We can run longer than other animals

Among mammals, humans show exceptional distance running speeds. However, the amount of oxygen we need for running is insanely higher than in other mammals and running birds^1,2. To bypass this paradox, we developed outstanding heat dissipation capabilities, long Achilles tendons, big glutei, short toes and a myriad of evolutionistic precautions to better hunt down other animals in the open^1–3. Even though sporadic doubts aroused about the role of persistence hunting and scavenging in the evolution of human endurance running⁴, it is often suggested that we started running around 2 million years ago². Ça va sans dire, it is not very likely that we were wearing cushioned shoes at the time.

What if we ran without shoes?

The advent of modern running shoes would last an eye blink (around 200 milliseconds) if we shrank 2 million years in 24 hours. So it makes sense assuming that people, nowadays, would run in a similar pattern as their ancestors’ if asked to run barefoot⁵. When measuring runners of various experience levels, it is pretty clear that around 90% of people land on their heel while wearing shoes, whereas only around 50% of them would keep the same pattern after taking their shoes off⁶. While running barefoot, people tend to land on the ball of the foot, possibly due to the discomfort of striking the ground with the bare heel⁷. This is an indirect proof of how early humans ran.

What are foot strike patterns?

As you might already know from direct experience, your foot can strike the ground in several ways while running. Usually, we distinguish three main patterns, depending on which part of the foot touches the ground first. Here you can see a slow-motion video we took during one of our studies⁶ on foot strike patterns:

If you divide the foot into three equal parts, the first third would identify the rearfoot, the second the midfoot and the third the forefoot. For simplicity, I will abbreviate the rearfoot strike as RS and mid- and forefoot strike as MFS, joining the two into a unique pattern.

Rearfoot strike (A and B), forefoot strike (C and D) and midfoot strike (E and F). © Santuz et al., Ann. Biomed. Eng. 44 (2016).

Why do foot strike patterns matter?

Foot strike patterns matter because one does not simply change pattern by tuning the ankle angle at strike. On the contrary, foot strike patterns are the effect of many different variables’ adjustments, rather than the cause. In RS, the foot is more dorsiflexed than in MFS, while the knee is less flexed⁵, thus leading to the typical “seated” running form of RS runners. Moreover, in RS the knee is more compliant and the ankle is stiffer than in MFS⁸ and the collision impact, measured as loading rate, is higher than in MFS⁹. However, the ankle loading increases considerably when switching from RS to MFS¹⁰. Further, let us not forget that foot strike patterns, especially MFS, are a dynamical parameter, since they are strongly molded by fatigue¹¹.

Do we actually need to run barefoot?

It depends on what we want to achieve. Given the stunning amount of kinematic, kinetic and neurophysiological differences between foot strike patterns, taking our shoes off would add another degree of complexity to the new condition. Despite an evidence for leg and foot muscle growth after barefoot running training¹², the foot’s intrinsic muscle activity is higher when running in shoes¹³. This fact would point towards an unexpected increase in the neuromuscular output due to the presence of running shoes, meaning that the foot would not actually behave lazier, but would be simply activated differently. A less diplomatic but realistic answer could be, paraphrasing Prof. Jo Hamill: “what is the kind of injury you want to be exposed to?”^8,14,15.

Can we train to run barefoot?

Yes. With care, patience and perseverance. If muscles adapt quickly (let us say weeks as order of magnitude), tendons require longer periods (e.g. months). What most people do not know, is that bones can adapt as well, but the adaptation might require much more time than what tendons need.

Barefoot or minimalist running?

Despite the lack of a formal consensus on what a minimalist shoe actually is, there is evidence that minimalist footwear with low heel stack heights (e.g. 13 mm or lower) can accurately reproduce barefoot running in terms of kinematic and kinetic changes¹⁶. On the market, there are several minimalist footwear options. Just to give a few examples, Vivo Barefoot produces shoes in the most conventional way. Vibram thought to put fingers into normal shoes. LUNA Sandals had the idea, taken from the Tarahumara people, of eliminating any lining and upper and build a very simple sandal. Many other options are available and the market is undoubtedly rising¹⁶, thanks as well to social phenomena like the book “Born to run” by Christopher McDougall.

What is the heel-to-toe-drop?

In a shoe, the heel-to-toe drop, also called heel-drop, is nothing but the difference between the heel and the fore foot stack height. Please note that a drop of 0 mm does not imply low cushioning! A typical example is this: drop 0 mm and very low cushioning is your bare foot; drop 0 mm and a lot of cushioning is a shoe like the Altra Paradigm or the Altra Olympus. A detailed description on how to measure the heel drop can be found here.

Final considerations on barefoot running

Do it, do not overdo it. As a longtime track & field athlete, I strongly believe that we must keep busy with trying new things in order to maintain the motivation high. Barefoot or minimalist locomotion is an amazing way to better understand our own body and if done carefully and patiently, can bring more satisfaction than you can think of!

 References

1. Carrier, D. R. The Energetic Paradox of Human Running and Hominid Evolution. Curr. Anthropol. 25, 483 (1984).
2. Bramble, D. M. & Lieberman, D. E. Endurance running and the evolution of Homo. Nature 432, 345–52 (2004).
3. Lieberman, D. E., Bramble, D. M., Raichlen, D. A. & Shea, J. J. in Contributions from the Third Stony Brook Human Evolution Symposium and Workshop 77–92 (2009). doi:10.1007/978-1-4020-9980-9_8
4. Pickering, T. R. & Bunn, H. T. The endurance running hypothesis and hunting and scavenging in savanna-woodlands. J. Hum. Evol. 53, 434–438 (2007).
5. Lieberman, D. E. et al. Foot strike patterns and collision forces in habitually barefoot versus shod runners. Nature 463, 531–5 (2010).
6. Santuz, A., Ekizos, A. & Arampatzis, A. A Pressure Plate-Based Method for the Automatic Assessment of Foot Strike Patterns During Running. Ann. Biomed. Eng. 44, 1646–1655 (2016).
7. Santuz, A., Ekizos, A., Janshen, L., Baltzopoulos, V. & Arampatzis, A. The Influence of Footwear on the Modular Organization of Running. Front. Physiol. 8, 958 (2017).
8. Hamill, J., Gruber, A. H. & Derrick, T. R. Lower extremity joint stiffness characteristics during running with different footfall patterns. Eur. J. Sport Sci. 14, 130–136 (2014).
9. Boyer, E. R., Rooney, B. D. & Derrick, T. R. Rearfoot and midfoot or forefoot impacts in habitually shod runners. Med. Sci. Sport. Exerc. 46, 1384–91 (2014).
10. Rooney, B. D. & Derrick, T. R. Joint contact loading in forefoot and rearfoot strike patterns during running. J. Biomech. 46, 2201–2206 (2013).
11. Jewell, C., Boyer, K. A. & Hamill, J. Do footfall patterns in forefoot runners change over an exhaustive run? J. Sports Sci. 1–7 (2016). doi:10.1080/02640414.2016.1156726
12. Chen, T. L. W., Sze, L. K. Y., Davis, I. S. & Cheung, R. T. H. Effects of training in minimalist shoes on the intrinsic and extrinsic foot muscle volume. Clin. Biomech. 36, 8–13 (2016).
13. Kelly, L. A., Lichtwark, G. A., Farris, D. J. & Cresswell, A. Shoes alter the spring-like function of the human foot during running. J. R. Soc. Interface 13, 20160174 (2016).
14. Perkins, K. P., Hanney, W. J. & Rothschild, C. E. The Risks and Benefits of Running Barefoot or in Minimalist Shoes. Sports Health 6, 475–480 (2014).
15. Murphy, K., Curry, E. J. & Matzkin, E. G. Barefoot running: Does it prevent injuries? Sport. Med. 43, 1131–1138 (2013).
16. Squadrone, R., Rodano, R., Hamill, J. & Preatoni, E. Acute effect of different minimalist shoes on foot strike pattern and kinematics in rearfoot strikers during running. J. Sports Sci. 33, 1196–204 (2015).