‘Scientific evidence’ part 2 – misplaced faith in meta analysis

“He uses statistics like a drunken man uses a lamppost, for support rather than illumination”

Mark Twain

img92In the absence of the context provided by natural laws, and the credibility conferred by replication, modern science has turned to the meta analysis approach to judge what ought to be taken as ‘best available’ evidence. Meta analysis is a statistical procedure that combines individual studies on a topic. The studies entered into the meta analysis often have a wide range of outcomes as each study contains different individuals and sometimes different ways of measuring the outcome of interest. The goal of meta analysis is to derive a new ‘overall’ result that supposedly represents one huge study with a much larger sample. It is the top of the evidence-based pyramid and is believed to provide the most trustworthy facts / evidence. However, like all statistical procedures, the output is only as good as the input. Given that there is heavy publication bias in journals towards positive effects, with replications and zero-effect studies not being represented (Rosenthal, 1979) meta analyses outcomes are also highly likely to be biased (Oakes, 1986). In the world of evidence-based practice, this is known as bias in = bias out, or the BIBO monster. This is using statistics for support not illumination.

So what is credible, trustworthy scientific evidence?

Trustworthy scientific evidence is:

  1. That which agrees with natural laws and
  2. After satisfying 1, that which has been replicated many times in different samples but with the same or a similar result.

Applying these simple filters can help anyone to avoid confusion in the face of equivocal research findings, and to avoid being duped by the latest craze / fad / fashion. The BTR model is based solely on scientific evidence fitting this definition i.e. trustworthy, credible and undisputed.

References.

Oakes, M. (1986). Statistical Inference: A commentary for the social and behavioural sciences. New York: John Wiley & Sons.

Rosenthal, R. (1979). The “File Drawer” problem and tolerance for null results. Psychological Bulletin, 86(3), 638-641.

‘Scientific evidence’ part 1 – old versus new ‘science’

“Science is built up of facts as a house is with stones. But a collection of facts is no more a science than a heap of stones is a house”. (Henri Poincare, 1904)

In 1963, B.K. Forscher wrote a letter to the editor of the esteemed journal Science titled “Chaos in the Brickyard”. The letter expressed his concerns about the proliferation of meaningless studies that failed to adhere to the sound theory-building ideals of the scientific method. The situation has not improved. Indeed, with the advent of the so-called ‘evidence-based model’ for judging the value of ‘facts’, the situation has worsened dramatically.

Old approach to ‘science’

Before the term ‘scientist’ came into being, natural philosophy was the term used to describe the study of nature and attempts to understand and explain natural phenomena through observation, theory formation, and evaluation of predictions of those theories against nature using inductive reasoning to decide if the predictions and their parent theory were supported or not. Popper (1980) advanced this approach with his ‘falsification’ ideal, allowing the use of deductive reasoning to decide if theories had been falsified in light of data, or had survived to be possibly disproven another day (read confirmation bias post). Both falsifications and survivals were published and presented to other natural philosophers, who attempted to replicate the survivals in particular. If a positive finding was repeated many times and not once falsified, that theory was accepted as relatively trustworthy ‘evidence’. In fact, theories that survived many years of such practice were elevated to the status of ‘natural laws’. These ‘natural laws’ were used to drive further theory formation, and to act as ‘validity checks’ of findings from new investigations, i.e. if a new fact violated an existing and undisputed law, its value was questionable. Furthermore, if the new finding could not be replicated, it was deemed a fluke and so, of little value to the body of trusted ‘evidence’.

New approach to ‘science’

Forscher (1963) recognised the deterioration of the rigorous ‘old-science’ approach many decades ago, highlighting that modern ‘scientists’ were inclined to simply churn out investigations that were not based on careful theory building, and were not evaluated against accepted-trustworthy ‘evidence’. Faith in ‘science’ was apparently restored by the development of the ‘evidence-based-practice model’ that has since spawned organisations like the Cochrane Collaboration and journals based on its principles (e.g. Evidence-based Medicine). Rather than judging the value of investigations against undisputed laws, as in natural philosophy, the evidence-based model assesses trustworthiness and value based on the rigour of the research design and experimental  approach, trusting that statistical principles and elimination of confounding factors will ensure validity of new ‘facts’ (more about the problems with this in part 2). Old fashioned replication is discouraged by editors of journals who refuse to publish work that is not ‘novel or original’. Negative / falsifying findings are also unlikely to be seen by others as they are deemed of little interest compared to ‘positive’ findings which, without replication, could simply be flukes. In fact, a recent and high-profile investigation of the replicability of scientific publications found that of 100 previously-published-positive findings, only 36% could be reproduced (Nosek et al., 2015). The failure to judge the value of new ‘evidence’ against established ‘laws’ leads precisely to the problems raised by Forscher (1963) and by Poincare over a century ago i.e. a collection of useless ‘facts’ without the context that alone makes for useful ‘evidence’.

btr-old-new-science

Criticisms of the evidence-based model

Many areas of modern ‘science’ are characterised by lack of consensus and equivocal findings, with the latest ‘understanding’ often changing on a weekly basis with the latest new piece of research. Running injury causes and cures and dietary recommendations are two prime examples. The lack of context in the evidence-based model, and the failure to dismiss shiny-new ‘facts’ and fads that cannot be replicated and / or make no sense against undisputed laws, is the explanation for this. It is for these (and other) reasons that evidence-based practice has been widely criticised with arguments that are well established, including nonsensical findings (Britton et al., 1998; Strauss and McAlister, 2000; Mullen and Streiner, 2004). The nonsensical findings and the lack of consensus characteristic of modern ‘evidence’ are highlighted beautifully by an old joke of the couple who visit their rabbi for marital advice:

The husband delivers a long list of complaints about his wife, to which the rabbi replies, “You’re right, you’re right.”

The wife then gives her long list of complaints about her husband, to which the rabbi replies,“You’re right, you’re right.”

About to leave, the wife yells at the rabbi, “How can you tell us both that we’re right? One of us must be wrong!”; to which the rabbi replies “You’re right, you’re right.”

How to avoid being buried alive in the pile of equivocal ‘facts’

The majority of the most significant discoveries in the history of science (the ‘laws’) were discovered long before evidence-based practice reared its ugly head. These discoveries were made using old methods of natural philosophy, based on solid theory, and guided by natural laws. We should heed the words of Poincare and Froscher and choose our stones / bricks carefully from the pile / brickyard. Only then can we build something that looks and functions like a house. It is from such carefully-selected bricks that the foundations of BTR and the walls of its wisdom are built.

References

Poincare, H. (1904). Science and Hypothesis. Dover: Walter Scott Publishing Co.

Forscher, B.K. (1963). Chaos in the brickyard. Science, 142, 339.

Popper, K (1980). The Logic of Scientific Discovery (10th Ed). London: Hutchinson

Nosek, B.A. et al. (2015). Estimating the reproducibility of psychological science. Science, 349 (6251), aac4716.

Britton, B.J., Evan, J.G and Potter, J.M. (1998). Does the fly matter? The CRACKPOT study in evidence based trout fishing. British Medical Journal, 317, 1678-1680.

Strauss, S.E. and McAlister, F.A. (2000). Evidence-based medicine: A commentary on common criticisms. Canadian Medical Association Journal, 163, 837-841.

Mullen, E.J. and Streiner, D.L. (2004). Evidence for and against evidence-based practice. Brief Treatment and Crisis Intervention, 4, 111-121.

 

 

Harvard research supports BTR coaching wisdom

Professor Dan Lieberman’s latest publication supports the Born to Run coaching philosophy

Lee Saxby’s Born to Run coaching system emphasizes the detrimental effects of over stride both on injury risk and on running economy. Lee made the connection between over stride and running rhythm / stride frequency a long time ago and subsequently made rhythm the second priority in his ‘posture-rhythm-relaxation’ movement mantra.

About the study

The study examined the relationships between stride frequency, over stride, braking forces, peak-impact forces and loading rates, and the energy cost of running at a fixed speed (3.0 m/s) in 14 experienced runners. Participants were asked to run on a treadmill with stride frequencies of 75, 80, 85, 90 and 95 strides/min. Ground-reaction forces, lower-extremity joint angles and the metabolic cost of running were measured.

What the study showed

  • For every increase of 5 strides/min, the energy cost of swinging the leg forwards (estimated from maximum-hip-flexion moment) increased by 5.8%, and over stride (landing position of the foot relative to the hip) decreased by 5.9%
  • Larger over stride associated with higher braking (backwards oriented) forces and with higher peak-vertical-ground-reaction forces
  • Metabolically-optimal (least costly) stride frequency was around 85-90 strides/min (170-180 steps/min)

Take home message

Increased stride frequency (within optimal range) decreases over stride and, in turn, decreases braking force and peak-vertical-impact force that are related to injury risk. In addition to reduced braking and impact forces, stride frequency within the BTR recommended range decreases the metabolic cost of running.

References

Lieberman, D.E., Warrener, A.G., Wang, J. and Castillo, E.R. (2015). Effects of stride frequency and foot position at landing on braking force, hip torque, impact peak force and the metabolic cost of running in humans. Journal of Experimental Biology, 218, 3406-3414.

Paper available HERE.

The science of falling

Who has seen the wind? Neither you nor I, but when the trees bow down their heads, the wind is passing by”. (Rossetti, 1915).

The Science of Falling: How a virtual pivot point explains constant-velocity running using gravitational torque. 

In part 3 of the series of posts on the extensor paradox, it was concluded that gravity creates a turning force or torque on the center of mass of a runner about the supporting foot, when the former passes in front of the latter. It was also concluded that this gravitational torque provides the motive force in running. This theory is in agreement with kinetic and EMG data from previously published research (Mann et al., 1986; Rodano, 1987; McClay et al., 1990), whereas the prevailing theory that runners actively ‘push’ into the ground is at odds with both – hence the so-called extensor paradox that is not a paradox at all.

The theory that gravity provides the motive force in running is not new (Morton, 1935; Perry, 1992; Romanov and Fletcher, 2007). However, the mechanism used to explain the action of gravitational torque in these publications struggle to explain constant-velocity running, and instead would lead to constant acceleration, closer to what happens when sprinters initially leave the blocks, and as depicted in part three of the extensor paradox post. A recent attempt to explain gravitational torque in locomotion, and to experimentally demonstrate it’s effectiveness in reducing the energy cost of running and walking (Kanstad and Kononoff, 2015), suffers from fatal methodological issues and reporting bias. Constant-velocity running, as well as acceleration and deceleration using gravitational torque can, however, be perfectly explained by the virtual pivot point model (VPP) (Maus et al., 2010). This model also explains the stability observed in what ought to be a very unstable gait.

Unstable bipeds and running robots

The VPP model has its origins in engineering and was borne out of the seemingly insurmountable problem of preventing an inherently-unstable-bipedal robot locomote without falling over. Keeping a heavy torso upright over a long leg with a small base of support is a complex task amidst the varied forces acting on it during the running cycle. It is no less a challenge for humans, yet healthy humans rarely fall over. The solution lies in aligning the ground reaction force vector with a fixed, though virtual axis high in the torso, above the center of mass, at every stage of the stance phase. This is the virtual pivot point model.

The VPP and constant-velocity running

 

Science of falling VPP_corection hq_muscles

The image above depicts a runner at initial ground contact (left), mid stance (middle), and terminal stance (right). The graphs below show the vertical ground reaction force and torque about the hip joint respectively. At initial ground contact, the GRF vector is angled backwards and up through the VPP and in front of the center of mass (producing a slight braking effect). The perpendicular distance between the GRF vector and the hip joint is shown as D. This discrepancy creates a hip flexion torque and a forward pitching of the torso that must be controlled by hip extensors. The shaded region about the rear of the hip and lower back illustrate the EMG response of the hip extensors whose primary purpose (see teleology post) is to control the forward pitch of the torso in running, hence their extensive development in humans but not non-running apes and chimps (Lieberman et al., 2006). This slight forward pitch of the torso is evident in slow-motion observations of every elite runner and was leveled as a criticism of the ‘Pose’ conception of running (Brodie et al., 2007).  At mid stance, the GRF vector is vertically-aligned with the hip, center of mass and VPP. The EMG activity shown in the legs here is simply to resist the squash of gravity and the opposing GRF and to aid storage of energy in the major tendons of the leg. Immediately after mid stance, the extensor muscles switch off and the runner’s center of mass falls forward using gravitational torque at the same time as the leg spring passively recoils providing the upward motion seen in the trajectory of the center of mass. This time, the GRF is aligned forwards and up through the VPP and behind the CoM and hip, creating acceleration, and a hip extension torque that activates hip and trunk flexor muscles and begins the recovery of the support leg. There is also a resulting backwards pitch of the torso, which again, can be seen in slow-motion footage of all good runners. The figure shows how the GRF vectors at initial contact and terminal stance are exactly opposite each other creating equal but opposite hip flexion and extension torques and a constant velocity i.e. the slight braking effect is counteracted by the acceleration effect provided by gravitational torque after mid stance. Acceleration and deceleration result from mismatches in the hip flexion and extension torques.

The VPP model explains and accounts for kinetic and kinematic observations of human and animal runners and how they work with gravity, to save energy, as predicted by the biological imperative. Predictions of the theory have been supported by observations in rigorously-designed studies. A theory that explains and account for all observations is of course superior to one that does not. The current ‘runners push’ theory, and past and recent ‘gravitational torque’ theories constitute the latter.

References:

Brodie, M., Walmsley, A., and Page, W. (2007). Coments on “Runners do not push off but fall forward via a gravitational torque” (Vol. 6, pp. 434-452). Sports Biomechanics, 7(3), 403-405.

Kanstad, S.V. and Kononoff, A. (2015). Gravity-driven horizontal locomotion: theory and experiment. Proceedings of the Royal Society A, 471(20150287), 2-11.

Lieberman, D.E., Raichlen, D.A. and Pontzer, H. (2006). The human gluteus maximus and its role in running. Journal of Experimental Biology, 209, 2143-2155.

Mann, R.A., Moran, G.T. and  Dougherty, S.E. (1986). Comparative electromyography of the lower extremity in jogging, running and sprinting. The American Journal of Sports Medicine. 14(6), 501-510.

Maus, H.M., Lipfert, S.W., Gross, M., Rimmel, J and Seyfarth, A. (2010). Upright human gait did not provide a major mechanical challenge for our ancestors. Nature Communications, 1(70), 1-6.

McClay, I.S., Lake, M.J. and Cavanagh, P.R. (1990). Muscle activity in running. In P.R. Cavanagh (Ed.), Biomechanics of Distance Running (pp 165-186). Champaign, Illinois: Human Kinetics.

Morton, D.J. (1935). The Human Foot: its evolution, physiology and functional disorders. New York: Columbia University Press.

Perry, J. (1992). Gait Analysis: Normal and Pathological Function. Thorofare, New Jersey: SLACK Inc.

Rodano, R. (1987). Evaluation of movement in sport by means of vectograms. International Symposium on Biomechanics in Sports, 506-522.

Romanov, N and Fletcher, G. (2007). Runners do not push off the ground but fall forwards via a gravitational torque. Sports Biomechanics, 6(3), 434-452.

Rossetti, C.G. (1915). Sing-song: a nursery rhyme book. London: MacMillan and Co.

The Extensor Paradox – but not really Part 3 of 3

Motion is created by the destruction of balance, that is, of equality of weight, for nothing can move by itself which does not leave its state of balance, and that thing moves most rapidly which is furthest from its balance” (Leonardo Da Vinci, 1452).

Part 2 of this series closed with a statement that gravity is the motive force in terrestrial locomotion. Parts 1 and 2 provided evidence disproving the existence of an active push in accelerating the center of mass forwards. In this final part of the series, gravity, or more specifically, torque created by gravity, will be shown to provide forward acceleration of the center of mass according to the undisputed-fundamental laws of physics.

Destruction of balance creates acceleration by gravitational torque.

btr-drestuction-of-balanceThe object in A is in balance / stationary, with its center of mass (the cross) vertically aligned over its stationary point of support. In B, the center of mass of the object is out of alignment with the stationary point of support. Gravity acts on the center of mass, creating a turning force (torque) about the point of support as an axis. Left alone, the center of mass will continue to accelerate at 9.81 m/s every second (i.e. constantly increasing speed), until the object hits the ground. The further the center of mass of the object from its point of support, the greater the gravitational torque and the faster the center of mass will fall. This is GRAVITATIONAL TORQUE.

Picturing gravitational torque in locomotion.

btr-grav-torque-locomotion

The figure left is adapted from the work of Morton (1935). He labeled the tilted (away from the gravitational vector) line drawn from the point of support through the center of mass the ‘angle of instability’. From left to right, the figure shows a state of balance, moderate instability in walking and maximum instability in running. The forward acceleration in walking and running is provided by gravitational torque, acting on the center of mass around the stationary-supporting foot.

While the figure is useful to conceptualize how forward movement can result purely from gravity, without an active push, it is a gross oversimplification and has some critical problems that do not agree with observation. Nevertheless, this conception of how gravity can be a motive force has been used as the cornerstone of some schools of running, in particular, Pose technique (Romanov and Fletcher, 2007). While the general idea of gravitational torque as the motive force is correct, the mechanisms by which it acts have been incorrectly described.

The problem of constant acceleration.

As stated earlier, gravity accelerates mass continuously, so the idea of holding a fixed angle of lean at a constant velocity and simply increasing or decreasing the angle to accelerate or decelerate is flawed. Suppose a runner adopts an angle of instability of 15 degrees. As soon as this happens, his center of mass is accelerating under gravitational torque at an ever-increasing rate. Unless he is able to accelerate the recovery of his feet to match the rate at which his center of mass is falling away from his feet, the angle of instability will constantly increase and an imminent face plant is inevitable!

So near, yet so far, but the truth is out there.

The simple model of gravitational torque outlined above cannot account for constant-velocity running. By now, it should be clear that a theory at odds with evidence is, by definition, wrong. The ‘concept’ of gravitational torque must be true based on fundamental laws of physics. It is simply the case that the mechanism by which it operates in locomotion has been oversimplified. The true mechanism by which gravity acts as the motive force in locomotion is well accepted, but apparently not well known. It is the ‘Virtual-Pivot-Point model’. It explains all observations, has been used by engineers to create human-like running robots, and also explains why inherently-unstable bipeds are not as unstable as predicted.

For an explanation of the TRUE application of gravity as the motive force in locomotion, watch out for the ‘Science of Falling’ post coming along soon.

References:

Maus, H.M., Lipfert, S.W., Gross, M., Rimmel, J and Seyfarth, A. (2010). Upright human gait did not provide a major mechanical challenge for our ancestors. Nature Communications, 1(70), 1-6.

Morton, D.J. (1935). The Human Foot: its evolution, physiology and functional disorders. New York: Columbia University Press.

Romanov, N and Fletcher, G. (2007). Runners do not push off the ground but fall forwards via a gravitational torque. Sports Biomechanics, 6(3), 434-452.

The Extensor Paradox – but not really Part 2 of 3

“If there is an exception to a rule, and if it can be proved by observation, that rule is wrong” (Richard Feynman, 1963) 

The ‘rule’ addressed in this series of posts is that ‘runners push’ to propel themselves forwards. In part 1, experimental data showing the leg extensor muscles to be silent / switched off at the point of the stride cycle where they ought to be providing the ‘push’ was discussed. These data are the ‘exception’ to the pushing ‘rule’ and have been consistently repeated. So the rule is WRONG, there is no paradox. To quote from one of the key studies, “These experiments have, however, shown that the notion of an extensor thrust – with plantar flexors, knee extensors, and hip extensors all being active in late support to generate forward and upward thrust – is in need of modification” (McClay et al., 1990). And yet, some 25 years later, it is still the common belief that running involves actively pushing into the ground!

In addition to the absence of extensor-muscle activity some 30ms after ground contact, measurement of ground-reaction force data provides a further nail in the coffin of the ‘push’ theory. Newton’s 3rd law states that each action has an equal and opposite reaction. Thus, there is a force of equal magnitude but opposite direction produced by the ground in reaction to the runner’s impact with it. The size and direction of the ground reaction force can be measured and visualized using a vectogram. To understand a vectogram, it must be understood that a force has both magnitude (size) and direction (forwards and backwards, vertical, and lateral). The latter is generally ignored in analysis of human movement, as the largest forces occur in the vertical and horizontal planes. A vector of vertical and horizontal forces can be calculated and plotted. A vectogram of a single ground contact in a skilled runner is shown below along with the phases of the stride cycle. The magnitude of force is expressed in multiples of bodyweight with the vertical axis representing one bodyweight.

btr-extensor-pt2-vectogram

The figure shows many notable features:

  1. On impact, the ground reaction force is angled back at the runner and produces a braking effect that must be controlled using eccentric activity of the leg muscles, which also stores elastic energy in tendons.
  2. The magnitude of force rises as the runner’s centre of mass falls over the supporting foot, reaching a peak when the two are vertically aligned, the centre of mass is at its lowest point, and the runner is squashed between gravity and the ground-reaction force. This is also the point of peak muscle activity as the compression is resisted.
  3. After midstance, the extensors switch off, and force (from passive elastic recoil) rapidly falls
  4. When the direction of the ground reaction force is forwards, its magnitude is only a fraction of bodyweight and therefore insufficient to ‘propel’ the body weight. Leg muscle activity at this point is to recover the trail leg, to catch the runner on the next stride.

There is no push.

The ‘push’ paradigm states that runners actively create a downwards and backwards force with the leg extensors to drive them forwards and up into the next stride. For this ‘rule’ to be true, we should observe highly active extensors after midstance, and a ground-reaction force vector in excess of bodyweight when angled in the direction of travel. Instead, experimental data show the extensors to be silent and forces too small to ‘propel’ the runner in the direction of travel. There can be only one conclusion from these observations, THERE IS NO PUSH, just as there is no extensor paradox!

So what causes acceleration in running?

As unstable-terrestrial bipeds, bound by the biological imperative, it makes sense that we use the strongest force on the planet to cut the energetic cost of locomotion. In running as in walking, GRAVITY provides the motive force for movement. The final post in this series will explain how skilled runners use gravity to move forwards at great speed, and thus will shed light on how runners should condition themselves to run faster instead of wasting time on triple-extension drills.

This way to Part 3

References:

Feynman, R. P. (1963). The Meaning of it All. Strand, London: Penguin Books.

Mann, R.A., Moran, G.T. and Dougherty, S.E. (1986). Comparative electromyography of the lower extremity in jogging, running and sprinting. The American Journal of Sports Medicine. 14(6), 501-510.

McClay, I.S., Lake, M.J. and Cavanagh, P.R. (1990). Muscle activity in running. In P.R. Cavanagh (Ed.), Biomechanics of Distance Running (pp 165-186). Champaign, Illinois: Human Kinetics.

The Extensor Paradox – but not really Part 1 of 3

“How wonderful that we have met this paradox. Now we have some hope of making progress” (Niels Bohr, 1957)

A fundamental and ubiquitous belief among runners, biomechanists, strength and conditioning experts and running coaches is that a runner must push into the ground to propel themselves forwards. The faster a runner wishes to go, the more force they must push with. This belief is FALSE. It originates from:

  1. A failure to view observations in the context of evolutionary biology
  2. A failure to adopt a telelogical view of the function of muscle in locomotion
  3. Confusing cause and effect

This ‘push’ mindset is the basis of the obsession with so-called ‘triple-extension drills’ and coaching cues of driving the rear leg and slamming the foot into the ground.

This series of three posts will explain how the ‘paradox’ came to be and how, by viewing the existing evidence through appropriate filters, the ‘paradox’ ceases to be a paradox. A paradox in science really means that the current theory disagrees with experiments, which really means the theory is FALSE. If an alternative theory agrees with the same experiments, it is the one that should be believed while the old one has been falsified and should be binned (see earlier confirmation bias post). Claiming a ‘paradox’ is simply a reluctance to accept that the current theory has been falsified and to think about / consider alternative theories. As Niels Bohr said, a paradox is an opportunity to progress understanding. Sadly, as Thomas Kuhn recognized, scientists are human and are reluctant to give up their pet theory.

So what is the extensor paradox?

Studies recording electrical activity of muscles during running have consistently shown the extensor muscles of the stance leg (glute, quadriceps and calf) to be silent / switched off immediately after mid-stance. BUT, this is the very time when they ought to be highly active and forcefully extending the leg to push the runner forwards and up into the next flight phase, IF the theory that runners push back and down to go forwards and up is correct.

BTR-muscle-activation

The diagram illustrates activity in the leg muscles with the intensity of colour reflecting the extent of activation of the muscles. The third image from the left is mid-stance. Image four, when the runner should be ‘pushing’ clearly shows the quads and glutes to be completely inactive while calf activity is also decreasing.

At first glance, and with a ‘runners-push’ mindset, this appears to be impossible. Where is the propulsion coming from? After all, Newton’s third law states that for every action there is an equal and opposite reaction, so to go forward and upwards, there has to be push backwards and downwards, right? And it is the job of muscles to create the push, right? WRONG!

The next post on this topic will show why this belief is wrong and will use evidence that is cited to support the ‘runners-push’ mindset to show how this simply cannot be the case.

This way to Part 2

References:

Kuhn, T.S. (1962). The Structure of Scientific Revolutions. Chicago: Chicago University Press.

Mann, R.A., Moran, G.T. and Dougherty, S.E. (1986). Comparative electromyography of the lower extremity in jogging, running and sprinting. The American Journal of Sports Medicine. 14(6), 501-510.

McClay, I.S., Lake, M.J. and Cavanagh, P.R. (1990). Muscle activity in running. In P.R. Cavanagh (Ed.), Biomechanics of Distance Running (pp 165-186). Champaign, Illinois: Human Kinetics.

Weyand, P.G., Sternlight, D,B., Bellizzi, M.J. and Wright, S. (2000). Faster top running speeds are achieved with greater ground forces not more rapid leg movements. Journal of Applied Physiology, 89, 1991-1999.

BTR Training Zones

Bulletproof running entails good technique and training at the right intensity. The BTR method emphasises training at opposite ends of the intensity spectrum. Specifically, this means very short duration high-intensity exercise emphasising running-specific reactive ability, and long-duration low-intensity work to encourage mitochondrial-metabolic conditioning. Most runners experience the symptoms of ‘overtraining’ from prolonged activity in the metabolic-destruction zone. Exercise in this zone rapidly depletes energy stores, exhausts adaptive mechanisms and creates a systemic inflammatory response. Excursions into this metabolic minefield should be minimised and reserved only for competition and the final preparatory phase before the competitive season begins.

If you want to know more about the science and art of training and how to become a bulletproof runner, book your place HERE:

BTR-training-zones

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