In order to feel, look, and perform at your best, you need to build a number of different aspects of your fitness.

Some of these include: power, strength, high intensity endurance, and low intensity endurance. I argue this because each one has unique components that contribute to your well-being.

Building strength and power is the best ways to ensure a health musculoskeletal system as you age [1]. In addition, having a high VO2max (a measure of endurance) is one of the best predictors of longevity [2].

Not to mention, having multiple styles of training in your program can keep it exciting, which can promote greater adherence.

 

The problem is that building all of these effectively is a difficult task. Hell, building one of these at a time can be hard.

However, with a well-designed program, it’s doable. I’d even argue results can be maximized this way.

So, the aim of this article is to provide you with the best practices for constructing hybrid or concurrent programs.

 

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 in much more detail here.

 

Resistance Training Volume & Intensity

The resistance training portion of the program pertains to modalities including strength training and power training.

These can be further broken down into weight training, calisthenics, plyometrics, olympic lifting, ballistics, etc.

In essence, any movement in which the mechanical capability of the musculoskeletal system is the limiting factor.

 

For these modes of training, it’s generally best to keep intensity high and volume lower.

By “high intensity,” I am referring to loads equal to or greater than 80% of your 1 repetition maximum with sets being taken close to failure (1-2 reps in reserve at the end of each set).

 

There are a few reasons this is important.

To start, intensity and volume tend to have an inverse relationship.

The lower intensity you train, the higher volume you can handle. The lower volume in which you train, the higher you can push the intensity.

Given that we have other fitness variables to improve, we have no choice but to opt for lower volume. Thus, intensities of each set will be high. Recent research has also shown that strength & hypertrophy are maximized on lower volume programs when higher intensities are used [6].

 

Still though, we need to make sure there is enough resistance training volume overall to elicit adaptations.

In my experience and opinion, somewhere between 6-9 sets per muscle per week works best.

The research on the subject tends to suggest that 10-20 sets is best, [7] but such data is only shown when one muscle group is trained and one exercise is given for the muscle group. It’s still helpful information, but in the real world you have to take into account all the other muscle groups you are training as well as the endurance training.

Time-saving strategies for strength training

Whether you have limited time or want to get more work done in the same amount of time, there are two main strategies to keep in mind.

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.

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.

Conditioning/Endurance Volume & Intensity

When you’re programming endurance training, the two things you manipulate are 1) intensity and 2) duration.

The adaptations you get from long duration & low intensity work are different than those you get from short duration & high intensity work.

For best results, both should be done.

Intensity of endurance training or conditioning is typically measured in heart rate.

The 5 zone model is commonly used, which goes as follows:

• Zone 1: 50-60% MHR

• Zone 2: 60-70% MHR

• Zone 3: 70-80% MHR

• Zone 4: 80-90% MHR

• Zone 5: 90-100% MHR

  • MHR = maximum heart rate; which can be estimated using the formula 220 - your age = MHR

How you manipulate these two variables is highly dependent on what your overall goals within endurance training are and what your starting point is.

Assuming the goal is building endurance in general, such as being able to run longer distances, a commonly recommended framework that works well is the following:

• ~75% of your work should be done at zone 2 or 3 (easy to moderate)

• ~20% of your work should be done at zone 4 (moderate to hard)

• ~5% of your work should be done at zone 5 (hard to very hard)

Understand that the work percentages given specifically pertain to the cardiovascular exercise you do throughout a week.

 

Conditioning/Endurance Exercise Selection

To start, you can generally only say you have high or low endurance in a given endurance event.

Yes, there does tend to be considerable overlap between modalities, but the point is that being a good runner won’t translate perfectly to a strong swimming performance & vice versa.

In many ways, the primary influence to your exercise selection should be whatever endurance event you want to improve; whether it’s running, swimming, rowing, or anything else.

That being said, some endurance modalities cause less fatigue than others.

When half of your training goals pertain to building strength as well, spending time on these less fatiguing modalities is good practice.

In general, what makes an endurance exercise fatiguing is:

• Impact

• Eccentric loading (eccentric = the lengthening of a muscle; the lowering of a weight; the ‘negative’ portion of a bicep curl)

An exercise that does not have these will be less fatiguing.

The main reason why running is more tiring than riding a bike is because of the presence of these two variables.

So, exercises lacking these that are worth your consideration include:

• Cycling

• Incline treadmill walking

• Rowing

• SkiErg

• AirDyne

• etc.

Technically swimming fits this bill also.

The only reason I didn’t include it is that swimming tends to sufficiently wipe you out when you’re new.

The other listed exercises will not fatigue you even on your first time doing them (generally speaking).

Even if your ultimate endurance ambition involves running specifically, incorporating these into your week is a good idea.

The mix could look something like 50-75% of your endurance training being running, and 25-50% of it being one of the listed exercises.

 

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 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 a long, easy run on Monday or Wednesday, but you probably shouldn’t do a threshold run on either of those days.

 

Weights & cardio on the same or separate days?

An investable question you run into when designing a concurrent program is whether you should separate the resistance training and conditioning to separate days or keep them on the same day.

 

In my opinion, the first factor to consider here is how many days you have available to train per week. I personally follow the template below in regard to this:

• 2-3 training days per week: same session

• 4 training days per week: can go either way

• 5-7 training days per week: separate sessions

 

It’s generally considered best practice to have the conditioning and resistance training on separate days.

However, what really matters most is making sure you have enough overall volume of each throughout the week (volume prescriptions discussed in previous sections).

That tends to be easier to do when they are done in separate sessions. However, doing your conditioning and resistance training in separate sessions might not be feasible for some busier folks.

References

1. Age-related muscle anabolic resistance: inevitable or preventable?

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2. Survival of the fittest: VO2max, a key predictor of longevity?

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3. Relationship between oxygen uptake kinetics and performance in repeated running sprints

   • PMID: 15976999

4. Short-term aerobic conditioning prior to resistance training augments muscle hypertrophy and satellite cell content in healthy young men and women

   • PMID: 35971745

5. Resistance Exercise for Improving Running Economy and Running Biomechanics and Decreasing Running-Related Injury Risk: A Narrative Review

   • PMID: 35878109

6. Influence of Resistance Training Proximity-to-Failure on Skeletal Muscle Hypertrophy: A Systematic Review with Meta-analysis

   • PMID: 36334240

7. Dose-Response Relationship of Weekly Resistance-Training Volume and Frequency on Muscular Adaptations in Trained Men

   • PMID: 30160627

8. Haff, Gregory G., Triplett, Travis N., 2016, Essentials of Strength Training & Conditioning, 4th edition.

9. Physiological responses during intermittent running exercise differ between outdoor and treadmill running

   • PMID: 28549220

10. Sand training: a review of current research and practical applications

    • PMID: 23968257

11. Sousa, António C. PhD1,2; Neiva, Henrique P. PhD1,2; Izquierdo, Mikel PhD3; Alves, Ana R. PhD1,2; Duarte-Mendes, Pedro PhD4,5; Ramalho, André G. MSc4,5; Marques, Mário C. PhD1,2; Marinho, Daniel A. PhD1,2. Concurrent Training Intensities: A Practical Approach for Program Design. Strength and Conditioning Journal 42(2):p 38-44, April 2020. | DOI: 10.1519/SSC.0000000000000520

12. García-Orea GP, Rodríguez-Rosell D, Ballester-Sánchez Á, Da Silva-Grigoletto ME, Belando-Pedreño N. Upper-lower body super-sets vs. traditional sets for inducing chronic athletic performance improvements. PeerJ. 2023;11:e14636. Published 2023 Feb 21. doi:10.7717/peerj.14636

13. Sødal LK, Kristiansen E, Larsen S, van den Tillaar R. Effects of Drop Sets on Skeletal Muscle Hypertrophy: A Systematic Review and Meta-analysis. Sports Med Open. 2023;9(1):66. Published 2023 Jul 31. doi:10.1186/s40798-023-00620-5