Energy Systems - 2018 November
So you’re looking at the Week Sheet to see what we’re going to do in practice and it says things like Aerobic Capacity and Anaerobic Capacity. But what does that MEAN?
Aerobic means “using oxygen”, anaerobic “not using oxygen”. Huh? Don’t we always breath oxygen? These terms refer not to the respiration of oxygen (breathing), but to the system your body is using to access stored energy for your muscles to use.
For short, intense bursts of movement like sprints we use an Anaerobic system. It’s a very quick way of accessing energy, and your body can convert the storage molecules into useable molecules easily…but it runs out quickly. Without getting into a lot of complicated biochemistry, the anaerobic energy systems are great for really intense activity of 30 seconds or less (explosive force), and for intense activity of up to about 3 minutes (anaerobic glycolysis), and neither use oxygen molecules. Anaerobic Capacity must be trained for, and trained hard. If you’ve ever missed a few practices, you’ve probably noticed that you don’t really lose all that much speed in a 25…but holy crackers do you start to feel it as you near the end of a 100, or a 200m race. During practice, think of things like “maximum sustained speed” and “max effort”.
Aerobic systems access stored energy by using oxygen molecules to convert stored energy molecules into useable energy molecules. (By the way, “stored energy molecules” come from food broken down during digestion) These are the systems we mostly use when exercising, for activities that last more than 3 or 4 minutes. To train for Aerobic Capacity, you need to sustain the activity for 20-40 minutes. These are those workouts where we aren’t so much sucking wind as it feels like our arms just might fall off.
Swimmers need to be able to use both the aerobic and anaerobic energy systems when competing. As a general rule, except maybe when you’re still a little guy or a beginner, 25’s, 50’s and 100’s are Anaerobic races, 800’s and 1500’s are Aerobic races, and 200’s and 400’s are Threshold races…where you push your body right to the threshold of switching energy systems and hope you get the balance right and you finish the race before your legs turn to lead.