This post was written by Dr. Shaun Owen, who is currently a Sport Scientist at BNZ Crusaders and Canterbury Rugby Football Union. He has a PhD in Sport Science, graduating with a cum laude in his Honors year. He has won the Super Rugby with the Crusaders in 2017, 2018 and 2019. He therefore brings much value in this article for both coaches and players alike.

The Adaptable Athlete

“It is not the strongest of the species that survives,
nor the most intelligent that survives,
it is the one that is the most adaptable to change.”


I often start with the above quote, which is commonly misquoted to Charles Darwin. Nonetheless, the principle is applicable in life and crucial to physical performance. The human body strives to maintain a constant state of balance, termed homeostasis, where it adapts to various physiological stressors in order to keep functioning. When it gets hot, we sweat; when our hydration levels are low, sensations of thirst are triggered etc. This is equally applicable to physical exercise. If an exercise stimulus or successive stimuli are too great and the body is under-prepared to respond, it might lead to sub-optimal performance and a higher propensity for injury.

This ability of the body to adapt under pressure is frequently termed physical robustness and resiliency—a goal for many practitioners when developing athletes. In a nutshell, it refers to the ability of an athlete to endure a physical load over a session, and then bounce back and endure those sessions repeatedly. Think of sportsmen completing a full week of training, competing in a match on the weekend and then repeating the process for 6 months. If the ‘what’ is to develop resiliency and robustness, the ‘how’ is building capacity in order to be adaptable.

In this case, capacity can be defined as the ability to physically perform. If we increase capacity, we advance those thresholds of resiliency and robustness. This has been shown repeatedly in recent studies, such as Gabbett’s work on Acute-Chronic Workload Ratios, comparing an athlete’s current capacity and workloads, and the resultant performance or injury rates. However, while the literature is relatively new in the world of sport science, the principle is not. A legend that most Strength and Conditioning coaches would know is that of Milo of Croton, the six-time Ancient Olympic Games champion. Legend has it that when Milo was just a boy, he would carry a calf on his shoulders and do a lap of the city every day. As the calf grew, so did his physical capacity, until he was a grown man carrying a fully grown bull. Taken with a grain of salt, the principle of the story stands, which is now known as progressive overload. This principle can be applied and expanded on with a few simple steps.

Step one: Identify the stressor

Initially we need to identify the stressor that we’re training for, the end goal, as well as the variation that might come with it. The idea is to build an athlete’s capacity to a point where they’re able to adapt and handle the stressor.

For example, in a rugby context we would start with reverse-engineering match-play, detailing position-specific demands of the game such as running distance, acceleration load, and sprint exposures.

Step two: Quantify your current capacity

The next step is to quantify your current capacity. This usually uses an average of your training exposure to the identified stressor over the last ~2–6 weeks, depending on the attenuation rates and context of the stressor.

In our rugby example, we might use GPS to quantify the average of the running distance, acceleration load, and sprint exposures a player has completed over the last 4 weeks.

Step three: Provide an appropriate stimulus 

The most challenging of the steps is designing a programme to take us from our current capacity to our target capacity. We need to decide what thresholds above or below our current capacity we’re willing to go to (often ~80–130%), as well as the time-frame to get there. A well dosed and periodised training stimulus that provides appropriate loading and recovery will result in positive adaptations. This where we can apply the principle of Milo of Croton. If we put a bull on the back of Milo when he was a child, he would’ve suffered injury. If we put a calf on the back of Milo when he was fully grown, he would have detrained. Simply put, load below or above capacity thresholds leads to maladaptation and potentially injury. Like most things, exercise can both be a medicine and a poison, entirely dependent on the dose. 

Overall, building capacity and loading appropriately relative to capacity is a fundamental for any physical exercise. We want to develop athletes that are adaptable to the stressors thrown at them, where the demands of competition are no different to those of training. In doing so, we’re providing athletes with a micro-dosed ‘vaccine’ to not only enhance performance, but to protect the body and set them up for successful long-term careers.

Wrap Up

I hope you enjoyed this awesome article by Dr. Shaun Owen. Next week we will follow up on this article and apply these methods to a few practical examples. Please feel free to comment on this article and let us know your thoughts.


We would like to take this opportunity to thank Dr. Shaun Owen for taking the time to write this article. It is an absolute honor to have you share your knowledge and experience with us. We hope to catch you on a podcast sometime and pick your brain on the subject matter that is Sport Science.