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The importance of building an aerobic base for strength athletes

Training and fitness is a lifelong pursuit and evolution. Everyone has their own unique fitness journey and whilst this is absolutely amazing, what can often happen is that we get silo’ed into one of many aspects of ‘fitness’ and end up deep down the rabbit hole and drinking the preverbal fitness cool-aid of our chosen fitness domain.

For me, that was strength. 

Like many, I started my fitness journey in order to look better and appeal to the opposite sex. This was also rooted in a deep insecurity from being bullied at school and always being the little skinny kid who couldn’t defend himself. So alongside appealing to the other sex, there was a deeper need to be more ‘manly’. And that meant getting big and strong.

After a couple years of doing routines out of magazines and books, without too much structure to my training, (highlights included Cory Gregory’s 5 phase get swole programme) I stumbled across Stronglifts 5x5. I actually came across the Madcow version first and only after running that for 12 weeks did I do the original. 

Stronglifts, a brand name popularised by a guy called Mehdi is based on a training routine popularised in the 1960s by Reg Park (who was one of Arnold’s inspirations) and later adapted by Bill Starr, a competitive weightlifter and one of the first strength and conditioning coaches in the NFL who worked with the Baltimore Colts in the lead up to their first Super Bowl win in 1971.

And thus began a 10 year journey into strength and a whole load of drinking the strength athlete cool aid and buying into the myths that went along with it.

That’s not to say that this was bad. I’m still a HUGE advocate of strength and highly recommend the work by Mark Rippetoe (Starting Strength), Jim Wendler (5/3/1) as well as the late Louie Simmons of Westside Barbell and Greg Nuckols amongst many others.

The issue for me was that I bought into the whole ‘cardio will eradicate your gains’ mythology. It almost became part of my identity to be proud of being fit and strong and NOT doing cardio. I employed a lot of confirmation bias. Mainly to avoid doing boring old steady state cardio. Cause why run when you can lift?

’10 reps? No thanks, that’s cardio…’ (unless you’re doing GVT of course)

‘Cardio? Sorry, I don’t speak Spanish’

And when I talk about cardio, what I mean is long steady state. I didn’t approve of endurance athletes as they were all ‘too skinny’ and ‘don’t have any functional strength’.

I did over that decade do a mix of conditioning in various forms as well as play a variety of different sports such as Muay Thai, BJJ and Rugby to name a few of the higher intensity ones.

If any of this sounds familiar to you, then read on.

Here’s why you should build an aerobic base as a strength athlete and why it will not eradicate your gains (called the interference effect) but in fact improve your strength training.

Energy Systems

But first, let’s talk briefly about the 3 energy systems you use when training (an everyday life). 

Firstly, you’ve got the Phosphagen System / ATP-PC System. This system used phosphocreatine (PC) stored within the tissues of the body to generate instant energy at a high rate. This system doesn’t require oxygen, making it an anaerobic system but due to limited storage of PC in the cells, this system maxes out at around 10 seconds of all-out exertion. 

Think sprinters or Olympic weightlifters. Whilst the system maxes out after 10 seconds, it can be replenished in a few minutes which is why when you’re doing a strength workout, this will likely be your dominant energy system.

Then you’ve got the Glycolytic System / Anaerobic Lactic Energy System. This system can product ATP rapidly for use during activities that require longer bursts of energy from about 10-90 seconds max.

This system uses carbohydrates in the form of blood glucose and stored glycogen to produce ATP and like the Phosphagen system, does so anaerobically up to the 2-3 minute mark where the next system kicks in.

Think HIIT training or hypertrophy training.

Finally we’ve got the Oxidative System / Aerobic System (the topic of this article). This pathway does require oxygen (unlike the previous two) to produce ATP by using stored carbohydrates and fats. Because of the need for oxygen to work, this process is slower at producing energy, but can do so for very long duration (almost indefinitely). 

Think endurance athletes but also just long walks or the ability to maintain your core whilst standing up.

Ok, so that that we’ve done a quick overview of the three energy systems, let’s talk about why training your Aerobic System and indeed building an aerobic base is beneficial to both strength and hypertrophy training.

Interference effect

Firstly, before I get a lot of grief, the interference effect does exist and is real. Hickson first pioneered this work in the 1980s and reported that after a concurrent training intervention, resistance training-induced adaptations were lower compared to those that occurred when individuals perform only resistance training. What he was basically saying is that training endurance at the same time as hypertrophy inhibited the mTOR signalling pathway which basically got in the way of muscle growth. (putting it simplistically).


Without going too much into the science, a 2021 meta-analysis found that this can be mitigated by separating out the hypertrophy and/or strength sessions from the endurance sessions by at least 8 hours. 

Cardiovascular fitness

The aerobic system powers almost everything we do and is the energy system that can be improved the most. It also plays a strong role in events that are not thought of as being typically ‘aerobic’ such as the 200m sprint and mixed martial arts. It is vital for repeated high intensity efforts because it resets the anaerobic system. Basically, the fitter the aerobic system, the quicker it resets the anaerobic system. It’s the difference between gasping for air like a fish out of water between heavy sets in the squat rack or being ready to hit another set in moments. The anaerobic system gives you that quick burst of energy, the aerobic system determines how soon you’ll be able to access it again.

It forms a cornerstone of what the Soviets referred to as General Physical Preparedness (GPP). GPP is general training that improves your specific training by limiting your weaknesses, improving your quality of movement, and enhancing your body's ability to handle greater workloads.

 “The aerobic energy pathways are the limiting factor to anything we do” – Charlie Weingroff

This is where aerobic base building comes in. 

I’m not saying that you need to become an endurance athlete in order to supplement your strength training. But what I am advocating is taking time to build that aerobic base, and then once it’s built, you can simply maintain it. 

To quote Eric Cressey: “Athletes absolutely must have a well-developed aerobic system in order to recover both acutely (during the training session or competition/games) and chronically (between training sessions and competitions/games). It's relatively easy to improve if approached correctly, and can yield outstanding benefits on a number of physiological fronts.”

If you’re not convinced yet, then lets talk about the additional benefits of having an aerobic base and training your aerobic system will have on your metabolic health.

It increases the number and efficiency of mitochondria. More mitochondria help the body use more glucose and fat to make more ATP when your cells need it during exercise or other exertion creating a metabolic reserve.

Besides this you’ll see improvements in insulin sensitivity decreasing your risk of developing Type 2 diabetes and other cardiovascular diseases. It also reshapes your heart by increasing the thickness of the left ventricle allowing you to hold more blood. Furthermore it’s been shown to increase your VO2 max, often used as an indication of how fit your are.

Finally, doing an hour of slow steady state aerobic training does also burn calories which will help you with any fat loss goals you may have although of course this will be dependent on your total caloric intake and macro make-up.

How to do it - Implementation

It’s actually very simple. If you’ve never spent time building an aerobic base, you are in luck as you only really need to do it once and then you can maintain it. You can do it with a dedicated 12-16 week training block where you complete 2-3 aerobic training sessions per week on separate days from your strength training. 

A sample would be to alternate days between strength and aerobic meaning you train strength on Monday, Wednesday and Friday and do aerobic sessions on Tuesday, Thursday and Saturday. 

Whilst you can opt for most forms of aerobic exercise such as cycling, swimming, rowing, etc, the recommendation would be to run. The reason for this is because running provides specific muscular-endurance to the legs, core and other supporting structures. A bicycle displaces too much of your own weight and doesn’t provide enough of a stressor to provide the adaptation we’re looking for. It is too efficient. It is the same with swimming. The buoyancy offsets bodyweight. And being able to run is just a very human activity. Just ask Pheidippides whose running may well have saved the western world from Persian defeat.

The recommendation is to have the aerobic sessions be at least 30 minutes and ideally have one session last at least 60 minutes. The benchmark we’re trying to hit is a simple 10k run completed in under 60 minutes. Once you’ve done this, consider your base built. But that doesn’t mean you can complete cut aerobic training out. It’ll still have a valuable place in your training programme.

When building your aerobic base, your focus is naturally the building of your aerobic base whilst maintaining your strength. It’s not the time to do a muscle building hypertrophy phase nor the time to be trying to increase your 1RM. Do it in the off season.

Common mistakes

The most common mistake is actually going too fast. If we think back to the three energy systems from earlier, we are trying to stay in the aerobic system and during base building are best avoiding veering into anaerobic zones. To do this, you need to make sure you stay in what’s often referred to as zone 2. 

There are many ways to define what zone 2 means for you, but the easiest way to make sure you’re not going to fast is to monitor how you’re breathing. Ideally, all your aerobic base building training will be done whilst nasal breathing only. As soon as you start using your mouth to breathe, you’re going too fast or too hard and need to slow down until you can maintain nasal only breathing again.

This will feel very slow and for some could mean that you walk at points during the training, especially on hills. However you’ll find over the 12-16 week period that as you get fitter and the base gets built, you’ll naturally become faster. 

The biggest mistake you can make is have your ego take over and do all the training in zone 3 or higher and end up not building a base at all as you keep moving into the anaerobic energy system.


I won’t focus much on nutrition here and will cover it as part of a wider series on nutrition in the future. Needless to say, make sure you stick to a few key principles. Firstly, if you’re looking to maintain your muscle mass and strength, then make sure you are getting adequate amounts of protein in your diet. A rule of thumb for athletes is 2.2g per kg of bodyweight or 1g per lb of bodyweight. Besides that, adjust your total caloric intake accordingly. A base building phase is probably not the best time to go on a big fat loss calorie restricted diet. Make sure you’re getting enough fuel and focus on eating predominately whole nutrient rich foods as well as keeping up with your hydration. I’ll also throw in sleep here. If you’re training 6 times a week as I’ve outlined above, then you’ll need to be getting at least 7 but preferably 8+ hours of quality sleep each night. If you find yourself struggling with recovery, then it may be time to reduce overall training volume, assess your nutrition strategy and focus on quality sleep.


Strength is great and I highly recommend strength training to everyone. However neglecting your aerobic training means you’re leaving valuable health, longevity and fitness benefits on the table. It is possible to be both strong, muscular AND run. Running will not ‘eradicate your gains’ when performed in separate sessions and coupled with a sound strength and nutrition regimen with adequate protein intake. 

In keeping with the Viking theme of this blog, the true warrior will have the fitness to advance to battle and defeat the enemy.

“Conditioning is the application of fitness” – Joel Jamieson

Basically, you have to be fit enough to get to the problem. You have to be fit enough to resolve the problem when you get there.

Pure strength alone is pretty pointless if you’re unable to apply it and use it outside of the squat rack. What’s the point in having a giant squat if you’re out of breath walking up stairs, or get tired chasing after your kids. At that point it’s just ego.

If we think of modern warriors, tier 1 operators in the military come to mind. The US Naval Special Warfare Centre analysed the data from numerous selection candidates and came to the following conclusion: “Endurance (run & swim) is the most important factor regarding the probability of completing Hell Week.”

In both the UK Special Forces and the Royal Marines, Rucking/Tabbing for miles on end is part of the job. And again from the US Naval Special Warfare Centre, the data showed the following: “Rucking required a combination of strength and endurance… (but) running is the strongest predictor of ruck march performance.”

So I call on you, modern Viking Warrior, to have both strength and endurance. It is possible.

No more excuses.



Stuart is a level 3 qualified personal trainer and holds a nutrition coaching certificate from Precision Nutrition. He also holds additional coaching certifications from Clean Health, Steel Mace and Enlifted. Stuart has been training for almost 20 years and competes in Hyrox competitions as well as Golf. Stuart is also a currently serving in the military reserves.

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