Anaerobic vs. Aerobic Training
Anaerobic/Aerobic Training in CrossFit
Your body has stores of a molecule called ATP (adenosine triphosphate). ATP is an energy molecule that allows you to do physical work like exercising. There are different ways that your body generates ATP for energy, and this is dependent on the duration and intensity of your workouts. Understanding the difference can go a long way in ensuring that you’re training properly and hitting your workouts with the right stimulus to get the gains you want!
What is anaerobic training?
Anaerobic training is your sprint workouts and heavy weight training. These types of workouts can last anywhere from 10 seconds to 90 seconds. All the energy produced in this time range is done WITHOUT using oxygen, which is where the term “anaerobic” comes from. You are working at such a high intensity that the demand for oxygen far exceeds what your body is able to supply. In the first 10 seconds of anaerobic training your body will break down creatine phosphate (CP) for energy, but your muscles have very small stores of this molecule, so it goes quick! Think of heavy power cleans or back squats. That shit is fun! After about 10 seconds your body will go into glycolysis where you’ll break down glucose (sugar) and will continue to do so until about the 90 second mark. Glycolysis is painful. Think of a 500m all out row sprint. That shit hurts. As you can imagine, anaerobic training is very demanding and taxing on the body and should be done strategically, just enough to get the benefits of it. Workouts lasting over 90 seconds will usually require the intensity to be pulled back enough to where sufficient oxygen can be supplied to keep producing energy. This is where we get into the aerobic system.
What is aerobic training?
Aerobic training is workouts ranging from a couple minutes up to a couple of hours. What defines aerobic training is you going at a low enough intensity to where the supply of oxygen is meeting the demands of the muscles to create energy. Your body can use this supply of oxygen to combine with glycogen (carbs) and fat to produce ATP. This of course varies with time domains. The majority of CrossFit style workouts rely HEAVILY on the aerobic system. I would say 99% of workouts are in the 5 to 20 minutes range and to sustain an output for that time range you have to stay aerobic. To clarify, just because you are going at a low enough intensity to supply oxygen for fuel does not mean that this style of training should feel easy. If you are looking to train and create adaptations for this system you have to push the intensity to the upper end of your threshold without getting into the anaerobic system, which is very uncomfortable. When your aerobic system improves, you are able to supply oxygen for energy at a much faster rate which allows you to go faster while staying aerobic.
How do I use these systems in training?
The amount of anaerobic or aerobic training you should do is completely dependent on what type of athlete you are. You will not get the optimal adaptations you want by training these systems simultaneously (in the same workout). If you are a low-power athlete, meaning you lack strength and power, you’ll benefit from more anaerobic training. If you’re a high-power athlete who can lift super heavy and sprint really fast, then you’ll benefit from more aerobic training. If you fall somewhere in the middle, then a balanced program is ideal. Makes sense, right?
Intervals are a phenomenal way to train both the anaerobic and aerobic systems. The important thing to understand when creating or doing these intervals is the work to rest ratio. If you’re doing anaerobic training your work should be short and your rest should be very long. A good example would be doing a 20-second bike sprint and then resting 3:00 before repeating it. This is a 1:9 work to rest ratio. This will allow you to go all out but give you enough rest to recover and put out close to the same intensity.
Anaerobic work/rest ratios – 1:5 – 1:12 (generally)
If you’re doing aerobic training, you’ll want your work and rest to be equal (1:1) OR your work is longer than your rest (2+:1). An example of 1:1 would be 3:00 on/3:00 off x 4 intervals. If you’re going more than 1:1 it could look like 4:00 on/2:00 off x 4 intervals which would be a 2:1 work/rest ratio. These are both aerobic but what changes is the intensity you’ll be able to go at. This is what makes intervals so great. Just by adjusting your amount of work and amount of rest you can create TONS of different stimulus. Aerobic intervals allow you to get a lot of volume and intensity into your training without beating your body down too badly. A good indication that you’re staying aerobic during these intervals is your ability to repeat your output and numbers from interval to interval.
Aerobic work/rest ratios – 1:1 – 2:1 (generally)
CrossFit test workouts, like what you see in the Open and other competitions, usually require both the aerobic and anaerobic systems. Understanding the difference in these systems and knowing which one you need to improve on will allow you to create a training program that is both highly effective and sustainable if planned appropriately! Next time you hit a metcon make sure you know the stimulus you want to achieve and the output you need to hold to stay in that energy pathway. When you’ve developed both of these systems, you will have the ability to CRUSH competition or test workouts that require you to be efficient in both systems.
