Trying to understand what targeting specific energy systems means

When “targeting energy systems”, how is that done in the context of a week, 3 weeks, etc.

For example, a program might have something like VO Max Tuesday, Threshold Wednesday, Endurance Thursday, then a long ride on the weekend, or maybe a training race. Obviously each of those targets a different energy systems, so how do they work together?

Conversely I have also seen programs that would do something like nothing but endurance for a week, or, VO intervals. for 2-3 days.

Hi Tom,
Great question, and this is a big one! This may be a great option for us to pull into an upcoming Q&A session to dive in a little deeper.

This is getting into some of the theory of training and the various models you can use to create adaptations. What you’re describing is really two contrasting training theories. The first example would be considered more of a traditional approach where we attempt to improve multiple energy systems within the same cycle. Contrast that to the 2-3 day blocks of VO2 or endurance work and now we’re getting into what is commonly called Block Periodization.

Block Periodization has been around since at least the 80’s, and the goal is to target specific abilities in a small, concentrated “block”. To pull from a more specific definition, it would be considered “…a training cycle of highly concentrated specialized workloads.” The block is seen as "an autonomous compact unit of several elements combined for a specific function."

To your question of how they work together with the traditional approach, we have to keep in mind that this block approach was developed by elite/Olympic level coaches who were working within High Performance Programs that initially contained massive training volumes. As sport evolved, we saw an increase in the number of competitive days, and you can see now how continued focus on huge volumes of training would limit preparedness for athletes/sports that are looking at dramatically higher frequency of competition within a season. So this approach of concentrating workloads and making them highly specific was really to address the needs of these athletes and sport programs.

A mixed approach has been successful for most non-elite athletes. If we consider those examples of VO2 max, threshold, and endurance, those are all highly “aerobic” efforts. Maybe with shorter VO2 sessions or some sprints, etc. at the weekend training race, you’ll get a decent amount of anaerobic work, but overall your distribution will be heavily skewed to accomplishing aerobic work. So as we continue our consistent application of the exercise load on the body, we will see those improvements over time. Are there times when a block approach can help us? Absolutely, and it’s good to explore that. The caveat is that since you are now concentrating your training sessions, you have to provide the body with an equally “concentrated” amount of recovery following those days.

I hope that helps a bit. Definitely keep those questions going because this is a big topic and would do well as a Q&A session or webinar/podcast topic.
Coach Ryan


Thx Ryan, so when would be a good time or (how often ) to do some block periodization? I’m guessing an endurance block can be done anytime, again if given proper rest after. But what about say 2-3 days of VO work, or 2-3 days of neuro work?

Hi Tom,
Yes, so you can really do a block approach any time. I’ve used it sparingly with even some student athletes when they have something like finals coming up because it allows them to knock out a quick training block when they have the time and mental focus, and then chill out and allow themselves to focus that mental energy back on school. So it’s really quite open as to how often you can do it or finding a good time. It’s also a matter of choosing those high intensity sessions carefully. But aerobic stuff, you can do pretty much any time.

2-3 days of VO2 work can be very taxing on the body, and 2-3 days of neuro work I would actually not recommend. I would expect diminishing returns depending on how hard you are pushing, so finding the right effort is critical. I did a few blocks with a pro guy I was coaching a few years ago and we did 3-4 days of AM and PM VO2 workouts, but we were very specific in the power output he was holding. These weren’t all-out VO2 efforts. We had physiological data that helped to drive the specific powers to target, and we followed up training sessions with a lot of feedback and a POMS (Profile of Mood State) assessment to check on his mental energy. You need flexibility in blocks like that to understand when it’s time to bag it, and when you can push on. It certainly works, but it has to be done cautiously.

A simple way to explore it is to start with some lower level stuff like a VO2 session, followed by a threshold session for a 2 day block with 2 days of easy riding after. Or you might see something like 2x threshold sessions (think 6x8 minutes day 1 followed by 7x6 minutes on day 2) followed by 3x12 minutes in zone 3 on the 3rd day. I’ve also seen in many athletes preparing for stage races or MTB events where they will do some back to back threshold work or a couple big days, and then finish off with a large base ride because you can finish the overload and pretty much ride zone 2 even in a fatigued state. Keep in mind the recovery afterward and recover as hard as you ride on the block days.

Coach Ryan