The Energy Systems – Ep. 1

In the past episodes, we have taken a close look into programming at CrossFit AKA. In the next episodes, we will have a look at how our body actually performs these workouts. We will start with an introduction of the main energy systems that drive all human performance. To perform any sort of movement, we need muscular contractions. However, these muscular contractions are not free of charge. We pay for muscular contractions with energy, which is stored in a little molecule called ATP, or Adenosine Triphosphate.

In muscle cells, ATP splits into ADP + P + Energy (Adenosine Diphosphate + Phosphate + Energy), which can drive these contractions. In other words, the currency for energy and therefore muscular contraction is ATP (in a later episode, we will take a closer look into the mechanisms that drive the muscular contraction). Our body has enough ATP stored in muscles to produce maximal muscular effort for about 1 to 2 seconds. But when the ATP-tank is empty, we got ourselves a situation. Our muscles cannot obtain ATP from the bloodstream, on the contrary: our muscles need to rebuild ATP – and they do so with the help of three different systems on which we have already touched in prior episodes: they are the phosphagen (or phosphocreatine or CP) pathway, the glycolytic (or anaerobic glycolytic) pathway and the oxidative (or aerobic glycolytic) pathway. In the picture, you can also find the the aerobic lipolysis pathway, but as this pathway is low on power and associated with activities of extremely long durations, it is that relevant for a CrossFit workout. All three pathways have their specific time domain (x-axis) and power output (y-axis). As displayed in the picture, the use of the readily available ATP followed by the addition of the phosphocreatine provides the most power, but can only be maintained for a really short period of time. The anaerobic glycolytic pathway can hold up a bit longer, but has a significantly lower power output. Finally, the aerobic glycolytic pathway can last up to hours, but again, power output diminishes.In the next episode, we will dive further into each pathway. We will show how these pathways produce ATP, how they interact with each other and how they affect your workout.

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