Sprinting and Science: A Paradigm Shift | by Frans Bosch

"Sprinting is a science." This was the maxim of Bud Winter. It's no coincidence that he carefully analyzed and studied the starting methods of Armin Hary, among others. In the past, Sam Mussabini also attempted to train 'scientifically' in his own way. Trainers like Carlo Vittori (Mennea) and Valentin Petrovski (Borzov) each applied scientific methods in their pursuit of better performance. Now, 50 to 60 years later, the picture paradoxically appears vaguer and less clear. Yes, sprinting is a science. But it's much more complex than one might have presumed. Frans Bosch, a globally recognized consultant and educator in sports, sheds light on the latest insights and developments.

In recent decades, many scientific fields, especially biological ones, have undergone a dramatic shift away from linear thinking. Instead of striving for a one-to-one connection of cause and effect, there's a focus on understanding 'emergence'; an organization stemming from the complexity of interconnected subsystems, where the appearance of that organization cannot be reduced to a limited part of those subsystems. In simpler terms, the behavior of the total system cannot be deduced from its underlying subsystems. The whole is no longer the sum of its parts, but the sum of the interactions of those parts, or even the interactions between the interactions, and so forth. With so many interactions and layers, causality loses its connection, yet a coherent organization can still emerge.

Linear processes, with their cause-and-effect connection, demand a blueprint. In a complex environment, such a blueprint must be adaptive, which inherently makes it fragile. A single flaw in the blueprint can be disastrous. Emergent phenomena don't face this problem. With interactions between interactions, they're not only flexible and adaptive but also robust.

A crucial condition for robustness is that a system or organism, like a rabbit in its burrow, isn't easily caught. In more complex terms, an organism is characterized by 'degeneracy,' where multiple components with different structures can fulfill similar functions. Thus, there are always multiple routes from impulse to execution. Therefore, from the impulse, there's divergence, spreading interactions over numerous simple processes, each governed by simple regulatory mechanisms, which aren't very precise. From these divergent processes and their interactions emerges a coherent whole, the emergent organization.

An athlete in full sprint embodies such a complex process of degeneracy and interactions between interactions. Various routes from the movement impulse to execution interact in such a way that no single one can determine the final outcome.

What does the sprinting organism aim to escape (to further extend the analogy with a rabbit)? Sprinting is a boundary load. The sprinter (and their coach) aim to push the limits of the muscle-skeletal system's capabilities and efficiently transmit maximum forces through the body. However, the body isn't naturally inclined towards this because pushing to the edge can easily lead to injury, from muscle tears to stress fractures. The evolutionary priority has been to avoid injury, especially in humans. Thus, strict performance-limiting mechanisms (escape routes) are built-in, which are more decisive for the final performance than performance-enhancing factors. For instance, the efferent pathways (those sending signals to the muscles) produce not only stimulating but also inhibitory signals, meaning an untrained individual might only engage about 75% of their muscle fibers in a specific movement pattern. Additionally, biotensegrity and co-contractions, necessary for controlling the body, also have inhibitory effects.

Especially in humans, the subsystems contributing to sprint performance tightly regulate each other through their interactions. Therefore, adding up the positive components contributing to performance at the individual level can overestimate the sprint speed of a top runner. Conversely, taking into account the (dampening) interactions and interactions between interactions (how the components limit each other's output) provides a more realistic estimation of the top speed achievable. Thus, the performance of a top sprinter isn't determined by the extremes of the fully operating components but by the inhibitory effect they exert on each other.

This inhibition makes searching for one or a limited number of underlying causes for performance ability a futile endeavor. These factor(s) won't be found. Fast-twitch fibers may indeed contract faster than slow-twitch fibers, but do they work better together with the elastic action of tendons? Slow-twitch fibers have better elastic capacity in their Z-lines (the connection between serially linked contracting sarcomeres), suggesting otherwise.

Moreover, do these tendons optimally function with the changing levers in the body (joints being complex structures where the axis of rotation often shifts during movement)? This interplay must then be synchronized with 'muscle gearing' (the angle at which muscle fibers work changes during contraction, giving muscles a sort of 'automatic gearbox'), which is influenced by (barely researched) muscle deformation. It's entirely unknown how these barely studied phenomena should be factored into an overall pattern like sprinting.

All of this must then align with a given body length and body proportion. This internal organization must, to zoom out further to the larger picture, adapt to constantly changing environmental conditions. Even then, we're not done. Environmental influences also affect the viscoelastic properties of passive tissues (the complex way tendons behave, for example), and we're back to where we started, or rather, we're back to a circle of interrelated factors. As there are cross-connections everywhere in this circle, it becomes more of a tangle of interrelated factors.

Inhibition

On top of these mechanical interactions comes the influence of inhibition (inhibition) by the brain based on afferent signals (signals resulting from mechanical interactions that the brain registers), or rather based on the subjective interpretation of these afferent signals (not the signals from the body, but what the brain makes of those signals). This interpretation by the brain is then influenced by socio-cultural factors. To make the Gordian knot even more complicated, genetic influences can be added, but then it must be epigenetic because gene expression is also influenced by environmental factors. That sounds like a complex interaction of interactions, but it's not even the tip of the iceberg. Physiological and hormonal processes, 'jerk' principles, and self-correction in 'spring-mass' systems (brief explanation), things that are reasonably understood through robotics today, haven't been mentioned yet and can further complicate matters.

Inhibition through interactions between components is thus decisive for performance. Those with the lowest thresholds of inhibition, not only having exclusively A-brand components in their system but also having the least inhibition built-in and a body that's simultaneously unstable enough to want to adapt to training stimuli (the so-called 'high responders') have a chance. In short, those who unite opposing demands of adaptability and robustness within themselves in such a way that they excel at a boundary load: sprinting at high speed.

The new direction in thinking about training will focus on reducing inhibition, moving away from increasing capabilities. This is a Gradwandelung (in German) elegantly visible everywhere in athletics: from Michael Johnson to Wayde van Niekerk, from Javier Sotomayor to Mutaz Barshim, etc. And as a provisional highlight of that change, Armand Duplantis; not the epitome of great capabilities, but the epitome of minimal inhibition.

Evolution and Outliers

The human anatomy is anatomically not suited for sprinting. There are numerous anatomical features that are nonsensical when it comes to top speed. For instance, the position of the foot relative to the thigh, at a 90-degree angle, results in inefficient energy transfer and limits maximum running speed. Distal muscle mass (mass far from the pelvis, such as in the calves) is cumbersome, a trait even understood better by chickens, turkeys, and especially ostriches than by humans. Humans are not born sprinters but born joggers; that they can do. Sprinting offers no evolutionary advantage because most predators and prey are faster over short distances than humans, hence the inefficient build for sprinting. Usain Bolt's top speed is a byproduct of characteristics that biologically aren't particularly useful. And perhaps the dominance of black athletes in sprinting can at least partly be explained by the fact that it is merely a byproduct.

Sprinting is dominated by black athletes. It might be interesting to compare sprinting with other movement patterns that stress the musculoskeletal system at the limits of its capacity. In activities like jumping, also evolutionarily irrelevant, the dominance of athletes of African origin is less pronounced (consider Jonathan Edwards, for instance, the world record holder in the triple jump), and this decreases as the approach speed decreases, from long jump to triple jump to high jump. This phenomenon cannot be explained solely by looking at a single performance determining parameter, such as the widespread idea that muscle fiber type (fast-twitch versus slow-twitch) is everything. Furthermore, pole vaulting, also an evolutionarily irrelevant explosive skill, is predominantly a 'white' affair.

In this context, it is interesting to look at a movement pattern that is evolutionarily relevant and also involves the limit load of forces. Throwing is evolutionarily essential. Being able to throw might have been as significant an evolutionary event as walking upright. Significant adaptations to the structure of the shoulder girdle were necessary to throw hard and accurately. There is no other species that can throw like humans. Look at throwing sports that stress the body to its limits. All ethnicities (white, black, Asian, etc.) produce roughly the same number of top performers in throwing sports (baseball, javelin throwing, etc.), depending on socio-cultural influences, of course.

It seems that differences in performance ability in high-speed running are somehow linked to its irrelevance. What then is so irrelevant about running at top speed? The decrease in the dominance of athletes of West African origin as running speed decreases gives an indication, which science is still far from fully understanding. Under time pressure (the support phase lasts less than 0.1 sec), maintaining a (albeit small) horizontal component in the propulsive force. In other words, at speed, there is increasingly less time to exert force backward against the ground shooting beneath the sprinter.

Where do you find individuals suitable for such a niche skill as sprinting? Probably where there is the greatest variation in the composition and interaction of organism components, and the chance mix that we recognize as a super talent is most likely to occur. There you find the 'outliers', the extremes, the physical freaks. Those athletes with such rigid tendons that they won't excel in ice skating or swimming, with a hormonal balance that shuts down all systems halfway up the Cauberg (known as a category 3-4 mountain climb in cycling), with lower legs so long that dribbling with a hockey ball will never work well, and with such muscle specialization that climbing a tree is almost impossible. But who happen to be able to bounce over a hard flat surface of synthetic rubber.

Do West Africans and their descendants in the Caribbean and the US harbor more of such 'outliers' than other regions? Perhaps, especially those who have a mix of properties that delay inhibition in high-speed running compared to others.

Finally

In addition to biological factors, there are, of course, many other factors at play, usually summarized in socio-cultural influences. To claim that these are more important than the biological factors, as Pitsiladis does, lacks any basis. He emphasizes socio-cultural factors that contribute positively to the performance of black athletes, while forgetting to consider the negative socio-cultural aspects. Sprint training already lacks much proper science; the expertise of coaches in the US, the Caribbean, and West Africa is also astonishingly low. The training some top athletes undergo is sometimes almost laughable, and the idea that they train so hard doesn't apply to many top athletes. Many top sprinters are notoriously lazy. Athletics is not the highly developed sport it claims to be, just like most sports bluff their professionalism. Moreover, the best coaches are found in a region (Scandinavia, Germany, Belgium, and also the Netherlands) where there is little talent available. They cannot afford to be careless with scarce talent and must make every effort to seek new avenues.

Athletics is the ultimate talent sport. Training too hard easily leads to injury or overtraining (jumpers and sprinters nowadays train much less than in the 1980s), and it is important to train as little as possible but just enough to hit the sweet spot of minimal inhibition.

From the perspective of minimal inhibition, it is more important to maintain and reuse the (elastic and kinetic) energy stored in the musculoskeletal system at speed per stride (not to 'leak' energy) than to generate extra energy (power). This is clearly visible in lightly built athletes like Lyles, De Grasse, Lemaitre, and Martina. Dafne Schippers is also an example of this, at least during the years when she was technically superior.

Degeneracy explains another phenomenon: there are multiple ways to shift inhibition. Hence, there can be such different body types at the start of a 100m final. Furthermore, there is another factor that may be even more important for the differences in physique among top sprinters. A 100-meter race is actually a sport consisting of two barely related sports, starting and accelerating, and running at top speed. For the start, it's useful to be small and compact; for top speed, length is an advantage. So, in a 100-meter race, we're not looking at a sport of pure speed but a mix of two somewhat opposing requirements. And could West African outliers be the athletes who best combine these opposing requirements within themselves?

It is also remarkable that the differences in body build among top endurance runners are much less pronounced. Perhaps this is because aptitude for endurance running did have an evolutionary advantage (see the theories and research of Daniel E. Lieberman). In East Africa, this aptitude has been better preserved than in other regions where humans migrated. Thus, the dominance of runners from that part of the world is based on a very different mechanism than the dominance in evolutionarily irrelevant sprinting. Conclusions from research into endurance running cannot be extrapolated to conclusions about sprinting.

Who knows, and science is still quite far from the answer. Perhaps it helps if we no longer ask why Usain Bolt can run so fast but start asking why Usain is less slow than the rest.

Recommended literature

Frans Bosch, Anatomy of Agility, 20/10 Publishers, 2019

Frans Bosch, Frans Bosch, Ronald Klomp, Running, Biomechanics and Exercise Physiology Practically Applied

Daniel E. Lieberman, The Story of the Human Body: Evolution, Health, and Disease, Atlas/Contact

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