Episode 031 Understanding The Three Energy Systems

Episode 031: Understanding The Three Energy Systems

You need to understand the three energy systems at both level 2 and level 3 for your anatomy exam, and can expect 3-8 questions on this in your exam.

However, you DON’T just need this knowledge for EXAM DAY.

Not knowing the three energy systems has a cascade effect on your planning for clients.

If you cannot plan for clients effectively for the appropriate intensity then they won’t adapt physiologically as intended.

Which means you don’t get their goal

In today’s podcast episode 031, Neale and I talk all about the three energy systems and explain:

👉how this relates to PLANNING
👉creating effective CV sessions for your clients,
👉choosing the right intensity
👉and guaranteeing a result

Episode 031: Understanding The Three Energy System

Grab the FitPro Sessions Podcast show notes:


0:30 Introduction to Episode 031 of the FitPro Sessions Podcast
1:30 The importance of understanding the Energy systems
3:00 Testing someone’s Cardiovascular Fitness
4:00 Planning Cardiovascular training for Physiological adaptation
6:00 Energy system knowledge gives you a strategy for planning
8:00 What are the three energy systems – the 3 pans analogy
10:00 Deep dive into the three Energy System
15:30 How do energy systems relate to planning
17:30 The three intensity zones when planning CV sessions
28:30 what is meant by the term explosive?
29:30 Applying energy systems to planning for the client sessions
36:00 Leave a review and drop a comment
37:00 Reach out to us and join us in our Inner circle Facebook Group

Understanding The Three Energy Systems

1. What do energy systems DO?

We have three systems in our body and they each create ATP under different environmental conditions.

These three systems are:

  • Aerobic
  • Lactic Acid 
  • Creatine Phosphate System.

2. What are The Three energy systems?

These three energy systems are working all the time in our body to create ATP so that we can move, so we can live, so our organs can function, and that happens all the time for all three of them. 

However, when do specific exercises, with a specific demand on our body, as a result we will rely on one more than another.

Its kinda like 3 saucepans of water all simmering on a hob, and we turn up the heat more on the one we want to use most. Watch the quick video below to understand more

Creatine-Phosphate System: 

Let’s say for example we did something explosive, let’s say we are sprinting really hard or we are lifting something for just one repetition we would use our Creatine Phosphate system, which lasts for 10 seconds maximum.

Lactic Acid System: 

If we have this intermediate time, this is 10seconds all the way up to 3mins we would use our Lactic Acid System, so that could be a 400-meter run, it could be something whereby you are doing a set of resistance training for 12 reps, that’s probably in the 10 seconds to 3 mins which is lactic acid.


We spend most of our time Aerobic, I’m Aerobic now, Your probably Aerobic Listening to this. 

So, as a result, this Aerobic system gets used for anything that’s three minutes plus, and this is where we use it predominantly.

But just remember we are using all 3 all of the time.

3. How do energy systems relate to planning CV exercise?

CV exercise is done for a reason. We train using Cardiovascular sessions to physiologically adapt the muscles, heart, nervous and energy systems,.

Working in specific heart rate/intensity zones will create different adaptations on the body 

You need to choose the heart rate zone specific to the adaptation your client wants to achieve

Let’s start with the client goal and relate it back to energy system and intensity.

To make it simple we have divided it into THREE clear training zones, and labelled them as a traffic light system:

GREEN ZONE: for Endurance and Health Related goals as well as Beginners

These goals would all require the development of the Aerobic energy system and type 1 muscle fibres.

So the cardiovascular training session should target RPE 5-7 (out of 10) or 50-70% MHR  

GOLDEN ZONE: for hypertrophy and fat loss goals as well as achieving vo2 max improvements (fitness)

These goals would all require the development of the Lactic acid system (and high end of aerobic) as well as type 2a muscle fibres.

Therefore training between RPE 7 – 9 is most effective.

This is either side of the anaerobic threshold (at 8 RPE). 

Remember you cant spend longer than 3 mins in the anaerobic zone, so intervals would work best here

RED ZONE: for speed, power, explosive and absolute strength goals

These would all want to develop Creatine phosphate system and type 2b muscle fibres.

The most appropriate intensity would be between RPE 9-10, which is maximal effort or short periods (10 seconds) with longer recovery times. This is a positive interval

How to apply the THREE energy systems, when planning client sessions, 

  • start with their goal and ability 
  • know what physiological adaptation they want to achieve (
  • which heart rate zone/intensity is this 
  • then you can factor in long term progression of variables/ timing etc around this 

The Three Energy Systems Mock Questions:

Q1. Which energy system can burn fat as a fuel source?
A. Creatine-Phosphate
B. Aerobic
C. Lactic Acid System
D. Adenosine Triphosphate

Q2. Which sporting event would primarily use the lactic acid energy system?
A. 100m sprint
B. Ultra Marathon
C. 400m sprint
D. Javelin

Q3. Which intensity of Cardiovascular training would help develop type 2b muscle fibres?
A. Below RPE 8 (out of 10)
B. Between RPE 7 and 9
C. Between RPE 9 and 10
D. RPE 5

Download More Mock Questions like this:


Fitness Exam Mock Questions free download


Q1: B
Q2: C
Q3: C

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Hayley “understanding the energy systems” Bergman

Parallel Coaching

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