Can cardio increase muscle growth?

By Coach Hunter Bennett

While some people suggest that combining cardio with weight training can hurt muscle growth, recent research indicates that aerobic exercise might increase it.

This article explores why integrating cardio into your routine can boost muscle growth, and explains how you can build cardio into your training.

Can cardio increase muscle growth?

A recent study investigated the effects of performing a block of aerobic training prior to resistance training on muscle growth.

The study involved 14 trained adults, and used a within-subject design where each participant’s leg underwent a different 16-week training intervention.

One of the legs underwent six weeks of cycling made up of three 45 minutes sessions per week at a moderate intensity.

During this time the other leg did nothing.

Both legs then underwent 10 weeks of intense lower body strength training, comprised of leg press, leg extension, leg curls, and calf raises, all performed for 3 sets of 10 to 12 reps, with the last set pushed to failure.

What did they find?

There were a few key findings that came out of this study.

1. Increased Capillary Density: Firstly, legs that underwent aerobic training prior to resistance training showed a significant increase in capillary density compared to the other leg. This is important, because capillaries deliver oxygen and nutrients to your muscles, allowing better performance and recovery.

1. Higher Satellite Cell Content: Secondly, the aerobically trained legs also had higher satellite cell and myonuclear content than the other leg at the end of the study. These two factors are crucial for muscle repair and growth.
2. Enhanced Muscle Fiber Growth: Finally, the legs that did the cardio also saw substantially greater muscle growth than the legs that did nothing for the first six weeks. This was likely due to the two factors mentioned above.

In short, the findings suggested that cardio can increase muscle growth by enhancing your ability to recover and repair muscle tissue.

How can you use cardio to increase muscle growth?

To leverage the muscle growth benefits of aerobic training, there are a few things you could do.

1. Do some cardio: We have written about this extensively before (check out other articles HERE and HERE), but we’ll touch on it again briefly. Something as simple as 1-2 light jogs, rides, or rows (or any other form of cardio) is enough to increase fitness. If you need to do both on the same day, try and do your weight training first.

1. Try Different Training Phases: If you really want to push this aerobic training thing, then why not spend 6-8 weeks making it a priority. For a specific period, you could reduce your weight training down to 2-3 quick sessions per week and bump up the cardio.
2. Incorporate High-Rep Accessory Work: Lastly, if you are going to find it hard squeezing more training sessions into your routine, you could bump up the reps on your accessory exercises. While the evidence is not clear here, perform sets of 20-30 reps should stimulate similar adaptations as aerobic training, which could yield the same effect.

Can cardio increase muscle growth: Take home message.

New research suggests that aerobic training can increase muscle growth by improving your ability to recover and repair muscle tissue.

By adding in cardio into your routine, or simply incorporating high-rep accessory work, you can optimize your hypertrophy outcomes.

Want to read more? Check out our article on minimalist strength training