Strong Heart for Strong Arms

Muscle growth is a lot like a group of cells trying to expand and also like a plant trying to reach its fullest potential. Let’s go with the plant as cancer is typically a rough analogy. So when a plant is growing it can be limited by a variety of factors such as genetic potential, location, climate, nutrient resources, etc. For the purpose of this thought we are going to focus on nutrient resources.

The efficiency of a plant to obtain resources is incredible. Whether it is leaf placement to maximize sunlight or toxic pheromones released into the soil that it can out compete a neighboring plant for resources. House plants on the other hand are typically limited by the size of their pot for example (given that all else is taken care of and optimized). In a certain size flower pot the plant roots can only expand so far, and there is only so much soil to provide various nutrients. But when that same plant is transplanted into a larger pot with more soil the plant will have the opportunity to grow. The root system can now bring in a greater quantity of nutrients so that it is no longer the limiting factor.

To bring this back into the gym let’s talk about muscle gains and cardio. Cardiac conditioning can be the limiting factor. As muscle grows it requires more. It requires more blood flow to bring in oxygenated blood and to carry away deoxygenated blood and metabolic byproducts. It requires more blood flow to bring in fresh ATP. It requires more vasculature to extend into the newly grown hypertrophic regions. It places a greater cardio vascular demand.

I have fallen into this pit too many times. It incredibly easy to neglect cardio. It’s not fun. It’s time consuming. And it doesn’t directly make you stronger. So I would do just that—I would neglect it. And I know I’m not alone in this one; almost every gym addict I pass on the staircase is out of breath—but that’s not the point.

Recently, I’ve changed up my resistance training routine to do a little bit more volume—GVT style of working out. But I hit a road block. In the beginning I was able to do 80lbs for 10 reps for the first 5 sets on dumbbell bench press. Then the following 5 sets tapered off with the final set getting only about 6 reps. I more or less maintained this for 4 weeks without being able to hit the target of 10 sets of 10 reps. And yes, I did try lighter weight but for the sake of time I decided to skip over the bulky details.

But this is when it hit me. I realized that my muscles were fatiguing because I haven’t been doing any cardio—like none. The only cardio included is my fast pace of working out. Nonetheless, I’ve been hurting all of my potential muscle gains by being lazy.

The current literature out there does suggest that when cardiac conditioning is added to a resistance training program muscle hypertrophic potential can be maximized. The caveat to this is that concurrent high volume endurance and resistance training (i.e. in the same workout) may be detrimental to maximal hypertrophic gains. It is suggested in a paper by Kevin Murach to separate exercise bouts by 6-24 hrs, and to also adapt ways to minimize volume by using HITT training.

Various other articles also suggest that endurance training alone can increase skeletal muscle size in older adults.

Long story short, the evidence is no solidified but is suggestive. Intermix some HIIT into your workout regimen to maximize your gains and to also not get out of breath when tying your shoes.

Konopka, A. R., & Harber, M. P. (2014). Skeletal Muscle Hypertrophy after Aerobic Exercise Training. Exercise and Sport Sciences Reviews, 42(2), 53–61. https://doi.org/10.1249/JES.0000000000000007

Murach, Kevin.Bagley, James R. Skeletal Muscle Hypertrophy with Concurrent Exercise Training: Contrary Evidence for an Interference Effect. Sports Med. DOI 10.1007/s40279-016-0496-y

Petré, H., Löfving, P., & Psilander, N. (2018). The Effect of Two Different Concurrent Training Programs on Strength and Power Gains in Highly-Trained Individuals. Journal of Sports Science & Medicine, 17(2), 167–173. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5950732/