In pursuit of the ‘Unbreakable’ Athlete: what is the role of moderating factors and circular causation?

The goal for sports medicine practitioners is to develop robust athletes, capable of withstanding high training and competition loads. For sports medicine professionals, understanding the workload–capacity relationship is central to achieving this goal. This editorial discusses how two different methodological frameworks—(1) moderation and (2) circular causation—align to develop physical capacity and injury resilience in athletes. The Arab proverb ‘ the straw that broke the camel’s back’ refers to a camel carrying a haystack that was so heavy a single piece of additional straw broke its back. In a sport setting, the ‘camel’ is the athlete, the ‘load of hay’ represents the maximal workload the athlete can tolerate safely (load capacity), and the ‘additional straw’ represents overload resulting in injury (capacity exceeded). The inherent biological qualities of the camel (eg, age, strength and so on) determine its cumulative straw -carrying capacity. Basketball superstar Kobe Bryant had strong training ethic, well-developed physical qualities and was largely injury-free in the early stages of his career. He was a strong ‘camel’ accustomed to carrying large loads with ease. We speculate that his athletic pursuits in childhood and adolescence contributed to his high load capacity in adulthood. Indeed, weight-bearing physical activity during childhood and early puberty has a positive, and possibly enduring effect on bone strength.1 Furthermore, after a certain age, the eccentric heart hypertrophic adaptation …