Lee Saxby's Wisdom of Coaching Blog

Intelligent Design

btr-horse-dog-humanLike most things in nature, the design of the human foot was an engineering solution based on the structural-and-organisational resources available at the time i.e. a primate, climbing foot.

Consequently, the human foot appears severely compromised when compared to the feet of other cursorial (running-specialist) mammals.

Devoid of hooves and pads, it is incredibly sensitive to changes in substrate and temperature and often lacks adequate traction.

For these reasons, most human cultures have attempted to protect and enhance the function of the foot with some form of footwear (fig. 1), from sandals (leather, reed, rice straw) to moccasins.

As human cultures ‘evolved’, footwear was no longer considered a purely functional tool but became one of the many status symbols of the social elite.

The most desirable shoes often being deliberately designed to be non-functional to confirm the elevated social position of the wearer from the hard, physical lives of the lower classes who laboured barefoot or in pragmatic-functional footwear.


The problem with ‘fashionable’ footwear (fig. 2) is that it is designed with little regard for the inherent plasticity of the human foot (it takes 18-21 years for the bones of the human foot to fully ossify) or for the biological law that ‘form follows function’.

Footwear design and technology may continue to change over time but the design and technology of the human foot will not.

BTR’s footwear manifesto can be found here, Anatomically-Intelligent Footwear and as Leonardo da Vinci said: “The human foot is a masterpiece of engineering and a work of art” – let’s keep it that way.


Hoffman, P. (1905). Conclusions drawn from a comparative study of the feet of barefooted and shoe-wearing peoples. The American Journal of Orthopedic Surgery, 3(2), 105-136.


“Nature does nothing in vain”


From the Greek telos, meaning “end,” and logos, meaning “reason”, teleology is the explanation of phenomena by reference to some purpose, goal, or function. For example, we could say the purpose of the eye is to see, and suggest that is why it developed. Scientists reject teleology as it can be used to imply an intelligent designer and pave the way for creationists who deny evolution by natural selection. Biologists argue that the eye allowing sight is purely a collection of random mutations, which conferred a survival advantage to the organism with it. However, this is also a teleological explanation as it assumes a purpose to natural selection in adapting an organism to its environment, thus improving its survival. As Nobel Laureate Albert Szent-Gyorgyi wrote “teleology resembles an attractive lady of doubtful repute whose company we cherish but in whose company we do not like to be seen”. Purpose provides the context without which many observations in nature make no sense. A teleological view is essential.

As a running coach, teleology provides a means to explain the injurious and inefficient movement patterns adopted by the majority of shod runners, such as the over-striding heel strike. Let us assume the purpose of locomotion (and the movement brain that controls it) is to get us from A to B with minimum energy and minimum risk of injury. Minimising energy is the first priority of the movement brain, derived from our hunter-gatherer origins in a calorie-scarce environment. As the cost of locomotion is paid per step (i.e. every time the bodyweight is supported against gravity), taking long strides makes sense because a given distance is covered in fewer strides and energy is saved. This pattern is characteristic of walking. The peak force of walking is low, so striding out and landing on the heel is not injurious. Long and fewer strides also save energy in running, but with higher speeds come higher peak force and injury. This is why habitually-barefoot runners have high step rates and do not overstride. A little more energy is expended, but injury is avoided. So why do shod runners do it? Cushioned shoes block the sensation of impact, but not the force. In the absence of this danger signal, the movement brain carries out its purpose and subconsciously produces the movement pattern that costs least energy.

Every movement results from the subconscious balancing act of primitive drives to save energy and avoid injury. This is the purpose of the movement brain. Understanding this is the key to coaching movement.




Szent-Gyorgyi, A. (1972). The Living State, with observations on cancer. New York: Academic Press

The hardware and software of running

Running is a skill, the skill of providing a stable base of support for an inherently unstable structure with a constantly moving centre of gravity. To improve this skill it is necessary to understand the relationship between:

  • postural stability (the neuromuscular system’s ability to stabilise everything above the talus bone) and
  • structural stability (the anatomical integrity of everything below the talus bone i.e. the human foot).

The lack of postural stability in a runner is predominantly a ‘software’ problem that can be rapidly improved with the right drills but structural stability is a ‘hardware’ problem, which requires time, gravity and the habitual use of anatomically intelligent footwear.


Correlation does not imply causation

“Statistics have shown that those who have the most birthdays live the longest” (Mark Twain)

The human brain has a tendency to draw causal links between events and to search for patterns between things where none actually exist. This is particularly the case where one event that follows another is believed to be the consequence of the first event. In the study of logic, this is described as post hoc ergo propter hoc (after this, therefore because of this).

There are many examples of this logical fallacy such as:

  1. When windmills spin quickly, more wind is observed; therefore, windmills cause wind
  2. Sleeping with your shoes on is strongly related to waking up with a headache; therefore, sleeping in shoes causes headaches

Example 1 is clearly false and is an example of reverse causality where it is the wind that causes the windmill to spin. Example 2 is an example of a ‘third variable’ problem where another factor unaccounted for gives rise to the apparent correlation. In this case, going to bed drunk explains both the shoe wearing and the morning headache. The third variable problem accounts for many false inferences of causation from correlation.

A topical running-related example is the association between foot-strike pattern and impact forces (implicated in overuse injury), leading to an obsession with forefoot striking. The ‘heel strike bad, forefoot good’ obsession has spawned running techniques such as Pose and even running shoes without heels along with a host of lower-limb and foot injuries. The apparent ‘causal’ link between heel strike and high collision forces has been drawn from one of Professor Dan Lieberman’s many landmark studies. However, it was never the actual conclusion. Other research from fellow Harvard scientist Irene Davis has shown similar impact spikes in forefoot runners. This is a classic example of a third variable problem. The third variable in this case is over striding. Using the physics filter, landing well in front of the centre of mass creates a large braking force angled back at the runner (Newton’s third law of equal and opposite action) regardless of landing pattern, though the evolutionary biology of the ankle joint means a heel strike is more likely especially when cushioned-heel running shoes block the discomfort that triggers avoidance of heel striking seen in barefoot runners on hard surfaces.

Causality can only be established by satisfying certain criteria in the design of the experiment. Correlation / observational studies do not satisfy these criteria. Causality claimed from correlations should always be viewed with suspicion.


Beebee, H., Hitchcock, C. and Menzies, P (eds). (2009). The Oxford Handbook of Causation. Oxford, UK: Oxford University Press.

Lieberman, D.E., et al. (2010). Foot strike patterns and collision forces in habitually barefoot versus shod runners. Nature, 463 (7280), 531-535.

Willy, R.W and Davis, I.S. (2014). Kinematic and kinetic comparison of running in standard and minimalist shoes. Medicine and Science in Sports and Exercise, 46(2), 318-323.

For more Science of Running wisdom, become BTR certified and get full access to the BTR Coaches Network and the BTR Coaches Toolkit. Details of our BTR Education Pathway can be found here.

The Running Dialectic


The epidemic of chronic running injuries is still plaguing humanity. Since 2010 the running community, disillusioned with the ‘scientific solutions’ offered by ‘modern shoe technology’ began to remove their shoes in an attempt to embrace mother nature and her panacea for all running related problems; barefoot running. Five years later runners have come to realise that mother nature is a cruel mistress, as she removes knee pain with one hand, she delivers ankle and foot pain with the other. Her message is loud and clear; she will make no allowances for lack of skill.

The BTR education system has been created with the intention of becoming the internationally recognised, ‘gold standard’ educational program for running technique, performance enhancement and injury prevention. All BTR certified coaches have demonstrated a solid understanding of movement science and more importantly a level of coaching skill expected of a professional coach. The BTR coaching certification system has raised the bar in terms of practical coaching ability to a level that only a few will achieve.

Confirmation bias in science

“…if the only tool you have is a hammer, everything begins to look like a nail” (Maslow, 1969)

Confirmation bias is the tendency to search for, interpret, or recall information in a way that confirms one’s beliefs or hypotheses (wikipedia).

The History of science is replete with examples of confirmation bias. The earth was thought to be flat for thousands of years until sailors not falling off the edge and the advent of astronomy showed the theory to be false. Philosophers of antiquity thought the Sun revolved around the earth (Geocentricism) until Galileo’s telescope showed the theory was false and the opposite true (Heliocentrism).

The process of showing and attempting to show theories to be false by experiment was invented by philosopher Sir Karl Popper and is detailed in his landmark text ‘The Logic of Scientific Discovery’. It is the cornerstone of good science. If theory and experiment disagree, the theory is falsified; if theory and experiment agree, the theory survives. Theories that have survived years of experiment without falsification are called laws. Examples include the laws of physics, the laws of chemistry and the biological laws of evolution through natural selection and Wolfe’s law that form follows function.

Laws act as trustworthy filters through which information and new theories can be judged. If theories violate natural laws, they are false.

natural laws

Modern running-related examples of confirmation bias include the belief that cushioned, structured shoes are necessary for running; that running injuries can be treated with yoga-type stretching; and that high-intensity-intermittent exercise like Cross Fit is the best way to health and fitness for humans.

  • Physics and evolutionary biology show the shoe theory to be false. The forces of running do not simply go away and we know that natural selection shaped the human body to specialise at distance running without added equipment.
  • The theory that stretching helps running injury is also falsified by both the physics and evolutionary biology laws. Stretching alters the stiffness of tissues affecting their ability to withstand and control forces. Evolution selected soft-tissue properties that stabilised joints (ligaments) and stored elastic energy (tendons), stretching adversely affects both properties.
  • The recent suggestion that high-intensity-intermittent exercise is the best way to achieve health and fitness is falsified by fundamental principles of biological chemistry and evolutionary biology. Humans are endurance (aerobic) animals that evolved in a calorie-deficient environment with low-level but prolonged daily activity. Anaerobic metabolism is inefficient, quickly depletes energy stores, produces damaging and inflammatory by-products and is a mismatch with our evolutionary heritage.

Stick to the laws

In the sea of information of confirmation bias, trust only that which agrees with the fundamental laws of physics, chemistry and evolutionary biology. By the most rigorous application of science, they have never been falsified so are the only principles we can trust.


Maslow, A (1969). The Psychology of Science: A Reconnaissance. Boston: Gateway

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

The Human Sea Squirt

Juvenile sea squirts move around a lot and have a rudimentary brain. As they approach adulthood, they attach themselves to rock, stop moving and begin to digest this rudimentary but metabolically expensive organ whilst developing a large gut. Sound familiar?



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