I ran along the banks of the River Soar a few miles from it confluence with the Trent a year ago, flashed into my mind.  Shortly after passing an unfriendly-looking Alsatian prowling along the bank, I was aware of a flurry of movement behind me and the beast leapt to grasp my wrist in his jaws.  The power in those jaws was terrifying.  I did not know what to do, but on impulse, I kept running.  Mercifully he opened his jaws within a few moments and to my surprise, let me go.  After I had put a few hundred metres between myself and my attacker I stopped to inspect the damage.  Apart from the lacerations where the teeth had gripped my forearm, I was unharmed.

So here I was again, in a similar situation.  This time the dog was even bigger but he hadn’t yet sunk his teeth into me. So I just kept running, trying to create an impression of calm confidence.  I continued to focus on opposing my thumb lightly against my forefinger as each arm swept down in turn towards my waist, to facilitate a neatly timed, relaxed footfall.  I was aware of the dog’s jaw impacting with my ankle but he didn’t get a grip.  I was also aware that my heart thumped in my chest.  As I continued running with an outward appearance of calm, I could hear a distant female voice calling.  It was apparently the dog’s owner, and he abandoned the pursuit.  I had no wish to invite any more trouble so continued on my way.

Later in the day when I examined the recording from my heart rate monitor I was both dismayed and amused to see the record of how my heart had responded.  The relevant segment of the record in shown in the figure.  There was a dramatic paroxysm in which my heart rate fluctuated crazily for about 10 seconds, but then settled back into a regular rhythm, just a little faster than before the attack.  Within half a minute it was back to its usual level.  While the heart trace demonstrates that I did not succeed in maintaining a perfectly harmonious physical and mental state throughout, it appeared I had done reasonable well in recovering my equilibrium.  I will never know just how intent the dog was on bringing me down, or indeed whether he was merely issuing a warning as the Alsatian had a year earlier, but I am pleased to know that I managed to remain calm and fairly confident with scarcely a perceptible adjustment of my stride.

Re-covering heart rate equilibrium after eluding the jaws of a Great Dane

Conclusion

In summary, if one wants to run at one’s best, establishing the ability to create the circumstances that facilitate this centred harmonious, virtually effortless and confident mental state is a crucial complement to the tasks of developing aerobic capacity, strength and skill.  Many of my most memorable running experiences over the years have been associated with this magical zone.  I hope that even as my strength ebbs with the passing years I will still retain ability to evoke this state.

I believe that many great athletes, among them sprinters such as Usain Bolt but also marathon runners such as Wilson Kipsang, have the knack of summoning this mental state.  Whether or not Kipsang will achieve it again in London in October this year is not certain, but as I watched that video of his run in Frankfurt, it appeared to me almost certain that sometime within the next year or two he will eclipse Patrick Makau’s world record.

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The Enigmatic Benefits of Pose

April 22, 2012

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.

Running naturally using sense and science

April 11, 2012

A few months ago I had a fairly clear idea about the content of my next few blog posts: my debate with Robert over the New Year period (recorded at length in the comments section of my Dance with the Devil article) had prompted me to tackle the issue of applying Newton’s equations of motion to running in a systematic manner, so my immediate priority at that time was a few technical articles on the mechanics of running.  After those articles, I intended to return to the issues of developing aerobic fitness; the influence of hormones such as growth hormone on tissue repair and regeneration; and some further accounts of my experiences with monitoring my heart rate.   This broad sketch is still on the drawing board but I have been waylaid by many interesting diversions. Apart from one post on the heart of the runner, that I felt could not wait too long because it was, in a way, my tribute to John Hadd, who had died while running a few months earlier, my posts this year have been heavily focussed on Newtonian mechanics, but many aspects of running mechanics remain untouched.

I anticipated that after the main article, posted on January 16th, in which I outlined the application of Newton’s equations to the motion of the runner’s centre of gravity (COG) and demonstrated the inevitable reality that getting airborne efficiently – the essence of efficient running – demands a short, sharp push against the ground, that I would easily tie up a few loose ends: important issues such a identifying optimum cadence and more peripheral issues such as dealing with wind resistance; but I had under-estimated the magnitude of the task.  In that first article, I had alluded in passing to the energy cost of repositioning the swing leg.  However I intended to by-pass this tricky topic by focussing on low to moderate speeds where repositioning costs are a minor fraction of the total energy cost.  However, Simon, whom I had come to know, at least in cyberspace, as a kindred spirit sharing a sceptical fascination with Pose technique, would not let me get away so easily with ignoring repositioning costs.  Others have jointed the debate from various perspectives, and as a result, I am still far short of my initial goal of reviewing the implications of Newton’s equations.  I continue to ponder the issues of aerobic fitness, tissue regeneration and heart rhythms, but my planned updates on these topics have been delayed.

The conundrum of the push

However, I have not been able to ignore another issue.  The conundrum that it is almost certain that for most runners, conscious focus on delivering a short, sharp push against the ground is not the best way to run safely and efficiently, except perhaps when sprinting.  It is this conundrum that has fuelled my long-standing fascination with Pose.  Despite the ‘looney-toon’ cartoon physics proposed by Dr Romanov in his book, ‘Pose Method of Running’, and unfortunately still lingering in articles on the Pose Tech website, there is little doubt that this irrationally-inspired running technique  has helped a large number of recreational runners to enjoy safer, more satisfying running.  There have also been many individuals disillusioned by being told by Pose coaches that their Achilles tendon injuries are simply due to not doing Pose properly, and others who have been disappointed that their race performances have not improved in the way they had hoped.  However, there does appear to be some magical injury-reducing ingredients in Pose.  One of these is the necessity to cut one’s training volume while developing the skill to perform the technique.  Furthermore, the reduced stress on the knee is an easily understood consequence of the Pose emphasis on forefoot or midfoot landing, though ironically it is the forefoot landing that puts the Achilles at risk.   The recommendation of high cadence reduces the magnitude of the force required for each step.  However, I think an even more important issue is the fact that the illusion that gravity provides ‘free energy’ allows Pose runners to achieve the essential short-sharp push against the ground without trying.

The secret

Is there a secret?  Many comments that have appeared on internet discussion threads in recent years imply that the secret lies in ignoring the physics; that  it is subjective experience that counts;   that we should perhaps revert to the noble primeval state of our Palaeolithic ancestors who are thought to have engaged in persistence hunting, barefoot, on the African savannah two million years ago.  The core idea is that thinking about what you are doing gets in the way of doing it.  In fact I strongly agree that attempting to exert conscious control over skills that our unconscious brain has learned to perform is often counter-productive.  However I do not believe that the secret is to revert to a primeval Palaeolithic state.  In fact I do not believe that would be natural.  In the two million or so years that separate early members of the Homo genus, such as Homo erectus who apparently had developed the musculo-skeletal features necessary for endurance running, from Homo sapiens with his/her large skull, we have developed an extraordinary capacity to achieve our goals, a capacity residing largely in our brains.

For several millennia, this capacity was strongly shaped by spirituality.  In the video recording of persistence hunting in our own era by bushmen in the Kalahari, narrated by David Attenborough, there is a moving moment near the end, after the quarry has been killed, in which the hunter strokes the head of the dead animal in acknowledgment of the spirit with which it had eluded its pursuer in an eight hour run across the savannah.   Spirituality is a key human persisting attribute.  If we are to be truly in tune with our own nature, we need to find a way to integrate the legacy we have received from our Palaeolithic ancestors with the capacity for science that is embodied in Newtonian mechanics.  For the present discussion, we can put aside relativity, quantum mechanics, and string theory.  Our Palaeolithic ancestors, perhaps unencumbered by too much weighty remembrance of the past or planning for the future, lived much more in the present moment, in which sensations not only of sight and sound, but also the sensations of the body in its environment, dominated awareness.  Can we run in a way that utilises both sense and science?

John Woodward, a practitioner of the Alexander Technique based in the Lake District where he teaches the art of running barefoot across the Lakeland fells, summarises the challenge: ‘.. in our modern lives our thinking caps (our heads) have become disengaged from our kinesthetic (body) sense. Unlike our ancient ancestor we are rarely in the vivifying moment but we languish in some past memory or crave some future state.’

Feldenkrais

I have been diverted into this train of thought by some challenging questions and comments on my article  on Natural Running (posted  on 29th March), especially by Hans, a Feldenkreis practitioner who had attempted various ways to escape his previous injury-prone running style before trying Pose, under the guidance of Jeremy Huffman.  Jeremy is an elite athlete with a sub-4 minute indoor mile to his credit, who has subsequently become a strong advocate of Pose, and frequently comments on this blog.  Jeremy helped Hans find the practical answer he was seeking, but left him with the challenge of understanding how Pose had worked while Feldenkrais had not.   Feldenkrais had been developed by Moshe Feldenkrais, who was an engineer who attempted to integrate a sound scientific understanding of human movement with a holistic awareness of one’s body in space.  Moshe Feldenkrias did not develop a theory of running but others, such as Feldenkrais practitioner, Jae Gruenke, have done so.  Hans concluded the emphasis on avoiding driving and pushing was a key issue in the success of Pose.  In his comments on my blog he initially questioned the necessity of the push.  After we had discussed a number of actual and hypothetical experiments that he devised, he was willing to accept that the push occurs, but proposed that the action of the leg might best be described and experienced as springy, rather than a push movement.  He agreed that that muscle work is involved in creating the springy effect, but this could happen without conscious effort

I agree that it is desirable to maximise the recovery of energy via elastic recoil, and certainly accept that it is best to let this occur with minimal conscious effort.   However, my own view is that we need a somewhat more comprehensive approach.  I think that it is best to cultivate a holistic perception of one’s body in space while applying a range of principles that are derived not only from physics and muscle physiology but also from neuroscience.

Some background

Perhaps it is time to give a little more detail about my background.  I began my scientific career as a physicist over forty years ago and subsequently have been fortunate enough to have had the opportunity do research in many different fields of science.  From physics I moved to biochemistry, or rather I integrated physics with biochemistry while holding joint academic posts in physics and biology.  Eventually, after several decades of diverse scientific and clinical experiences, I became what might be most accurately described as a neuroscientist, though I have always resisted labelling myself as a practitioner of a single discipline.  In the early 1990’s I was involved in some of the earliest investigations using modern brain imaging techniques to attempt to delineate the brain mechanism associated with willed action.  Since then I have continued to study brain function, mainly focussing on the conscious processing of information.  I am certainly not an expert in either the perceptual or motor systems in the brain.  Nonetheless, in some of my recent work using brain imaging techniques combined with electroencephalography (EEG), I have investigated the way in which the perception of bodily sensation engages the brain’s executive systems.

Although this work is exciting and high tech, it is also extremely primitive.   Indeed, while I am confident that neuroscience will furnish us with concepts that help us to understand many of the types of processes that go on in our minds and bodies, I believe it will never provide an understanding that matches the richness and diversity of personal experience.

In the days when I was doing my PhD in physics, I was also a marathon runner and a mountaineer.   Though physics, running, and spending time in the mountains were an integral part of my life, there were only a few strands that linked these activities.   Over the years, the rest of life’s activities displaced the running and, eventually, the adventurous aspects of mountaineering.  However nowadays I am once again running and also enjoying the hills and mountains, while I am still a scientist.  My forays into the intricacies of the human mind and brain have given me a slightly firmer foundation from which to try to integrate science, running and an appreciation of the natural world

The messages from neuroscience

Perhaps the most relevant message from cognitive neuroscience to the runner is that we can only focus consciously on a very small number of items of information at any one time, but the neural representation of many other aspects of a situation can be subliminally active in the background.  Furthermore, our brains are exquisitely sensitive to unexpected events. Thus we cannot focus on all of the aspects of running mechanics within a single gait cycle, but if we have practiced the actions and experienced the sensations often enough, the neural representation of most aspects of running are subliminally active, and are likely to enter into conscious awareness if the expected rhythm misses a beat.  In an attempt to instil the expectation of the pattern of activity involved in the swing of the leg from one stance to the next, I practice drills such as the Swing Drill.

The next important point emerges from our understanding of the sensori-motor systems: modern brain imaging has consolidated the observation of neurosurgeon Wilder Penfield at the Montreal Neurological Institute in the 1930’s, that the brain allocates far more of its processing resources to the hand than to the foot.   The region of the motor cortex devoted to the hand  is far greater in area than that devoted to the foot.  However, our brain can learn to integrate a complex set of muscle contraction into a single action.  Therefore, it is plausible that if we can link a set of movement of the hand to a set of movement of the leg and foot, we might be able to control this complex but integrated action more precisely.  Therefore I practice a version of the Change of Stance drill to establish in my brain a non-conscious motor program that combines a down sweep of my hand from a position near the sternum high on my chest wall towards my waist, with a quick extension of the flexed hip and knee of my elevated leg to the ground.  As I sweep my hand down, I hold forefinger and thumb lightly opposed to inculcate a sense of tidy but relaxed movement.  When I run, I rarely attend consciously to the extension of hip or knee but focus mainly on this brisk but relaxed and economical down-sweep of the hand.

This was the final sprint in a half-marathon a few years ago. I am 4449. The strain of running with a torn hip adductor, wrenched during a clumsy turn near the halfway mark, shows in the tense muscles in my neck and left shoulder, but the right hand, with forefinger and thumb lightly opposed at my waist is fairly well coordinated with the (non-conscious) push of my left leg.

The next important point to learn from the way in which our brain develops from infancy to adulthood, is that we learn how to detach unnecessary movement from a motor act.  A young child, when trying to do some intricate task with one hand, often exhibits mirror movements with the other.  Although we usually avoid this in adulthood, at times of stress, we are prone to introduce unnecessary movements.  Perhaps Paula Radcliffe’s tortuous movements of the neck during her 10,000m races in the late 1990’s were an illustration of this.  You can also see it in the picture of me.  However we have the capacity to release tension in unneeded muscles.    When I run I cultivate an awareness of the tension in my shoulder muscles, aiming for a sensation of the trapezius muscle relaxing to allowing my shoulders to relax downwards and slightly back.

I also find it helpful to maintain awareness of the pattern of pressure on the soles of my feet during stance, and to adjust this according to terrain and speed.  I do not run barefoot, except for short distances on grass, but do wear fairly light-weight shoes.

I regulate my level of energy expenditure largely by awareness of my breathing.  When breathing comfortably at a rate of one breath every six steps (about 30 breaths per minute),  I know I am in the lower aerobic zone, with minimal accumulation of acidity in my blood stream.  I can run for hours at this pace.  When my breathing rate increases to one every four steps, there has been mild accumulation of acid, but my body is dealing with it.  Nowadays I will be struggling after an hour at this pace, though a few years ago I could maintain this pace for about two hours.  When breathing rate becomes one breath every two steps, the acidity is accumulating rapidly.  This is only OK for the final stages of a race, or during high intensity intervals.

Some of these aspects of body awareness are well known to coaches and athletes; others, such as my focus on the down sweeping hand are experimental.  The over-arching principle is the cultivation of a holistic awareness of the sensations and movements involved in running, allowing for effort in the right time and place, while maintaining an overall sense of light, relaxed progress across the ground.

Final thoughts 

Here is John Woodward again, describing a workshop that he and his colleagues offer: ‘We perpetually stream down one route – the mechanical one: WE RUN MECHANICALLY. The aim of the workshop is to first and foremost stop the flow of traffic down the mechanical road the route well travelled. Like repositioning the points on the railway we want to initiate a flow down the road less travelled. This will enable the Thinking Gear to re-synchronize once more with the body. In this way we might begin to run creatively. There’s a number of key things about this invitation to re-route the traffic onto the road less travelled, the road to the present moment.’

I am not fully in tune with all of this statement.  I do not think we need to stop the traffic flow on the mechanical path.  I think the word ‘synchronise’ is the key concept. If we, as members of the species Homo sapiens, are to run truly naturally we need to find a way of synchronising the two routes: the mechanical path guided by knowledge and shaped by practice, and the path through sensations in the present moment.  I am still at the beginning of working out how this might be done.  My current experiments in running holistically might be clumsy, half-blinded attempts towards the goal.  I will value any comments.

Note added 12 April 2012

With regard to the proposal that it might be desirable develop a holistic sense of what is happening to the body, even though our attention is not focussed consciously on every aspect, there is a very informative picture in today’s Guardian newspaper, showing Prince Harry and Usain Bolt being silly for the sake of a photo-opportunity.  http://www.guardian.co.uk/uk/2012/apr/11/how-the-royals-became-cool   They are imitating a well known advertisement for Richard Branson’s company, Virgin. In the advertisement, Branson’s face is superimposed on Bolt’s body, as he mimes shooting an arrow from a bow.  In this Guardian photo of Harry and Bolt, note how the index finger of Bolt’s right hand is aligned perfectly with the index finger of his left hand.  I suspect he wasn’t consciously thinking about this as he posed for the photo.  Simply, his brain has an extremely good sense of where the ends of his limbs are at all times.  I think that is one of the reasons Bolt is the world’s fastest sprinter.  I think we can improve our running by improving our bodily awareness. In particular, awareness of the end of the index finger can probably associated with subliminal awareness of the location of the foot.

Is there a magic running cadence?

April 5, 2012

The six posts in my recent discussion of running mechanics, starting with my presentation of the equations of motion of the runner on 16th of January, have elicited 372 comments (including my own responses to the comments of others).  I have been delighted by the vigour of the discussion, but am intrigued by the fact that of these posts, the one which elicited the least comment was my post on the increased efficiency associated with increased cadence, on 6th February, which elicited only 5 comments.   I suspect that this relative paucity of comments reflects a widespread acceptance that increasing cadence does improve efficiency.  The major issues in the other five posts were related to the question of the push that is required to get airborne.  This appears to be a far more controversial topic.

From my own perspective, the controversy regarding push rather than cadence is a peculiar inversion of the uncertainties of running mechanics.  The fact that a large push is required to get airborne can be demonstrated by simple application of the laws of physics, and is readily confirmed by examination of force plate data.  A large vertical push makes it possible to minimise braking.  However, elastic recoil can produce at most 50% of the required energy for the push, so the vertical push is not cost free.  I suspect that the controversy about push exists because many runners, especially those who have adopted the Pose style, have found that they suffer less injury when they do not focus consciously on pushing.  Of course avoiding thinking about the push does not stop it happening.   But the evidence does suggest that avoiding thinking about it does reduce the risk of some common types of injury.  My own view is that denying the occurrence of a large push creates a different set of risks, and therefore I think that the challenging goal of developing a safe efficient running style is creating a mental image that allows a runner to avoid a mis-timed push and other associated unnecessary muscle activity, without the need to deny the existence of strong push.

The question of how to develop the optimum mental image is a question I will certainly return to in future.   The question that currently intrigues me is the apparently widespread acceptance that high cadence is generally good (a view that I myself advocate, but with reservations).  This view does not account for the clear evidence that most runners employ a relatively low cadence at low speed and increase as they increase speed.   While it is commonly believed that a cadence of 180 steps per minute (or 90 gait cycles per minute) is the optimum cacence, it is noteworthy that the representative runner depicted in figure 2 of Weyand’s paper (J appl Physiol, 89, 1991-1999, 200) increases cadence for about 144 steps per minute at a speed of 3.5 m/sec to 234 steps per minute at a speed 9.5 m/sec.  In my experience, these values are typical.   While many runners have a cadence around 140 steps /min or less when jogging, elite sprinters usually exceed 250 steps/min at top speed.   Therefore, the view that there is a target cadence of180 steps/min only corresponds very loosely with what runners do.

There is an optimum cadence for a given speed and peak vGRF

To estimate the most efficient cadence for a particular speed it is necessary to compute all three of the major costs of running: elevating the body, overcoming braking, and re-positioning the limbs.  While the combined costs of elevating the body and overcoming braking generally decrease with increasing cadence, the costs of repositioning the limbs increases with increasing cadence and also with increasing running speed (see calculations page, in the side bar, where I demonstrate that a fairly accurate estimate of the repositioing costs per Km per Kg body mass is given by 1.32CV Newton-metres where C is cadence in steps / min and V is running speed in metre/sec  ).  Therefore, for a given speed and peak value of vertical Ground Reaction Force (vGRF), there will be certain cadence at which the total energy cost will be minimised.  In other words, total energy costs decrease as cadence increases up to a certain point, but after the point at which the increasing cost of accelerating the swing leg outweighs the saving in the sum of elevation and braking costs, further increase in cadence will lead to greater costs.

Optimum cadence depends on ability to push

However, there is no single optimum value for cadence. The optimum cadence depends on one’s ability to exert a well timed strong push.  Elevation and braking costs decrease with increasing peak vGRF at a particular velocity, so the cadence at which the repositioning cost outweigh the elevation and braking costs at that velocity, will occur at a lower cadence in a runner who can exert a stronger push.  As the cost of accelerating the swing leg is lower at a lower cadence, peak efficiency will be greater in a runner who is capable of exerting a greater peak vGRF thereby achieving peak efficiency at lower cadence.  In other words, we can increase efficiency by developing the ability to exert a stronger push, provided the push is delivered at the right time and without producing unnecessary contraction of other muscles.

A comparison of age with youth

The computations that I presented on 6th February, clearly demonstrated that at a speed of 4 m/sec, the combined cost of overcoming braking and getting airborne is less at a cadence of 200 steps per minute than at 180 steps per minute, when the peak vGRF is 3 times body weight.  In fact, I myself adopt a cadence a little over 200 steps per minute at a speed of 4 m/sec, but most runners do not adopt such a high cadence at this modest speed.  I do so because, being a 66 year old with failing muscle strength, I find it difficult to exert a push against the ground of more than 3 times my body weight without straining.   Many younger athletes can easily exceed a peak push of this magnitude without consciously trying.  I am currently trying to increase my ability to achieve a stronger, well coordinated peak push, both by means of increasing my muscle strength, and also by improving the coordination of the push.

Recently Ewen pointed out on his blog that in setting the British 3000m indoor record of 7:40.99  in Glasgow in 2009, Mo Farah exhibited a cadence of only 176 steps/min in mid-race when he was covering each Km in about 2:35 (almost 6.5 m/sec).  He did increase to a cadence of around 187 in final few laps.

It appears that Mo is able to achieve a high efficiency at a relatively low cadence.  This demonstrates that he is capable of exerting an exceptionally strong, well coordinated push.

Conclusion

In summary, while the combined cost of elevation and braking decrease with increasing cadence, the cost of accelerating the swing leg increases with increasing cadence.  The total cost of elevation, braking and accelerating the swinging leg will decrease as cadence increases up to a certain limit, but beyond the point where rate of increase in swing costs outweighs the saving in elevation and braking cost, increasing cadence results in increasing cost.   A runner who is able to deliver a well-timed large push without simultaneously contracting unnecessary muscles can achieve peak efficiency at a relatively low cadence.