Tag Archives: evolutionary biology

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The Secret to Speed- Symmetry

What makes fast runners so fast? Sure, strong muscles, hard work, and good technique all contribute to speed- but so does symmetrical knees?

The Proof

Scientists have recently discovered the surprising and remarkable effect symmetric knees have on running efficiency. Robert Trivers, an evolutionary biologist, took a team to Jamaica to investigate if there is any correlation between elite runners and their body symmetry. In one study, the researchers asked the club track and field members to give their best times in their specific running events, such as the 100m dash, 200m, 400m, or 800m. They found that in every single event group the fastest times belonged to the athletes with the most symmetric knees, not with the most muscle mass, lung capacity, or best technique.

Photo by David J. Phillip of Usain Bolt             Source: Oregon Live

 

To further confirm these results, they performed another study in which the research team measured the knee symmetry of 73 elite sprinters, including Olympic gold medalist Shelly-Ann Fraser-Pryce. They compared their measurements with those of 116 local non-runners who were of the same age and sizes as the elite athletes. They found that the sprinters had much more symmetrical knees than the non-runners, concluding that it is indeed a significant contributing factor to running efficiency. “Among the very best sprinters in the world, knee symmetry predicts who’s going to be the best of the best,” Trivers confirms after analyzing these results.

The following is a video of Trivers explaining his study and results.

Source: TEDxUWCCR

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But Why Knee Symmetry?

One reason why knee symmetry could be such a dominant factor in predicting speed is because running is naturally a symmetrical movement, and therefore it will favour symmetrical traits. By not having to compensate for non-symmetric mechanisms, sprinters with knee symmetry are able to save energy and be more efficient in every stride. In addition, numerous studies have confirmed that body symmetry is positively associated with genetic quality and developing advantageous traits, which may also contribute to the correlation between knee symmetry and speed.

What’s Next? 

This study has significant value as the results provide the basis for further research opportunities in the evolutionary biology and sports science fields. Evolutionary biologists may be interested in the genes that develop these symmetrical traits, questioning if they provide any other advantages to humans other than speed.  The track and field community and sports scientists may be curious to explore if there is any way to specifically increase knee symmetry through training in the hopes of it increasing speed significantly.

Furthermore, this finding has prompted more research into this topic and has led Trivers to address further questions, like are runners so symmetric because of good genes or because of the amount of exercise they do? Is it a cause or an effect? Nonetheless, there is a clear correlation between a high degree symmetry and being of the fastest humans. So, if you have symmetrical knees, you might very well be the next Usain Bolt.

By: Olivia Campbell