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How muscles work - Part 1: why they hurt

Warning – this is going to get technical, although it will still be a rather simplistic explanation. If you don’t want a technical explanation then here is a simple one:

Magic. That’s it. Why else would the clinic be called Magic Hands?

OK so that might be too simple for some of you. Let’s fetch a cup of coffee and a biscuit and go on.

You know muscles, right? There are nearly 700 of them in the body and each one is designed to do a very specific thing. Even though that might be very similar to the specific thing the muscle next to it is designed to do, it’s still going to be something that only that particular muscle is really good at. If all your muscles are working really well then that’s great – you’re rocking. But as soon as one of them goes slightly wrong, you’ve got problems. You’re probably only consciously aware of fewer than 10% of the muscles in your body, unless you’ve made a real study of them, so there’s plenty of scope for them to go wrong without you really knowing it.

Let’s look first at how a muscle works. Muscles are made up of thousands and thousands of fibres called sarcomeres, which lie neatly alongside each other in each muscle cell. This is a picture of actual sarcomeres in an actual muscle cell (the gastrocnemius, specifically, which is the muscle that makes your lower leg bulgy at the back.) How awesome is that? They really are green, too, or at least they are in mice; this is a mouse’s muscle. Yours will be just the same, because cells are the same in all animals; what makes elephants bigger than mice is not the size of their cells but the number of them.

Sarcomeres are made up of two protein filaments, actin and myosin. Myosin filaments are quite thick (relatively speaking) while actin is spindly. When a muscle contracts the sarcomeres don’t change length, but the actin fibres do; as they are fastened to bits in the muscle called z-lines, they pull the z-lines closer together which makes the muscle shorter. The actual sarcomere stays the same length though – clever huh? If you imagine you’re standing between two boxes with ropes attached to them and you’re pulling on the ropes to move the boxes towards you, that’s a good way of visualising what’s happening in the muscle. You’re the myosin, staying just the same shape and size as you always were; the ropes are the actin pulling the boxes – the z-lines – together. Overall the amount of space you and the boxes take up will reduce as they get closer to you, but neither they nor you have got any smaller.

In order to make the muscle contract you need a chemical called ATP, which your cells generate all by themselves out of oxygen, glucose and a bunch of other stuff that happens to be lying around. (That’s why you get out of breath when you exercise, because your cells need more oxygen to make the ATP so your muscles can work). What ATP actually does is prevent the actin and myosin from sticking to each other. If they stuck, it stands to reason that the actin wouldn’t be able to pull the z-lines together to contract the muscle. Imagine if you couldn’t move your hands along the ropes attached to the boxes you’re pulling. No matter how hard you pull, the boxes are only going to move a small amount before you run out of arm length.

In order to make ATP the cells need oxygen and the oxygen gets to them via the blood. As you probably know, blood visits the lungs to soak up a nice healthy load of oxygen, trundles round the body via the heart dropping off parcels of oxygen to all the bits that need it (i.e. all of them) and picking up the trash of carbon dioxide before going back to the lungs to swap it for another load of oxygen. Circulation of the blood is therefore vital to being able to move.

And now we’re getting closer to Bowen therapy and further from advanced biology. You’ve heard of blood vessels, but you may not know that they’re suspended in a semi-liquid called fascia. It’s a bit like jelly. If it’s warm and moist it’s almost liquid but the reason you buy jelly in lumps and not bottles is because when it isn’t warm and moist, it’s pretty solid. You can tear jelly easily. It doesn’t take much stretch of the imagination to picture your blood vessels trying to run through a bowl of jelly. They won’t have an easy time of it. So your blood flows more sluggishly, the deliveries of oxygen get behind and the poor muscles can’t generate the ATP they need to move. You move less and more slowly, which would be fine if it wasn’t for the fact that the fascia relies on your moving to keep it nice and soft and pliable. The less you move, the less you’re able to move. You’ll be familiar with that – when you’ve been sitting still for a long time, or when you get up in the morning, you’re stiffer and it’s easy to go ‘ouch’ when you do move.

This is what happens when healthy muscles get behind on their deliveries of oxygen and ATP. When you try to carry on moving as though everything was normal, your muscles are overworked. It might not feel like it but they are. An overworked muscle is basically one that’s doing more work than it’s capable of; and what it’s capable of will vary according to how much blood, oxygen and ATP are available. Remember some of these muscles are only designed to make tiny movements in the first place. You have two sets of muscles; postural and motor. Postural muscles hold your body in place, making sure your legs and arms don’t fall off and that your organs all stay where they should be. Motor muscles are the ones you’re more familiar with, the ones that let you move and run and lift things. You’ll notice when you injure a motor muscle, but probably not when you injure a postural one. However both sets work in the same way.

Here are some muscles. You may think it looks a bit like a raw steak, and that's because that's what raw steak is - muscle tissue.

Muscle tissue - skeletal muscle

I mentioned earlier how specialised muscles are, but they’re also great teamworkers. If a postural muscle – say one that holds your shoulder joint together – gets overworked then its companions in the area will help it out whether they’re postural or not. That’s not an issue for a short time, but after a while the helper muscles get overworked too – remember they’re doing something they’re not designed for. Once a muscle is being made to contract more often than it should it goes into a state called tetanus (yes, like the disease). That means it doesn’t relax. That’s like holding something up in the air for hours – it’s easy at first, but it soon gets jolly difficult and you are very glad to put it down.

Overworked muscles don’t just get tired. Remember ATP? An overworked muscle needs more of it and the only way it can get it is to demand more oxygen and more glucose. Making ATP produces waste products, specifically pyruvic acid; under normal circumstances with plenty of oxygen that gets converted into more ATP. If there isn’t enough oxygen though, the pyruvic acid gets turned into lactic acid, which you may have heard of; it’s what makes your muscles burn when you do more exercise than you’re used to. Lactic acid just hangs around unless there’s a good blood supply to wash it away – but there isn’t, because you’ve got reduced circulation due to the stiffened fascia. You can see where we’re heading with this. Lactic acid build up isn’t good for you; it blocks the circulation of healthy fluids and ends up forming what’s scientifically known as trigger points. The unscientific name for them is ‘painful’. That reduces the circulation and stiffens the fascia even more, and the cycle becomes more vicious.

Enter the Bowen therapist, ideally me. Although other Bowen therapists may be able to do this too. We’ll cover their role in the next episode of this blog.

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