Your abdominal muscles (in the front of your trunk, not in your back) do the real work when it comes to sit-ups. Many structures are of course still involved with this exercise, though, as with any movement. When someone tells me that sit-ups hurt his back my thought is that repeated joint activity (flexion) causes his back pain. With sit-ups, the spinal joints flex, or bend forward. If repeated muscle activity was the problem causing the pain, we’d expect the pain to be in the abdomen, where the muscles actually are.

Location of pain and provoking factors are just two pieces of the puzzle when it comes to diagnosing, but they do tell me two important things. One, in this scenario the person likely has the diagnosis of joint derangement (versus a muscle or other problem). And, two, it’s unlikely the person will need spinal flexion to get better, since it is clearly provocative. (Thus it’s more likely he’ll need another spinal direction to get his joints working properly again - and therefore be able to soon tolerate all the flexion in sit-ups.) -- Laura

If a muscle is actually physiologically tight (versus feeling tight), it can only restrict movement when it is put on stretch/tension. So, if your left upper trap muscle in your neck feels tight and you’re missing left side bend but have normal motion into right side bend, the left upper trap muscle is not actually tight. A muscle like this on the left is put on slack with movement to the left and put on tension with movement to the right. Therefore, something ELSE - not the muscle - is the cause of the tightness feeling. That is, something ELSE is causing both the loss of motion in left side bend as well as the feeling of tightness in the left neck.
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In this scenario, it is most likely that a joint in the neck is not moving properly – and that is the issue, the cause, that needs to be addressed. Joints that are not moving well can cause loss of movement in one or more planes of movement and can cause local symptoms or referred symptoms in other areas. The term I use for this diagnosis is joint derangement. It is addressed primarily with movement in a specific direction.

Just to be clear, it is rare that a muscle is actually physically tight, especially for no apparent reason. It is common, however, for muscles to feel tight as the feeling is referred from nearby structures such as joints. We can determine if a muscle is actually tight vs feeling tight with a thorough evaluation; we don't have to guess. The most obvious example I can think of when a muscle is indeed actually tight is when there has been direct muscle injury. As it heals, the scar tissue will be tight, as is its nature. With appropriate progressive movement, the length will be regained. -- Laura

​My biceps is usually in quite a shortened position due to shoulder flexion and elbow flexion. Ditto for my neck flexors and hip flexors. But they’re not actually shortened (or tighter than normal). I have full flexibility in each of those muscle groups. Muscles can indeed become shortened, but it’s not a given they will get short if they spend most of their day like that.

Again, there are ways to test muscle length/flexibility. I don’t rely on muscle length/flexibility tests alone because they are not very specific. That is, when you test the flexibility of a muscle, you are also testing other structures. What I do if I suspect muscle shortening is perform the muscle length test and note the findings. Then I will do dynamic movement testing and assess the effect on the muscle length test when re-tested. If we rule out everything else, and the muscle stays tight, then we can diagnose muscle tightness.

But my distinct point here is that we can’t make an assumption based on daily positions or activities. If you think “hip flexors get tight” because they’re shortened all day, well then what about all the other muscles that are shortened all day? Isn’t it more likely that something else is going on in the hip area? Things can be figured out with competent testing - not assumptions. -- 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

It’s not uncommon that sleeping makes problems worse. That is, symptoms become exacerbated and/or movement becomes limited. Morning stiffness to a small extent is allowable when it comes to spinal flexion, but, otherwise, after being up and about for a few minutes, you should have the same amount of mobility you went to bed with.

During sleep, we often spend considerable time in one position without moving - whether we want to or not. It is my opinion that most orthopedic problems are related to movements and postures, so it makes sense that, just like with sitting or walking, sleeping postures can easily make people worse (or better).

If the thought process is that people need muscular strength to “hold” or “stabilize” joints in the right position, then there must be profound weakness if the simple act of sleeping causes joints to destabilize. Similarly, sleeping should not be aggressive enough to strain/pull muscles.

My thought process is this: I agree healthy joints should be able to withstand prolonged positions while sleeping, but I don’t think the answer is muscle-driven stability. And I don’t think muscles get pulled in our sleep. Benign positions like sitting or lying can indeed move joints - regardless of how much muscle is nearby. And these subtle changes can commonly cause symptoms. On the whole, strength is wonderful, but I believe we need to get the joint better first by moving the joint itself.

It’s true that spinal discs enlarge when we lie down to sleep, and that may be the sole factor why someone has more pain and/or less motion upon waking (vs related to any certain position). But even if that is the causative factor, then, again, I want to primarily address the disc (part of the joint) versus address the musculature around it. It’s also true that not all orthopedic problems are joint problems. Sleeping on a painful tendon can worsen symptoms, too. But most problems do have to do with joints - and addressing them effectively is important. -- Laura

There are muscles encasing our heads and faces. I think people actually understand the concept of referred pain (or non-local pain) when it comes to headaches - they just don’t know they do. Put another way, I don’t hear much about people massaging their head (cranial) muscles, rolling them, stretching them, or otherwise treating those various muscles.

Of course muscles in general can be the producers of symptoms, but it’s rare. I write about this extensively. Everyone loves to name and treat muscles, but, while important, they’re rarely the problem when it comes to orthopedic disorders.

People seem to intuitively comprehend that head pain or headaches can come about for a lot of reasons. Stress, dehydration, allergies, hunger, concussions, and illness to name a few. There are indeed musculoskeletal causes as well - just rarely the muscles. The joints in the neck and mid-back can refer pain (or any symptom) to the head. In rarer cases, the jaw joint can create local symptoms.
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If people can understand that their head can hurt not as a result of the muscles in the area and that their chests and arms can hurt due to a heart problem, then hopefully people can start to grasp that arm pain or leg pain is not necessarily due to arm or leg muscles. -- 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

​Depending on where a muscle originates and where it inserts, it can move the bones of your body in a specific way. It’s rare that a muscle even works in isolation. A certain muscle or muscle group may need to be a focus of rehab in the case of a problem, but there’s no hierarchy of prestige in the human body. (I’m not talking about the heart, diaphragm, etc.) Your psoas is not the key, nor is your core (a group of several muscles). No one muscle will ensure health or prevent injury.

​The relative importance of a muscle is circumstantial, based on what a particular individual’s needs are. For example, a shot putter, to improve performance, will focus on different muscles than a cyclist. Someone whose goal is to be able to get up easily from a low couch will have different needs as well. -- Laura