Concurrent Training: Using Cardio to Optimize Muscle Growth

For years bodybuilders have avoided cardio like the plague, fearing it will cause muscle loss and a reduction in strength.

However, like many of the old school principals in bodybuilding, recent research has established that this is a myth and in fact, new research has shown that cardio combined with weight training can even enhance muscle growth, anabolic hormones, fitness, and your physique.

Here’s how to use cardio effectively, minimizing the negatives and taking your physique to the next level.

A Brief History of Concurrent Training

Concurrent training describes the combination of cardio and weight/strength training.

It’s been tested for several decades in research and while initial research did show negative effects, the latest research in more advanced athletes, or, using different types of cardio training, have shown some impressive benefits^1,2.

This started with research from Dr. Hickson; he found that high frequency, high volume (i.e. lots of it, on a regular basis) did not provide the same positive adaptations when compared to strength training or endurance training alone.

Specifically, they found the first few weeks were the same between groups, however the last 3 weeks saw a sharp decrease in performance for the concurrent group, which may suggest the double sessions led to poor recovery and over-training^3,4.

Related: Coconut Cardio - An Early Morning Strategy to Get Super Shredded

In addition to this, a follow-up study further spooked bodybuilders away from cardio when it found that additional cardio or concurrent training decreased the anabolic response from resistance training⁴.

Based on this, it comes as no surprise that people started to fear cardio. However, this was several decades ago and also had several limitations, meaning these findings may be less relevant to the Muscle and Strength fans reading this.

Concurrent Training Benefits for Your Health

Fast forward several decades, we now have multiple studies showing that there were no negative issues when adding in cardio to your regime.

In fact, several studies have now shown a benefit, including increased muscle size and increases in anabolic hormones and of course, improved cardiovascular fitness^{9, 10}.

For general health and cardiovascular fitness, the added benefits of cardio are extremely impressive. As we know, cardio training can reduce the risk of heart disease, metabolic diseases such as diabetes, high blood pressure, certain cancers and many other diseases^{5, 6, 7}.

For any bodybuilder, these health benefits should not be overlooked, especially as resistance training may not elicit the same benefits on your cardiovascular health or long-term disease risk.

Additionally, another limiting factor for most bodybuilders is their cardiovascular fitness, especially when trying to perform metabolic resistance training, circuit training, or more advanced techniques such as supersets or dropsets.

However, this is just the tip of the iceberg, with other research showing it can enhance your muscle building and fat loss efforts. Let’s continue…

Concurrent Training Boosts Muscle Growth & Strength

You read the heading correct, recent research has started to show that when programmed sensibly and correctly, cardio + weight training can boost strength and even support muscle growth!!

After all, if you look at many mixed sports, you can see that cardio and strength training can blend quite well. For example, football (American), rugby, basketball, and most combat sports combine weight training and cardio on a regular basis. Most of these have both impressive cardio fitness and muscle mass or physique results.

In a recent study they put this to the test, utilizing a 21 week concurrent program on beginners. Participants were split into 3 groups, performing either:

1. Cardio training only,
2. Strength training only,
3. Cardio + Strength training.

After the 21 weeks, they found that no difference in power between the strength training only group and the concurrent group. Interestingly, the concurrent group improved muscle mass by the greatest amount compared to strength or cardio only (11% vs 6% vs 2%).

Lastly, the concurrent group also had the biggest improvements in VO2 max, the main marker of aerobic fitness. As you can see, it was a win-win for the concurrent training⁸.

While you may think this was an anomaly, another research trial tested the effects of biking followed by strength-based leg training. In this study, they also found that the concurrent training group improved peak power and strength by a similar amount to the strength training only group.

For muscle growth, like above, they saw the greatest improvement in the concurrent group, finding a 14% improvement vs only 9% in the normal strength group⁹.

Related: Fast Mass Program - The 4 Day Superset Split Workout

The final study which lays this myth to rest tested the biological responses within the cell, trying to highlight if there are any limitations from concurrent training from a physiological or cellular perspective. In this study, they found that concurrent training did not impact the main biological pathway behind muscle growth, known as muscle protein synthesis.

Additionally, they looked at specific muscle fiber changes, which is the most accurate way to track muscle growth, finding a whopping 300% greater improvement for the concurrent group⁵.

How to Maximize Cardio & Weight Training

Now you’ve seen both sides of the argument, the way you program will ultimately dictate your success when combining cardio and weight training.

Based on the current research, any potential negatives tend to occur from overtraining. For example, some of the initial trials were having participants performing several sessions of cardio and weight training, which could amount to 7 – 10 workouts per week.

Considering these subjects were likely young college students, with a poor diet, lifestyle and sleep pattern, it’s not surprising that the concurrent group became overtrained and had drops in performance.

Since then, many of the studies have taken a more sensible approach, using 4-5 workouts total per week. For a more experienced bodybuilder, who is optimizing other aspects such as diet and sleep, they could likely handle several sessions per week, without risking overtraining.

Ultimately, you can fit cardio and weight training into your regime, just pay attention to your recovery, levels of fatigue, and strength in the gym. If you notice a decline or plateau, it may be worth taking a few more rest days or dropping the cardio down by a session or two.

In addition to this, the specific muscle groups you train will have a large impact on the outcome. For example, cardio training signals the working muscles in a different manner to strength training.

Therefore, if your main goal was to build leg mass and strength, but you also performed lots of running, you may have a harder time trying to add mass than if you performed weight training for the upper body and combined it with running.

Related: The Ultimate 20 Minute Treadmill Workout to Get Shredded

Just like you wouldn’t train your legs 3 times in a 24 hour window, it would also not be wise to hit squats, run, and then also bike within a 24 hour period. Therefore, specific programming considerations must be made, trying to provide adequate rest days in between working the lower and upper body, just like you would with weight training.

Finally, a meta-analysis (large review of research) highlighted that non-impact forms of cardio may be a superior choice, because they require less recovery when compared to impact-based cardio exercises such as running¹⁰.

Example Concurrent Training Plan

Monday: Lower-body Weight Training
Tuesday: Upper-body Weight Training
Wednesday: Cardio Training
Thursday: Upper-body Weight Training
Friday: Lower-body Weight Training
Saturday: Cardio Training
Sunday: Rest

This is just one example split I love, which provides you with a perfect blend of weight training and cardio. Each muscle group is worked twice per week (upper/lower), which has been proven to be the most efficient training frequency for each muscle group.

It also allows for 2 cardio sessions per week, which can still elicit considerable adaptations without risking an impact on your weight training performance. Finally, this set up also allows a total rest day for each muscle group, meaning that every muscle group will get at least 48 hours rest.

Summary

When designed correctly, concurrent training can provide the best of both worlds, allowing for you to improve your fitness, health and even help keep you lean and insulin sensitive during a bulk.

As you can see in this article, the negatives only occur when taken out of context or when an individual does now allow for adequate recovery.

As long as you are being sensible and optimize your recovery, the addition of cardio may even help you add more muscle than strength training alone!