Department of Paraclinical Sciences, University of Pretoria
+27828405194
info@myolab.co.za

Nature vs. Nurture

Introduction

How much do genetics contribute to the performance of athletes? Or can specific training increase performance for all humans? Are athletes born great or made great?

Scientists have been looking for that key gene for decades. But each time a new gene shows an association with some performance measure, the hypothesis gets thwarted by another (for more on genes and performance, refer to Tucker et al. 2013). However, there is no doubt that your genetic makeup does play a role. By merely looking at the different mammalian species, one sees a diversity of fast runners, runners that have endurance, or those with brut strength. Certain horse breeds are sprinters, some again known for their endurance ability. The same can be said about the various dog breeds – a grey hound vs. a bull dog. There is something inherent that brings these attributes to the forefront. Various models for exercise performance have been studied, from the Kenyan and Ethiopian runners, to those living at high altitude. 

However, very few animal species have been studied. From the approximately 5500 mammalian species out there (including us humans), less than 50 species have been studied on a skeletal muscle level. That is only 0.9% of the total mammalian kingdom! We must therefore study these remaining species as their muscles may reveal unique characteristics that have not been discovered before. These discoveries may bring us closer to better understand how skeletal muscle functions in humans and bring us closer to better understand exceptional sporting performance. The MyoLab is interested in both human and animal performance, especially between animal species and within human populations.

Current projects

Click on any project to read more about the topic, what we are doing and our findings (if available).




Project
Performance markers between animal species

Mother Nature has some pretty fast, strong and scary animals. Humans actually falls into the category of being the slowest and weakest. If we want to learn about performance, maybe we should study them… if they would allow us.

Species are formed as a result of small genetic differences. Mammals share a number of genes that are similar, with merely slight differences in their genetic code itself. Comparative, there are vast differences between land mammals on a morphological level. These include size, stature, muscle mass and limb length, to name a few. Muscle function of the various wild animal species are very poorly studied (only 0.9% of the 5500 mammal species have been studied on a muscular level.

The Myolab has already made some headway with regards to muscle contractility, metabolism and structure of some African wildlife species. For starters, the cat species (lion, caracal and cheetah) have more than 50% type IIX muscle fibres. Their prey, that includes the springbok, kudu, mountain reedbuck, blesbok and fallow deer also has more than 50% type IIX fibres. These fibres are very strong in comparison to the human equivalent.

In fact, the Myolab has shown that one type IIX single fibre from either the caracal or lion can produce three times the amount of power. To produce this exceptional power, these animals rely on efficient and an abundance of ATP generated from their muscle metabolism. Collectively, the cats and antelopes have a very high capacity to burn carbohydrate in the form of glycogen and blood glucose. However, this is where the prey has the advantage: they all have much more mitochondria in their muscle whereas the cats have very little.  In essence, the prey have speed and endurance whereas the cats only have speed. These findings confirm why cats need to stalk their prey and kill quickly. Once the antelope gets away and starts running, the odds of catching it becomes very poor.

What are we doing?

The Myolab has since collated all data on wild animals and is busy preparing a review manuscript for publication. Additionally, we are very fortunate to have a number of wildlife veterinarians forming part of this study and many species samples have since been collected. Thus, watch this space.


Project
Performance markers within human populations

“There is no doubt that our genetic makeup and our upbringing play a crucial role in what and who we are. But finding those little aspects… now that’s a different story…”

Although a very sensitive topic, science has observed that specific populations seem to perform better in sports than others. Kenyan and Ethiopian runners dominate the world of endurance running, whereas Jamaican and African-American runners dominate the short sprinting events. Others again dominate gymnastics, ball sports, to name a few. However, there are various internal and external factors that contribute to success.

There has been lots of speculation surrounding the performance advantage, like genetics or altitude, but thus far, no genetics can explain their success.

The human body can very easily and relatively quickly adapt to various forms of exercise, such as training loads and the environment (hot vs. cold environment, altitude). Thus, just because one group of people excels in a specific sport, does not necessarily mean that their success is genetic. Exposure to the sport, training volume and intensity, and motivation are factors that can significantly influence performance. However, to what extent these factors can push the human body to its limits and bring about the physiological adaptations, are still unclear.

What are we doing?

Together with some of the MyoLab’s collaborators, we are busy producing a review article that will focus on black and white sprinters and long distance runners. Many papers have focussed on the genetics, but this review will focus particular on observations and discoveries made on muscle physiology and the overall physiological response to exercise in a laboratory setting. Future studies will then be designed to answer the pressing questions that is still unclear.