The Science of Building Muscle
I remember it like it was yesterday.
For 13 years I’d been inundated by images of big, strong, athletic-looking people bulging with muscles. No matter where I looked, I saw them. As a typical teenage male on the verge of puberty, I wanted to look just like them.
My first time in the high school weight room, I headed straight for the dumbbell rack -- who needs warm-ups? -- grabbed some 25-pound dumbbells and started busting out curls. Needless to say, this approach didn’t get me far. I burned out in about five minutes and just stood there, awkwardly, without any idea what to do next.
I know I’m not the only person who’s had this experience. In fact, I’m willing to bet that many of you could share a similar story.
Athletes want muscle. Bodybuilders want muscle. Powerlifters want muscle. Recreational lifters want muscle.
Muscle is in high demand, and I’m here to help you get it -- the right way.
The Good Stuff
Rather than go into satellite cells and myogenic pathways, let’s focus on information that applies directly to your training. In particular, let’s look at the three primary factors responsible for initiating muscular growth, also known as hypertrophy, in response to exercise:
- Muscular Tension
- Muscular Damage
- Metabolic Stress
Whether you’re trying to get superhero arms or bigger glutes, your success will depend on how well you manage these three variables.
Muscular tension, also known as mechanical tension, has a profound effect on muscle gain. It can be broken down into two types: passive and active.
A good example of passive tension is when you lie on your back and let someone stretch your hamstring. As the person lifts your leg, you feel tension when the muscle lengthens and reaches its end range. This is passive tension because you are not actively creating it. The tension is being created by the lengthening of your muscle.
Active tension, on the other hand, is when you physically contract a muscle. For example, flex your bicep as hard as you can. What you feel is active tension. It is isometric because the muscle is not changing length.
To induce muscle gain, you should expose your muscles to both types simultaneously, a concept known as dynamic tension. Dynamic tension occurs when you create active tension while moving. For example, flex your bicep as hard as you can again. Now extend and flex your elbow as if you’re doing a bicep curl.
That’s dynamic tension because you actively created the tension and took the muscle throughout a range of motion. Contracting your muscles through a large range of motion, however, is not enough, because tension is dependent upon load. Think of it this way: You can only generate so much tension against a lighter load, so more weight allows for greater tension.
Isometric contractions can be used to build muscle, but dynamic tension is superior for hypertrophic gains.
For a muscle to undergo hypertrophy, some degree of damage must take place. You have to break it down so your body can build it back up.
There are two ways to accomplish this:
- Do something new or unfamiliar.
- Hammer the eccentric portion of a lift. For example: while lowering the bar in the bench press or squat; it’s stretching a muscle while it’s activated.
Ultimately, both of these will cause muscular damage and ignite the remodeling process. Don’t go too far though, because too much damage is bad. For example, if you can’t walk down the stairs for a week because you crushed your legs on Monday you probably did too much. Generally speaking, soreness for 48 to 72 hours is acceptable.
Hang with me for a sec because this is going to get a little science-y.
You know that pump or burning sensation you get when working a particular muscle really hard? That’s metabolic stress, and it’s brought about primarily through anaerobic glycolysis, which is how the body turns glucose into metabolites such as lactate. Four factors really contribute to the onset of metabolic stress:
- If you contract a muscle hard enough you “pinch” the veins and prohibit blood flow in or out. Think of it like clamping a hose shut on two ends. This is known as occlusion of veins, which pools blood and does not allow it to escape.
- A lack of oxygen supply to the working muscles, known as hypoxia, occurs because of the lack of blood flow to the working muscle.
- A buildup of metabolites from the anaerobic glycolytic energy system and the hormonal response follows.
- Cells swell -- this is the pump feeling -- from the pooling blood.
Maximizing the Three Factors
How to optimize for tension, damage and metabolic stress:
Stick to the six to 12 rep range. This ensures you’re lifting something heavy enough to generate adequate amounts of tension and long enough to generate some metabolic stress.
Do multiple sets to keep volume high. Consider your body’s time under tension. Doing one set will not serve as an adequate stimulus because the time under tension is not long enough. Multiple sets maximize tension, damage and metabolic stress.
Keep rest time in the 60- to 90-second range. This allows muscles enough time to generate tension in the subsequent set but doesn’t provide too much recovery, so metabolic stress is still developed.
Vary movements. Change the angles and planes of movements to hit different aspects of each muscle. For example, alternate between decline bench, flat bench and incline bench to target different areas of your pectorals.
Perform exercises with a full range of motion. This lets you activate more muscles and create more tension, metabolic stress and muscular damage.
Work close to failure. Pick a weight that leaves two reps in the tank when you’re done. You can occasionally work to failure, but most of the time you’ll want to leave a few in the tank. For example, on a set of 10 you’ll want to pick a weight you could only do 12 times. This ensures you’re using a large enough load.
For tempo, the concentric portion of the lift muscle shortening -- also known as pressing in the bench press and standing up in the squat -- should be performed with fast to moderate speeds -- about 1 to 3 seconds -- while the eccentric portion of the lift should be performed with moderate to slow tempo -- about 2 to 4 seconds.
Lift something heavy, performing 1 to 5 reps, at least once a week. It maximizes the release of hormones such as testosterone, human growth hormone and insulin-like growth factor.
You can do everything right in the gym, but if you don’t handle your business in the kitchen, it won’t matter. Synchronize your diet with your program and your goals. This isn’t a scenario where you can have one without the other.
Readeres – Are you working on building muscle? Do you incorporate any of the techniques mentioned in the article? What has worked best for you? Leave a comment below and let us know!
- Journal of Strenth and Conditioning Research: The mechanisms of muscle hypertrophy and their application to resistance training
- Essentials of Strength Training and Conditioning, Thomas A. Baechle and Roger W. Earle, editors
- University of California San Diego, Muscle Physiology
- Medicine and Science in Sports and Medicine: Motion into mass: how does tension stimulate muscle growth?
- Clinical Orthopaedics and Related Research: Effects of exercise on senescent muscle.
- Univeristy of New Mexico: Hormonal Responses to Resistance Exercise Variables
- Medical Hypotheses: The anabolic benefits of venous blood flow restriction training may be induced by muscle cell swelling.
James Cerbie is certified by the National Strength and Conditioning Association, Precision Nutrition, USA Weightlifting and CrossFit. He's worked with athletes from middle school to professional level, is the owner of Rebel Performance and specializes in helping people be more than fit.