The study, “Prevalence of Optimal Metabolic Health in American Adults: National Health and Nutrition Examination Survey 2009-2016,” was published online Nov. 28, 2018 in the journal Metabolic Syndrome and Disroders. ​I propose that similarly few Americans are musculoskeletally healthy.

While there may be some debate over the absolute best criteria to use to determine metabolic health, the five used in this study are clearly important. For instance, some clinicians argue that insulin level is a more significant barometer of health than glucose level.

For musculoskeletal health, as I have written before, I propose that the criteria are: full joint mobility; full strength; full nerve extensibility; and full, pain-free function. Function means being able to do what you want to do with your body and not being limited by musculoskeletal problems. (Be aware: not being able to do something can be limited by fitness, not problems.) Yes, full, pain-free function is less objective and more individual than the other three metrics, but it is still relevant and critical.

Could you make the argument that being able to walk 1 mile in under 15 minutes should also be a criterion? Or that normal musculoskeletal health means you should be able to get up from a chair without needing your hands? Sure. Those demands, though, usually require that you meet the basic criteria. There’s certainly room for debate, and we do have valid tests that measure people’s ability to do things like this.

However, whichever metrics we use - the simple ones I propose or more involved ones - it’s clear from my experience (ten years working in orthopedics) that not many Americans would fit the criteria for being musculoskeletally healthy. -- Laura

Joint mobility is an extremely important piece of data when diagnosing and treating orthopedic disorders. Even though testing a joint’s mobility is easy, it is rarely done well. While the length of a muscle may matter, the strength very rarely does. A tight muscle (which is rare) may reduce a joint’s range of motion in a specific direction (the direction in which the tight muscle is put on stretch), but weakness is rarely a factor.

A muscle would have to be significantly inhibited and/or significantly weak for the patient not to be able to achieve full active range of motion, especially with gravity eliminated or gravity assisted procedures. (Remember: muscle inhibition usually comes from a nearby joint or spinal joints.) Muscle weakness does not impact passive range of motion, which is when the joint is moved by something external (not internal muscle strength). If a joint doesn’t move well - passively and/or actively - my investigation starts with joints themselves (local and spinal). If that proves fruitless, only then will I consider that muscles are causing reduced joint range of motion. -- Laura

People end up replacing and fusing their joints, not their muscles. We must focus on keeping joints healthy, not just muscles. Yes, having muscle strength helps support joints, and training muscles for endurance and strength inevitably moves joints. But focusing on joints is different than simply getting the byproducts of working out muscles. The best way to monitor joint health is monitoring range of motion. The great news is that maintaining range of motion only takes minutes a day. It’s easy to preserve full motion with self-mobilizations once you have it and once you understand the factors that decrease it. For example, you can check your shoulder mobility in one minute. Want to strip it down to the bare minimum? I’d say make sure you can reach all the way up your back and that you can elevate your arm all the way up, out to the side.

Please keep working out those muscles - they're important for musculoskeletal as well as overall health. It’s easy to see, though, that joints more often fail, not muscles. In addition to controlling lifestyle factors, we can also very easily “exercise” our joints. The most important thing is to get joints all the way to end range (especially your spine!) and make sure you can continue to do so. This is what I teach my patients how to do.  --Laura

The glutues maximus, gluteus medius, and gluteus minimus are innervated (powered) by the nerve roots L4, L5, S1, and S2, which exit the spinal cord in the low back. A muscle can only achieve optimal strength and efficiency if it’s getting an undisturbed supply of electricity. I hear loads and loads of people talk and talk about problematic weak glute muscles. I usually don’t find weakness. Instead, I find that it’s almost always inhibition - a fuse box (spine) problem. Most low back problems are at the levels L4, L5, S1. Is it any surprise then that the nerves to the glutes may be compromised? There does not have to be back pain for a nerve irritation to be present.
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If we prove that your nerves are indeed working well (which we do by clinically moving your low back, and sometimes hip, repeatedly - not by looking at an image), and your glutes are still problematically weak, then we can begin all those glute exercises such as squats, lunges, donkey kicks, clamshells, crab walks, sidelying leg lifts, lateral step downs, bridges, and so on. If a professional wants to diagnose “weakness,” then he/she better have first at least ruled out inhibition. Not only does that save months of work, but it gets at the real diagnosis. When a muscle doesn't demonstrate the strength it should, I check the fuse box. -- Laura

In orthopedics, the core comprises a specific group of muscles in the trunk/pelvis. (Others use core generally to mean trunk.) Core muscle strength is beneficial. Just as arm, chest, and foot strength are beneficial! Core muscles are not exemplary. They’re no more our “foundation” than our foot muscles or those running the length of our spine.

Many erroneously treat orthopedic low back pathology by strengthening the core. Assuming core muscle strength can be accurately assessed, if one or more of them is weak, the question is why. Muscles become weak (and painful) from pulls/tears. However, these are very rare when it comes to the large muscles of the core. (Tears follow a consistent, predictable pattern, too, which should make them obvious to an attentive clinician.) Pain can create weakness, but absent a clear tear, the pain usually originates from something other than the muscle.
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The number one reason any muscle is weak (the large majority of cases) is because its electricity from nerves has been inhibited – either at the spine or extremity joints. It’s a joint problem. Therefore, in most cases strengthening a weak muscle (or entire group!) is simply attacking a symptom, which won’t fully resolve the problem. -- Laura

I remember learning about dead butt syndrome (DBS) during a presentation at the clinic where I worked several years ago, two years into my career. I believe the sales rep was there to push taping products, but this topic somehow came up. (Please note: while some refer to all the gluteal muscles becoming weak, others specify the gluteus medius muscle in particular.) This gentleman explained that since people sit all day without using their gluteus muscles, they become weak. Made sense to me! And it had a fun name.

However, when I began using the term with patients whose gluteus medius muscles were in fact weak, and fielding patients' questions regarding the topic, I became skeptical. For one, if sitting dormant all day was the root cause, why wouldn't mostmuscles weaken? And, secondly, if it was sitting combined with lack of daily use of the gluteus medius muscles - lack of moving the hips laterally - that was the trigger, wouldn't the lateral movers of other joints suffer then too?
So I did a bit of "research:" I read a few articles intended for the public. The consensus is that DBS not only affects expert sitters, but also people who exercise, but who don't target the glute muscles enough. That sounds strange. Those could be very different cohorts. Or, the exercisers could also be expert sitters when they're not moving. Here are my two chief complaints with what I found to be the commonly proposed etiology of DBS:

1. Asserting that the glutes are weak because of reciprocal inhibition does not resonate with me. This argument states that, with prolonged sitting, hip flexors get tight and contracted and therefore inhibit the muscles opposite them - the glutes. For starters, tight and contracted are not necessarily the same thing. I'll allow that hip flexors may get tight the more we sit with them maintained in a shortened state, but given they get some stretch with each step we take, pathological hip flexor tightness is a hard sell for me. Very often what is diagnosed as hip flexor tightness is actually femoral nerve tightness. (There are clinical tests to distinguish between the two.) Additionally, hip flexors don't contract, that is, actively work, while you're seated. They're normally pretty quiet as you just sit there. Lastly, my understanding is that reciprocal inhibition is when the body momentarily relaxes an antagonist to allow the agonist to do its work - which in and of itself does not create weakness. In sum, while I certainly agree that many people have weak gluteus muscles (one or more of them) I can't get behind this explanation.
2. One author writes, DBS "can lead to lower back pain and hip pain, as well as knee and ankle issues, as the body tries to compensate for the imbalance." Can weakness lead to pain? Sure. Is it more likely, though, that the weak glutes, low back pain, hip pain, and lower extremity pain are all manifestations of one pathology? That is, most likely a lumbar spine that is a little, or a lot, malaligned? The words "compensate" and "imbalance" are actually my two least favorite words in the world of physical medicine. While it doesn't seem far-fetched to think, "Hey, my left knee has been hurting for awhile and now my right hip is starting to hurt because I'm walking differently," what if we instead asked: What can be causing both left knee pain and right hip pain? You must have a solid diagnosis first. The answer to that question, of course, is almost always the spine.

Another article states, "It may seem bizarre for a muscle to just stop functioning out of nowhere." Yes! It is indeed very bizarre! Except when you recall that nerves send power to muscles ... and when there is a problem with the flow of electricity through those nerves, muscles will stop functioning seemingly out of nowhere! This inhibition-driven weakness, while not normal, is extremely common. (In fact, if I tested the primary muscles of the upper and lower extremities of 100 people, I bet not one person would demonstrate full strength. That means not one person would have uninterrupted flow of electricity from their spine to their muscles.) The good news is, once you restore the flow of electrical power from the spine - I use specific movements with my patients to accomplish this - muscles should immediately regain normal strength.
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So what is going on with DBS? In the large majority of cases, prolonged sitting (the more slouched, the worse) creates a malalignment in the low back which impedes the flow of electricity via the nerves to the glutes, depriving them of their juice to be strong. The same scenario can create pain in the glutes as pinched nerves can carry pain along their path (or any altered sensation such as tingling or degrees of numbness). That'swhy your butt is dead. To fix it, you'll need to address your low back in order to decompress the nerves. And then, once the power is back on, if your gluteus muscle strength doesn't return completely since the muscles had been dead for so long, you can move on to targeted strengthening exercises to rebuild them. -- Laura