"When it comes to the way your body utilizes fuel to create movement, there are two basic systems: aerobic & anaerobic. The first is typically referred to as “with oxygen” and can be thought of as the energy system used when you go for a 20min jog. The second is “without oxygen” and is the system that’s used when you do very high intensity efforts for only a few seconds to a couple of minutes - like a 100m sprint. There are more specific names for these systems depending on the time/intensity of exertion, but you get the point.
What I want to talk about today is how to train a desired energy system with two different goals in mind: increasing that system’s top end performance (power) and increasing that system’s ability to repeatedly do work with minimal fatigue (endurance). If you want to train your anaerobic system for power, your efforts need to be at near max and for very short bursts (measured in seconds), with long periods of rest so you can fully recover and hit each interval with the same, near max, effort. The focus is on the intensity of the output. The rest intervals often feel too long if you’re used to “getting your ass kicked” and ending the workout on the floor in a puddle of sweat. It’s okay - the rest is necessary to train for top end output. And if done correctly, you won’t be questioning whether or not you got a workout.
To train the anaerobic system for endurance, the efforts are at a slightly lower intensity (though still high) and should last a little bit longer (up to a few minutes). Since the intensity is lower, the rest/work ratio doesn’t need to be as high, but near full recovery is still the goal. We want each effort to be virtually the same, but we will accept a slight drop off. If a drastic decline in performance occurs from one effort to the next - let’s say the 6th set fell off - then we’ll call the workout there, or give an elongated rest before resuming.
For the aerobic system, the same rules apply. The major differences are that the time domains are longer, the intensity is lower and rest/work ratio is either one-to-one, or possibly even less rest than work if the intensity is low enough (thus, recovery doesn’t take as long). But a quick note on the time domains. Multiple sets of 10min of work at low/moderate intensity with a 2-10min rest in between is an aerobic workout. And it still is if we switch it to 5min of work with 3-5min rest. Or 1min work/1min rest. Or 30sec work/30sec rest. It’s about the intensity of the efforts(and also the total time). Because 30secs at an aerobic pace is a lower intensity than 30sec at an anaerobic pace, it only takes 30sec to recover to do it again. But a 30sec aerobic pace is different from a 10min aerobic pace. It’s all relative to the time domain, the rest period, and the aim of the workout.
To train aerobic power, you’re going to want shorter periods of work with one-to-one rest/work and more sets/reps (30sec on/30sec off for 10-30+min). To train aerobic endurance, you’ll be using longer periods of work with one-to-one (or less) rest/work and less sets/reps (10min on/2min off for 20-60+min).
The big take away is to consider - what is your intent? Do you want to train your anaerobic system or your aerobic system? Is your goal to improve that system’s top end performance at a specific time domain? Or is it to increase that system’s ability to repeatedly do work with minimal fatigue? Once we answer these questions, then we can approach our training more effectively.