The Danger of Muscle Imbalances and the Importance of Symmetry

Symmetry is a beautiful thing. It seems to be nature’s preferred state, at least in the structure of organisms: two eyes for stereoscopic vision (the better to hunt you with), two legs of equal length for injury-free traversal of the environment, two hands, two arms. For all intents and purposes, the two sides of the body are approximate mirror images of each other, with corresponding muscles and ligaments and tendons. Our anatomical symmetry is obviously a product of evolution, because a balanced body simply works better. Kids born with right legs an inch or two shorter than the left are more prone to injury, just as cars with bigger wheels on the left will be more prone to disrepair. Objective human beauty is determined by symmetry of the facial structure, as if we’re innately drawn to balance. A balanced body structure, too, is objectively attractive, because it connotes strength and competence in matters of survival (war, hunting, protection). It becomes clear that if symmetry weren’t important for survival in this environment, it wouldn’t have been selected for, we wouldn’t be drawn to it, and plants and animals would have assumed entirely different forms. Maybe we’d be amorphous blobs just kind of oozing around (as opposed to the amorphous blobs with legs and arms that presently populate our planet).

But we’re not all amorphous blobs (not yet at least – the American populace sure is doing its darndest). Our bodies want to be perfectly balanced. They function best when everything – muscles, tendons, bones – are equally healthy and strong. When we make a movement, every muscle has to pitch in and do what it can (to the best of its ability). If a single muscle falters, the others have to pick up the slack, and the entire production is compromised. Sounds a bit like Communism, eh? It may not work in government, but it’s definitely the best way to govern your body.

Art de Vany talks about the X-look: a “symmetrical balance of mass in the shoulder girdle, upper chest and back, the calves and lower quads.” The X-look indicates muscle balance – a very, very good thing. Balanced muscles allow our bodies to function the way they’re supposed to function. Injuries become rare, strength and performance optimize, and you start to give off the positive evolutionary cues that say, “Hey, strong, capable human here! I can hunt, slaughter, and haul a deer back to camp, then pass on my superior genetics to my kids!”

But despite the obvious importance of maintaining muscle balance, people seem to have missed the memo. Oh, sure, things are getting better, and “functional fitness” is growing by leaps and bounds (take Crossfit, for example, which only gets more popular), but the average gym goer is still woefully ignorant of muscle balance. And if he or she is familiar with the term, they’re probably just focused on keeping their biceps symmetrical with no consideration of overall function. Just how prevalent are imbalanced muscles, really? Well, take a quick look at your gym’s inhabitants. You’ve got the old guys pouring buckets of sweat everywhere despite languishing on the chest fly machine for hours at a time. Or how about the over-the-hill bodybuilder who has somehow managed to keep up with some semblance of a routine while failing to keep up with the regular waxing and deodorant applications (there’s nothing quite like discovering a cache of curly black hairs in your gym bag upon returning home). Then there are the frat boys twisting their bodies into unnatural contortions just to target their medial tricep and get that pump going.

But my absolute favorite has to be the top-heavy, dreidel-shaped buffoons sporting massive chests and bulging biceps along with bird shoulders, chicken legs, and the back development of young boys. These guys are the perfect pictures of muscle imbalance. Still, they thrust these chests proudly forward and strut around the gym, pausing only to scratch their arms in contrived positions that show off their biceps whenever there’s a nearby mirror. Oh, and they love doling out unsolicited advice. They now know better than to accost me (especially when I’m lifting) with that nonsense, but I see at least a few guys fall for their “charms” daily. It might actually be funny if it weren’t so damn dangerous. For every newbie they pressure into working out their way – isolation exercises, for the most part – that’s one more human who’ll be plagued with chronic muscle imbalances, possibly for life.

Muscle imbalances can manifest with devastating consequences. Take lordosis, an abnormal inward curve of the spine, which is sometimes caused by weak hamstrings. Heavy squatters who focus solely on the quads without engaging the posterior chain (glutes, hamstrings) often fall prey to lordosis of the spine. In fact, squats that ignore half of the lower body aren’t technically even squats; they are fundamentally flawed free-standing quad presses. Continue to overwork your quads without including your hamstrings, and you’ll probably end up with poor posture.

Muscle imbalance is also terrible to look at. The guy with huge arms and skinny legs might impress his buddies at the gym, but most casual onlookers will be horrified. The balanced, symmetrical X-look is far more aesthetically pleasing – even if we aren’t quite conscious of it, we are attracted to that body structure.

Muscle imbalances set you up for injuries. Like the boy with a shorter left leg, the guy with weak hamstrings is setting himself up for tattered cartilage and bad knees. The knee is designed to work with everything working in perfect harmony, but when your muscle balance is out of whack, undue stress is placed on the joint. Same goes for other areas of the body, too. In the real world, functional movements require the enlistment of multiple muscles. Carrying a buddy who sprained his ankle and is unable to walk requires leg, core, and shoulder strength. If you’re lacking in one area, the rest of your muscles will try to make up for it. That means muscles that are designed for one thing will have to do another (in addition to performing their original task) – and you know how opposing one’s natural inclinations usually goes.

What causes muscle imbalances? For one, poor form. Taking the squat example from above, it doesn’t mean much if you’re squatting (or deadlifting, or pressing, or doing any of the compound lifts) with poor form. At worst, you risk injury, and at best, you risk favoring one muscle group over another. A true squat is supposed to be a total body effort, with the quads pushing, the hamstrings pulling, and the glutes activating (not to mention the torso-lever supporting it all, which requires equally competent abs and lower back muscles).

Isolation exercises also contribute to muscular imbalance. As a rule, the leg extension machine doesn’t work anything but the quadriceps. Unless you’re a bodybuilder going for ridiculous quads, you should avoid this machine at all costs. Even if you supplement your “leg day” (arm, chest, back, and leg “days” are another pet peeve of mine, but more on that later) with some hamstring curls, calf raises, and glute pushes, you’re still contributing to muscle imbalance. Each individual muscle might be strong in its own way, but they don’t work together. Try to lift a heavy rock after a year of leg extensions, hamstring curls, and calf raises, and you won’t know how to coordinate each muscle to complete the movement. Isolation exercises don’t improve your performance in functional activities (sports, hunting, lifting heavy things in real world terms); they increase your ability to only perform that specific isolation exercise. A machine lover who can leg press a thousand pounds can’t squat the same amount, but a guy who squats a thousand pounds can probably double that amount on the leg press. The woman who curls a ton and loves the reverse back fly may have big biceps and a defined back, but I bet she can’t do fifteen pull-ups like the devoted Primal fitness buff might.

The very idea of “leg days” or “arm days” is counterproductive to real fitness and contributes to muscle imbalances. Did Grok have “leg days”? Did he ever spend a few hours just curling a heavy rock so his biceps would grow? No! The body is meant to function as a machine of interlocking parts, every single one of which is integral to overall performance. When we mentally separate our lifting days and focus on specific body parts, we start to think of our muscles as islands unto themselves, and eventually they’ll start to function like that – imbalanced and totally cut off from the rest of the muscles. What’s ironic is that the people who do this really think they’re balancing things out. If they only knew…

How do we promote muscle balance and fight muscle imbalance? Pretty simply, by exercising the right way. Luckily, Primal exercises are all about promoting proper muscle balance. Big, compound movements force us to use every muscle in our bodies correctly, and the best way to train for these big, compound movements is to just do them. Even if you’re worried about the size of your biceps, resist the urge to curl. Instead, just do a few more pull-ups and know it’ll all work out in the end. Also, be aware of your form, and get coaching (either in person or via videos/info on the web) on the more complex lifts to ensure you’re actively engaging all the requisite muscles.

And so, perfect Primal muscle balance is about symmetry on the micro level, between opposing muscles – the hamstring/quad, the bicep/tricep, the abs/back – and on the macro level – the entire body working in concert to perform a task. Total body muscle balance, then, requires individually balanced muscles. To isolate our muscles and go for an imbalanced look is to reject our essential natures – that of symmetrical beings constantly searching for balance in all areas of life – and invite ruin and chronic injury. To use our muscles as a cohesive, united force is to promote optimum health, freedom from injury, and better results.

On a final note, thanks to reader Sterling for a good laugh:

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending more than three decades educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates flavorful and delicious kitchen staples crafted with premium ingredients like avocado oil. With over 70 condiments, sauces, oils, and dressings in their lineup, Primal Kitchen makes it easy to prep mouthwatering meals that fit into your lifestyle.

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