Coach Mary’s Tasty tips #8
These next two weeks I will be talking about a new topic that goes very much hand in hand with the macronutrients we talked about last month. The new topic is energy systems; today I will introduce and explore the anaerobic systems, and next week I will tackle the aerobic system. This is a very long and extensive topic so I will make sure to apply and relate it to your day-to-day activities and workouts at the gym as much as possible to help you understand.
First things first, what do I mean exactly by energy systems? And what does anaerobic mean? The energy systems are the processes our body undergoes in order to convert the macronutrients we eat, such as carbohydrates and fats, into energy in the form of ATP. ATP (aka adenosine triphosphate) is a chemical molecule composed of 1 adenosine bound to 3 phosphates. All the energy produced and used by our bodies is in the form of ATP, so make sure you get familiar with this term because it is very important. In a simplistic matter, food is broken down by these energy systems in order to add the 3rd phosphate to this molecule, converting it from a low-energy into a high-energy state. When we need energy for either internal body functions or to do a workout at the gym, our body breaks down the bond between the 2nd and 3rd phosphate in the ATP molecule, supplying us with the energy we need. Anaerobic means that the ATP in these systems is produced under conditions that do not require oxygen (in contrast with aerobic, which require oxygen).
There are two different anaerobic systems: the creatine phosphate system and the glycolytic system. Even though they both operate under anaerobic conditions, they are very different from one another in the amount of energy they produce, the substrates they use, and their duration.
Starting with the creatine phosphate system, this is the very first one our body uses and it is the one used when we need energy to be produced quickly. This system converts creatine phosphate that is stored in our muscles into creatine and ATP (energy). This system produces energy in a very fast manner, but it also runs out quickly (only lasts up to 15 seconds), so it does not produce very much ATP in total. It is utilized before all the other systems, and once it runs out, the other systems take over to generate more energy for our activities. We rely heavily in this system when we participate in activities that require energy to be produced very quickly; these are high power activities such as performing a 1RM snatch, or a 10-15 second all-out sprint on the assault bike.
Once the creatine phosphate runs out, the body then starts utilizing glucose to produce more ATP anaerobically via the glycolytic system. The glucose comes from the glycogen stores we have available in the muscle and liver, or from the glucose circulating in our blood. This system produces more ATP than the creatine phosphate one, but it is still limited in the amount it can produce without oxygen. It usually lasts up to 1-2 minutes and produces most of the energy we need to complete short and intensive workouts such as Fran or Karen. Glycolysis uses a series of enzymes to convert glucose into pyruvate, but this is converted to a molecule called lactic acid when oxygen isn’t available. Lactic acid is what slows us down and prevents us from sustaining a high-intensity performance for longer than a few minutes; after that we have to switch to using the anaerobic system, which doesn’t allow us to maintain such high intensity of work. The longer you can sustain a high intensity the better your anaerobic capacity, and just like anything else, the more you train it the better you become at it.
As an example of how this relates to our daily activities, when we go to the gym and wonder how to approach a workout, we are all aware that we can only keep a 90-100% intensity for so long, and that we need to scale down to a slower pace if the workout is longer than 3-5 minutes. This is because we can only rely on our quick-producing anaerobic systems for so long before we have to resort to a slower, longer-lasting system. Now you can understand why the coaches constantly remind us at the board before a long workout to keep it at a 70% pace in order to keep a steady pace throughout the whole thing.
Lastly, I just want to point out how much these anaerobic systems depend on the availability of creatine phosphate and glycogen in the body. Glucose and glycogen stores are vital for the glycolytic system, so I want to emphasize the importance of eating carbohydrates on a regular basis and prior to doing short and intense workouts you aim to achieve an optimal performance. Just remember this the next time you show up at the gym without having eaten anything in the last 5 hours; your body won’t be ready to perform optimally at a high intensity without its main source of energy. So the next time you see a workout like Fran coming up, just make sure to stock up on those carbohydrates before coming in!
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