Many of us have heard of the "rotator cuff" of the shoulder, but don't actually know what that means. You might have the vague sense it has to do with structures that control the shoulder, and you'd be right. It's the muscles that control your shoulder rotation! Since I get this question a lot, let's go ahead and break down the muscles of the rotator cuff in today's blog post.
The rotator cuff is made up of four muscles. They work to help the shoulder move, but are also crucial to stability of the shoulder. The shoulder joint is very mobile, it has great range (ideally), but the trade-off for that range is that it's fairly unstable compared to other joints. The muscles of the rotator cuff offer a Goldilocks situation- if they are too tight they can limit the range of motion of the shoulder, and if they are too loose then the shoulder is less stable. Creating a balance in the rotator cuff is important for the joint and to keep the nerve connecting well down the arm and into the hand. As a general recommendation, some moderate exercise for the rotator cuff is useful for those who do not experience pain in the shoulder, and exercises can be customized for those who do experience pain by a physiotherapist.
For those who like to know the names of the muscles they are:
External rotation: these muscles rotate the arm away from the center of the body
Several trigger points are common for the rotator cuff. They can cause sensations to the middle of the back, to the neck, and even tingling and numbness down the arm.
There are several resources for self-massage to help alleviate some of the symptoms of trigger points in the rotator cuff. Check out this detailed explanation for the infraspinatus. On the same site, you can learn to work your teres minor, as well as your subscapularis which is more difficult to do yourself.
There are several types of tears that happen in the rotator cuff as well, it's not just one injury when you hear "torn rotator cuff". You can read more about it here.
There's an old die-hard myth that just won't rest... the notion that eating fats make you fat. It's not so!
Dietary fat and the stored fat in your body, or "adipose tissue" (composed of fatty acids) are different! Actually, diets with a healthy amount of fats provide some health benefits. One analysis(1) found that those with low-fat diets had a higher likelihood of heart attack or heart disease. Another trial(2) found that participants on a low-fat diet lost very little weight, if any. Some fats are good, some are bad, and some are actually very important for the body to function!(3)
According to the Harvard Medical School blog(4) on healthy fats, the good kind can be found in vegetables, nuts, seeds, and fish.
Interestingly, a study in Food and Nutritional Research found that higher intake of refined carbohydrates (sugar) predicted a larger increase in waist size. This means sugar is more likely to make you fat than eating fat! (Well, actually, it all comes down to how many calories you consume. But I digress...)
A good overview of this diet can be found at this Business Insider page(5).
Diet advice is definitely tricky business, but this one is pretty clear at this point: eating fats is not the same as storing fat.
There is a lot more going on in your body, some of which I will cover in a later post. But it all comes down to how much energy you are consuming compared to how much energy you are expending.
This little table makes it very clear: fats have more calories per gram.
What this essentially means to you is that you will get full on them faster, so you don't have to eat as much. In other words, carbs sneak up on you, you don't "feel" how much energy you are eating- and then storing.
A great overview of the "calories-in calories-out" story (the discussion of energy from food converted to usable energy) is illustrated over at Physiqonomics in an entertaining format (some off-color language), and if you are interested in how the body takes care of stored fat, a free textbook resource can be read here if you like getting into the technical stuff.
Remember before modifying your diet, always check with your doctor and dietician first!
Why do my muscles hurt after exertion? Is that normal?
This post is here to tell you that yes, muscle soreness is totally normal after exercise. It usually peaks a day or two after exercise, and then fades off after about 72 hours. There are a lot of ideas about why it happens, and what you can do about it. Not everything you may have heard is accurate, though. But let’s go over the basics here.
Delayed Onset Muscle Soreness (DOMS) (1) is generally a painful response to new activity. Whether lifting something heavier than normal, using muscles you haven't used in a long time, or doing more repetitions than normal, the pain comes from micro-trauma, or small tears that occur in the muscle during normal exercise. These micro-tears are necessary for the muscle to grow(2).
It's not just the micro-damage, but there is also a response in the nerve signals to repair the muscle stronger than it was before (3), but also to grow new nerves (4). The combination is most likely to result in pain. One very interesting study found that pain occurred even in a muscle group that was not exercised, which suggests a neural component of the pain associated with DOMS (5).
The way muscle gets damages is mainly by eccentric contraction, which is the lengthening of the muscle while under stress (6),(7).
It was once thought that lactic acid buildup in the muscle was the cause of the pain after exercise, but this has been demonstrated to be false (8), (9). Your lactate actually clears out of your system pretty quickly compared to how long you are sore.
The good news is that as you adapt to the new movement or exercise, your body actually builds support in the area you are exercising! (10) That's kind of amazing if you think about it... You have tiny little workers running around reinforcing the areas of your body that you are using, and conserving resources in areas you aren't using.
Is there any way to avoid the muscle soreness that accompanies exercise? Well, the first thing I always say is that if it works for you, then do it. But as far as the studies tell us, there's really no significant way to avoid it. You'll be sore, but you will adapt, and you will become stronger and more stable, with lasting benefits for years to come.
In terms of research, stretching before and after did not significantly reduce muscle soreness (11). While you do want to stay hydrated, it may not be accurate to say that increasing your water intake will lead to less cramping or pain (12). In sprinters, the delayed onset of pain did not respond to anti-inflammatory drugs (13) and anyway it doesn't appear that inflammation is a necessary component to the adaptations that occur in muscles after exercise (14).
Interestingly enough, it seems that there is a way to temporarily reduce the pain that occurs after exercise: to exercise some more (15), (16), so long as it is intense enough.
Massage therapy was found to be effective for some people in reducing some of the symptoms of muscle damage (16).
Other treatment ideas may have lower success in studies, but if it makes you feel better then by all means, do it! You could try heating, icing, or a combination of the two!
There are many factors that could lead to a slower recovery from exercise, and some people may experience more pain than others. For example, low Vitamin D levels are related to widespread pain (17), (18), (19), (20), and even muscle weakness (21).
There is still a lot to learn about how pain works, and how we can deal with it. I hope this gives you a little introduction to what's happening in the muscles, and maybe leaves you with in awe at how fascinating the body is!
“What are Trigger points?”
The introductory version.
Have you ever felt a pinch in a muscle, or a spasm that sent a feeling like a jolt or searing pain? Maybe it felt like you were unable to rotate your head like you should, perhaps you couldn’t reach back with your arm as far as you normally would, or even bend over to pick up something. Well, there are actually many things that could be causing this pain, but today I’m going to break down just one of those many possible causes. Today I’m going to talk about pain originating from a muscle.
Now, pain doesn’t come from muscles, it comes from nerves. That’s the signal system the body uses to convey the things you feel, through a variety of receptors. But when I say pain from a muscle origin, I mean skeletal muscle, not pain coming from two bones pinching a nerve, or from your stomach being irritated.
How does a muscle cause pain? This warrants its own post (coming soon™), but to summarize: in many ways. You don’t have to pull a muscle for it to hurt. You can underuse a muscle and it can cause pain- yes that’s right, you can sit around all day and that could lead to your muscles becoming atrophied or “shorter”, causing pressure to be placed on a nerve. It could be from dehydration, or even a lack of some dietary minerals. It can come from a lack of blood flow getting through to deliver important nutrients. It could be a sudden intense event, or doing one movement many times (overuse injury). It could come from sleeping on it funny, from twisting in a way its not used to… whatever the reason, your muscle can get little “knots” that feel very sensitive. Some of these knots are called “trigger points” and the resulting pain is called “myofascial pain syndrome”.
The painful areas may not necessarily be where the trigger point is. For example you may feel pain or numbness in the hand, but the tight muscle might be in the neck or shoulder. The hand would be considered a “referral zone”. There are many of these zones, where pain is referred, and a therapist who studies trigger point therapy learns many of these patterns.
Why don’t I just ignore my pain and carry on?
Well, there is a certain amount of “tough it out” that is good for you. On the other hand, there are reasons that your body is telling you it’s in pain. Mechanisms kick in that cause your balance to shift, your mobility to change, and these compensation habits can have lasting effects. Some are subtle, but for an obvious example, let’s say your knee is hurting and you shift your weight to the opposite leg. Over time, your weight to the leg that feels fine, and you begin to build stronger muscle on only that side. Perhaps your lower back may start to ache, as the rest of your body stabilizes itself to keep you upright. You could further extrapolate from here that your shoulders might then be affected, and your neck, and who knows maybe even your brain becomes lopsided (probably not)… but it may be sufficient to say that small adjustments over time can lead to imbalances that could have been prevented. You can work on your trigger points at home or with a massage therapist.
The actual mechanisms behind trigger points (what causes them) is a fascinating and debated topic that I will cover in later posts.
What's going on with me, research articles, interesting little blurbs. This blog is an attempt to consolidate research into an easily digestible format.
Alex Moon has been a Licensed Massage Therapist since 2012, did his undergraduate studies at Utah State, and is currently working on his Doctorate in Physical Therapy.