Your Evidence Based Guide to Building Muscle (Part 2)

This is part 2 of your ultimate guide to building muscle: What Exercises should we pick?

With a scientific understanding of what stimulus we need to target to trigger muscle growth, let’s talk now about how we practically achieve that.

What exercises should we choose?

First off, we have to choose the right exercises, namely exercises that allow us to take the muscle group we are trying to grow to muscular failure. An exercise can be deemed effective for muscle growth if we can do this, and less effective if something else, i.e. balance, coordination, or our aerobic system, fails first. More broadly speaking, that leaves us with exercises that would fall in the category of resistance training or weight lifting. For example, the stair master, or any type of cardiovascular exercise, is not going to be effective for building muscle because your cardiovascular system will fail before you could push the muscles of your legs or glutes to failure. You might get an intense accumulation of metabolites, depending on the strength of your cardiovascular system relative to your legs, but metabolite accumulation alone is not sufficient to grow muscle, outside of beginners.  

Stability

Now we understand we are in the realm of resistance training, let’s be more specific about what types of exercises are better or worse for building muscle. One primary variable we should look at is stability. Exercises that have the most external stability, i.e. those in which our body does not have to work as hard to stabilize itself or balance, are going to be the most effective for building muscle. This is true for a couple reasons. For one, our body’s ability to balance itself is a major restriction on how much weight we can lift. Bosu ball single leg squats are never going to be an effective exercise for building muscle because our vestibular system, responsible for balance, will fail far before our quads or glutes. The less hard our vestibular system has to work the more we can bias the specific muscles we want to grow. 

Secondly, not all muscle fibers in a single muscle activate when we do an exercise. Every muscle is made up of thousands of individual muscle fibers, and only those smaller, type 2 muscle fibers activate when we lift weights that are light. These fibers also happen to not grow very effectively. For example, picking up a 200 pound weight is going to recruit more total muscle fibers, and more of the ones we want to recruit, than a 100 pound weight, especially if 200 pounds is close to the most you can do on that exercise. When we choose exercises that are highly stable, that don’t tax our balance, we can lift the heaviest weights possible, activating the most total muscle fibers through the exercise and the ones we want to activate to grow. 

What does this mean practically? Machines are going to be some of the best choices for building muscle, because they provide a ton of external stability. A machine chest press is probably a more effective exercise than a dumbbell chest press if your only goal was growing your chest as much as possible because the muscles of your rotator cuff have to work much harder to keep the dumbbells from falling on your face as you fatigue your chest. But, practically speaking, both are going to be great choices. Not every exercise you do should be on a machine necessarily, as you get more proficient in a relatively unstable exercise, you will get better and better at taking the targeted muscle to failure.

While there are a lot of good choices, where you can go wrong is choosing exercises that are impossible to stabilize effectively. Anything bosu ball is out. Anything single leg, where your opposite leg is not rooted on the ground or you are holding onto something for support, is out. A great example is the single leg rdl. Just bring a bench close to you to hold on to for support and you will instantly be able to do 20-30 pounds more. Take the example of a bent over barbell row versus a chest supported dumbbell row. All else being equal, the chest supported dumbbell row is going to be more effective for specifically the muscles in your upper back and lats compared to the bent over barbell row because in the latter exercise your lower back will fatigue before your upper back. This does not make the bent over row a bad exercise at all, if your only goal was to train the muscles of your upper back as effectively as possible the chest supported row is a better exercise for that goal. 

Resistance Curves

Another important factor in exercise selection is the question of where in the rep is the exercise the hardest. Every exercise has something called a resistance curve, which shows where an exercise is the hardest due to changes in leverage, and will depend on whether you are using free weights, cables, or machines. For the majority of your hypertrophy training, you want to choose exercises that are biased towards being hardest in the part of the exercise where the muscle is in its most stretched position. The nice thing is that the majority of the most common resistance training exercises done with free weights fit this criteria. Squats, lunges, deadlifts, rdls, bench presses, and overhead presses are all exercises in which the hardest part of the rep is at the bottom. 

Should you do compound exercises or isolation exercises?

It’s common for people trying to grow muscle to do a lot of isolation exercises, i.e. those that only involve one joint moving at a time. Think leg extension, hamstring curl, bicep curl, lateral raise etc. While these exercises are good to have in a program, the basis of your program should be compound exercises, or exercises that involve multiple muscle groups, simply on the basis that they train more muscle tissue in the same amount of time. Unless you have 2 hours a day 6 days a week to train, your main goal with your training should be to impart as much of that muscle building stimulus as possible in the least amount of time. Compound exercises like squats, lunges, presses, and rowing always have been and always will be the most important in your program. 

Ancillary factors

There are a few other important factors to take into account, most of which are highly individual. What do you feel when you do an exercise? Do you feel the target muscle stretch and contract hard, or do you feel something other than what you are ostensibly trying to train? Do you get sore the next day? Do you enjoy the movement? Are you experiencing joint pain? These are questions that only you can answer on a day to day or week to week basis. In general, if you feel the muscle really well in the exercise, it’s slightly sore the next day, you enjoy doing it, and aren’t experiencing any pain as a result of the movement, it’s probably a great exercise for you. If the answer to one of those questions is no, then it may be worth looking at your technique, or swapping it out for something similar. 

How Often Should I Change Exercises? 

If you follow the guidelines in the paragraph above, and the answer to all those questions is yes, you probably don’t need to change exercises very often. Most fitness professionals will tell you to change exercises and programs every 6-8 weeks, but this has not been shown to make an impact on muscle building, specifically. I would much rather someone keep an exercise in their program for too long rather than too little. Don’t fix what is not broken.