Hybrid Training: Strength & General Aerobic Development
Strength training and aerobic training can, in many ways, be seen as opposite of one another.
As a result, the combination of them can make a confusing thing to get right.
However, if you put some thought into the programming, it is more than possible.
In fact, their combination will likely bring you far better results long-term than doing either alone.
So, what this article will cover is the following:
What do we mean by ‘strength’ or aerobic fitness?’
Is the interference effect real?
Strength training volume & intensity
Strength training frequency
Time-saving strategies for strength training
Aerobic training volume & intensity
Aerobic training exercise selection
Separation of intense training
Sample week
What do we mean by ‘strength’ and ‘aerobic fitness?’
As always, let’s get our definitions straight before moving on.
What is meant by strength training is likely more intuitive for you.
Here, we are referring to it as the maximal load that can be moved.
Strength is typically specific to a movement pattern, but this article will take a more general strength development approach.
The point of difference that I’d like to make here is that, in this article, you should assume that training for strength & training for muscle growth are synonymous. For the most part, there really is little difference between the two anyways.
I will soon publish an article & video explaining this in more detail. If that would interest you, make sure you’re subscribed to the newsletter to be updated as to when it comes out.
The means through which strength will improve can be stated quite simply: you will increase the size of the contractile units within your muscle.
In other words: you life heavy circles, your muscles get bigger.
Strength training does have a number of ancillary adaptations, including increased strength & integrity of your body’s connective tissue (tendons, ligaments, bone, etc.).
What it means to train your aerobic system might be a little less intuitive.
There are two general means of producing energy your body has access to: aerobic and anaerobic.
The term “aerobic” means ‘relating to, involving, or requiring free oxygen.’
Your aerobic energy systems can produce far more energy and last far longer than your anaerobic energy systems.
As a result, your body’s ability to take oxygen out of the air, get it into the working muscles, and use it for energy production is the limiting factor for a wide variety of things within fitness.
This is true whether you are talking about middle to long distance running, or if you are talking about recovery in between sets or sessions of strength training.
There are four main limiting points to this use of oxygen, and therefore four main points of improvement. These include:
Stroke volume
This is how much blood your heart pumps with every heart beat
As your aerobic fitness improves, your blood is able to pump more blood with each heart beat
Muscle capillary density
These are the exit ramps from your main blood supply into your muscles
The more of these exit ramps there are, the easier it is for blood (and therefore oxygen) to get into your muscles
As your aerobic fitness improves, the density of these capillaries in your muscles increases
Mitochondrial density
Mitochondria are called the ‘powerhouse of the cell’ because they are were aerobic energy production occurs
The more mitochondria there are in your cell, the more room there is for aerobic energy production
As your aerobic fitness improves, the amount & density of mitochondria in your muscles increases
Lipolytic (fat burning) enzyme production
fats can only be turned into energy aerobically (carbs can be burned aerobically or anaerobically)
The more of these fat burning enzymes you have, the easier it is for your body to use fats for fuel
As your aerobic fitness improves, the amount of lipolytic enzymes your body produces increases
The 1st & 4th points on that list happen systemically (whole body), while the 2nd & 3rd only occur in the limbs doing the work.
The significance of this will be discussed later on.
Maximal strength can be assessed by looking at muscle size or by looking at your 1 repetition maximum on a given lift. You can use 2RMs or 3RMs to assess strength too, it’s just that 1RMs are more commonly used.
Maximal aerobic fitness can be assessed by looking at VO2max; the maximal volume of oxygen your body can use for work.
It is defined by milliliters of oxygen used per kilogram body mass per minute (ml/kg/min).
Both of these are gross simplifications of what happens to your body when you perform strength or aerobic training.
However, I thought that providing these backgrounds would put the remainder of this article into better context, and make it clearer what it is we seek to train.
The interference effect: is it real?
Short answer: no.
Slightly longer answer: maybe, if you want to win the Olympia or break the IronMan world record.
I cover this extensively here.
Strength training volume & intensity
The resistance training portion of the program pertains to modalities including strength training, hypertrophy training, and power training.
These can be further broken down into weight training, calisthenics, plyometrics, olympic lifting, ballistics, etc.
In essence, this section pertains to any movement in which the mechanical capability of the musculoskeletal system is the limiting factor.
With this portion of the programming, there are two variables you should think about first: volume & intensity.
First, let’s define volume.
Most practically, volume is defined by the number of number of sets taken ~1-3 reps shy of failure per week. This means of defining volume can be applied on a per muscle basis; ie # of sets / muscle / week.
Historically, you may see volume defined as # * reps * weight. For example, 10 sets of 10 squats with 10 pounds would equal 1000 pounds of volume. However, there’s a problem with this.
Recent research has shown that:
Getting within ~1-3 reps of being unable to do any more reps (failure) results in maximal benefit from the set. [6]
If a set is taken this close to failure, it does not seem to matter if the set was 6 reps or 16 reps in duration. [14]
In other words, if you did 6 reps and could have done 8, then you will get the same results as if you did 16 reps and could have done 18.
For the most part, we have also covered intensity as the other variable in this equation: getting within 1-3 reps shy of failure.
So, that said, how much volume should you do?
The general consensus of the research is that the more the better, provided you can recover from it. [7,15]
That said, there are important points to keep in mind when it comes to what you can recover from, including:
Current fitness level
The higher your aerobic fitness, the more likely you can handle higher volumes with good recovery. [3,4]
Similarly, the higher your current strength is, the more you can likely tolerate.
Sleep hygiene
The better your sleep, the more you’ll be able to handle.
Stress from life, work, relationships, etc.
This may ebb and flow more than the others, but stress is stress. The more stressed you are at any point in time, the less volume you can likely handle.
The point of me saying all this is to say that there are a lot of variables that influence what’s best for you.
Some evidence has suggested that the lowest possible amount of strength training you can do and still see some progress is likely ~2-3 sets per week. [16] Here’s how to use this information:
Start your programming off with 4-5 sets / muscle group / week; perform this volume for ~2-3 weeks.
Monitor how you feel and how you are performing.
Over time, slowly build the volume that you perform.
At a point, you will notice you will either 1) stop making more progress despite doing more work or 2) feel noticeably more fatigued (either day to day or in your training).
Once you hit this point, the optimal volume for you is usually ~2 sets less per muscle group per week.
Strength training frequency
Frequency just refers to how you split up the volume of your strength training throughout the week.
For instance, say you intend to perform 6 sets of chest per week. Your choices of frequency may be:
performing 6 sets 1x/week
performing 3 sets 2x/week
performing 2 sets 3x/week
There does seem to be some benefit to training a muscle 2 or 3 times per week as compared to 1 time per week, but it is a small and often unnoticeable difference. [17]
However, higher frequency training (2 or 3x/week instead of 1x/week) is still something that I would recommend to everyone- particularly someone following a hybrid program as is being outlined in this article.
The reason being is increased flexibility with your program if life happens.
For instance, say your program calls for all of your chest volume to be done in a single session.
Say something comes up (and something will come up at some point) and you need to miss this session.
You will have lost 100% of your weekly volume for your chest.
If this volume was split up into 2-3 sessions, then missing one would be no big deal.
The other sessions will likely still be sufficient volume for you to see progress, and you can just continue on with the rest of the program as normal.
The same would be true for any strength attribute, by the way, not just your chest.
What this means in practice is that it is not the best idea to follow a “bro split” (train one muscle at a time) or even a “push, pull, legs split” in my opinion.
Rather, I would encourage you to use either full-body workouts or an upper body / lower body split; as these tend to blend much better in hybrid programs.
Time-saving strategies for strength training
I find strategies such as these to be important for hybrid training of any sort, as ~half of your training will be spent focused on variables other than strength/hypertrophy themselves.
There are two in particular I’d like to highlight.
First: antagonist-agonist supersets
Basically, this refers to alternating between to exercises that have no overlapping muscles; as opposed to doing straight sets of a single exercise.
The idea is that you generally need ~3:00 of rest between sets of the same movement in order to pump out quality sets; otherwise the fatigue of too little rest limits you.
Well, using supersets of this sort, while one set of muscles are working, the others are resting.
So, instead of resting 3:00 between sets, you can rest ~1:00-1:30 between sets.
A 2023 study [12] found that subjects using this strategy achieved the same results as those using straight sets in nearly half the time.
The key here is to use exercises that do not have overlapping muscles.
Squats and deadlifts would not work because they both train the back and glutes.
Reverse lunges and leg curls would work, though.
To be clear, this doesn’t NEED to be done with movements that are direct opposites of one another.
For instance, a leg press and a dumbbell lateral raise have nothing to do with one another. So, this can also make an effective & convenient superset.
Second: drop sets
A drop set is likely not a new term to you if you’ve been around the block long enough.
This refers to performing a set to failure, dropping the load by ~30% or so, and then immediately continuing on with more reps.
failure = the point at which you cannot do any more reps
The idea is that the last couple reps before failure are a bit more stimulating for muscle growth, and a drop set helps you stay at this intensity of reps longer.
This can be done by simply using less weight, or it can be done by modifying the exercise. An example would be dropping into knee push-ups after doing as many standard push-ups as possible.
Another 2023 study [13] found that subjects using such a strategy were able to achieve the same results as those using straight sets in ~1/3 of the time.
Aerobic Training Volume & Intensity
There are two distinct kinds of aerobic training required for this portion of the program.
First: higher-volume, lower-intensity training.
Second: lower-volume, higher-intensity training.
Both are equally as important as the other. Many of the adaptations from them overlap, but some are unique to one or the other. [19]
The definition of volume of aerobic training can take many different forms depending on what modality (rowing, running, etc.) you are using for your aerobic training.
The most practical definition of volume for the purposes of general aerobic development, though, is to simply use the total duration of training time (in minutes).
This will be true whether you are talking about 4 minutes at max effort or 60 minutes are a low effort.
Intensity, also, can be defined in many ways.
The most common & practical ways are by using your heart rate or simply with your perceived level of effort.
To use heart rate to guide intensity would require you to know what your maximum heart rate is.
The simplest way to figure this out is to subtract your age from 220 (220 - your age = max HR). Using this means to estimate your maximum heart rate is not perfect, and can potentially be +/- 10 bpm off of your true maximum heart rate.
I will soon be publishing a guide on how to perform a max HR test. If you’d like to be updated as to when that comes out, consider joining the newsletter here.
Once you have identified your maximum heart rate, you will use percentages of that number to guide your training.
For these purposes, we’ll define low intensity as 60-75% max HR and high intensity as 80-95% max HR.
As we are defining it, you may see “low intensity training” and zone 2 training as synonymous.
If you do not have a heart rate monitor, paying attention to your subjective perception of effort can make a more practical, and just as good, way to track intensity.
For these purposes, we’ll define low intensity as an effort level where you could sustain a 20-word sentence without gasping for air (4-6/10).
We’ll define a high intensity as an effort level in which you could not sustain a 10-word sentence without gasping for air (7-10/10).
Low intensity training
Regarding the low-intensity & high-volume training, it is difficult to give specific recommendations on how much volume you should do.
For the most part, the higher the volume (i.e. the higher the total weekly duration) that you can commit to and regularly perform, the more benefit you are likely to get.
This is not to say that you should jump right into the highest volume that your schedule will allow, but building to that will bring you the best results.
That said, here is a good general guideline if you are new to aerobic training:
Start out with 60 minutes total per week.
From there, add 10 minutes to your weekly training volume each week.
A good goal for most people to aim for is to build to 2 hours (120 minutes) per week and maintain that long term. This dose will be sufficient to have most people covered, as far as low heart rate training goes.
Again, though, if your schedule allows for more, then pushing past this may be better.
High intensity training
The other side of your aerobic coin is high-intensity training; which should be the polar opposite than what was just described.
This is something you would only do 1x/week, and should be drastically shorter in duration.
The caveat is that it needs to be long enough for your aerobic, not anaerobic, energy systems to be the limiting factor.
Two examples of this could be as follows:
20 minutes @ max effort (80-95% max HR)
Intervals, such as:
2 minutes @ 5/10 effort
4 minutes @ 9/10 effort
repeat 3-4x
Aerobic Training Exercise Selection
There are many different ways you can do cardio, and being strategic with which modality you choose can be to your advantage.
When your goal is to develop your aerobic fitness at large, one of the first things worth considering is making sure your whole body is receiving the stimulus to adapt.
Some of the adaptations derived from aerobic training are systemic (meaning across your whole body), while others are site-specific (meaning they only occur in the limbs performing the work).
Most modalities of aerobic training involve your lower body; such as running or cycling. Basically, what I am saying is you should try to have some sort of upper body aerobic stimulus as well.
Two modalities of aerobic training that will cover both upper and lower body simultaneously include an AirDyne or a rower.
Two modalities that will be more specific to the upper body include swimming and a SkiErg.
Two modalities that will be more specific to the lower body include cycling & running, as mentioned before.
Some of these tend to be more fatiguing than others. There are three main factors that will make one more fatiguing than another, including:
Impact
Eccentric loading
Eccentric = the lengthening of a muscle. In other words the descent of a squat is the eccentric portion, the ascent of a squat is the concentric portion.
Large ranges of motion
Range of motion refers to how far a joint is moving around its axis.
For instance, running has a small degree of eccentric loading and, obviously, involves impact. This is why it tends to be perceived as more fatiguing than cycling even if the same duration of work is done at the same relative intensity.
The bottom line is that having a thought-out combination of different aerobic training modalities can be to your benefit.
This is true in regard to maximizing your aerobic fitness as well as blending this with strength training.
Separation of Intense Training
The #1 most important thing to get right in any concurrent or hybrid program is proper fatigue, recovery, and load management.
Getting this wrong is the most common cause of someone failing at this endeavor, in my opinion.
As you may guess, high intensity training is more fatiguing than low intensity and requires greater recovery time.
High intensity training, as I am using the term, may refer to heavy squats, plyometrics, olympic lifts, or threshold running.
In general, it is best to give a muscle or muscle group at least ~48 hours of time between intense trainings. This of course varies on the program overall.
What does this mean?
Let’s say you have heavy squats on Tuesday.
You could do an easy run on Monday or Wednesday, but you probably shouldn’t do a threshold or HIIT run on either of those days.
Sample weeks
To wrap up this article, I wanted to provide you with some sample weeks of training so that you can see what this might look like from a bird’s eye view.
I will leave out the minute details that go into constructing each session, as much of that has already been covered.
However, if you want to see what this would look like with all the details put to use, then consider joining our newsletter: Fitness Simplified Fridays. When you do, you’ll automatically be sent a link to download a training template for an off-season hybrid triathlete. Which, conveniently, takes into account everything we’ve discussed here today.
That said, let’s go over some sample weeks.
Assuming you are training 1x/day, have a high likelihood to complete your sessions, and have access to all (or most) of the aerobic training modalities as mentioned above, the following is my preferred week’s structure.
Monday: full body strength
Tuesday: easy run or cycle (stationary or road)
Wednesday: SkiErg or swim
Thursday: lower body strength
Friday: upper body strength
Saturday: VO2max intervals (run)
Sunday: rower, AirDyne, or cycle (stationary or road)
Assuming you have access to less equipment and/or need more flexibility in your schedule (ie it is likely you miss a sessions), the following may be more appropriate:
Monday: full body strength
Tuesday: stationary bike ride followed by incline treadmill walk
Wednesday: full body strength
Thursday: ruck
Friday: full body strength
Saturday: easy run
Sunday: rest
If you have limited time in the week to train and can’t commit to 6 days per week, here is an option that might suit you better:
Monday: full body strength
Tuesday: cycle
Wednesday: rest
Thursday: full body strength
Friday: rest
Saturday: run
Sunday: rest
If you are looking to make as much progress as possible & are willing to have some double training days, here is a final sample:
Monday:
AM: SkiErg or swim
PM: Lower body strength
Tuesday:
AM: cycle (outdoor or stationary)
PM: Upper body strength
Wednesday: rest
Thursday:
AM: SkiErg or swim
PM: Lower body strength
Friday: Upper body strength
Saturday: long run
Sunday: rest
I hope it’s clear that there are many ways to skin this cat and there is no one right answer.
At the same time, I understand how overwhelming this can all be. If you want this all do for you or want an easier path to making progress, then consider applying for 1:1 coaching.
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