Golgi tendon organs are your friends. They are proprioceptors located in your muscle/tendon junctions and tell your brain how much strain is being placed on your muscles. Why do you care? Because without them, muscles would contract or release with with the same velocity whether you picked up a fork or a car!
Imagine picking up a forkful of food and having it come at your face with the same force that you use trying to lift up a car! You couldn't duck fast enough to get out of the way of the incoming tines and you'd probably shatter your hand on the table bringing the fork back down to your plate.
Proprioceptors are microscopic cells that give your brain information about what you're doing and how you're doing it. There are many kinds of proprioceptors and each do their own thing. Golgi tendon organs or GTO's monitor muscle activity at the muscle fiber level. They are positioned in series with muscle fibers in such a way that muscle goes into the organ and tendon comes out. GTO's don't actually connect muscle to tendon; they're just involved at that junction.
What you would want to know about GTO's is that they can be reset both automatically and manually. Notice, for instance, a weightlifter's arms. Even when the arms are relaxed, they appear flexed, bent at the elbow, as if they were hugging a redwood tree or something. This is because the contracted state of the muscles is such that there is constant tension on the arm flexors. GTO's reset automatically over time to stop telling the brain the muscle is contracted and, instead, that this muscle is normal and in a relaxed state. If, from that relaxed state, a weight was placed in the hand of the weightlifter, the muscles would stretch, the elbow would extend, and the GTO's would report the strain placed on the muscle even though the weight wasn't being lifted.
There are two types of contractions in muscles -- concentric, which is the muscle control you use when bringing a fork up to your mouth, and eccentric, which is the muscle control you use when lowering your fork back down to the plate. What's being reported in our weightlifter is an eccentric contraction.
Now, after the weightlifter lets go of that weight, the muscles automatically contract again and put that flex back into the elbow because the GTO's think that's where normal is. Of course, we all know that may be normal for apes, but not for humans. So when the weightlifter decides he doesn't want that flexion in the elbow anymore, he goes to his favorite massage therapist and they work on helping his arm relax the musculature crossing the elbow joint. They work on both the belly of the muscle where the contraction is taking place and at the junction where muscle becomes tendon...that's right, where the GTO's are located.
As his biceps brachii, flexor and extensor carpi radialis, brachialis and others cease contracting so much, the GTO locations are also worked. Eventually, if all is acceptable to the musculature, much less contractile tissue holds tenion in the muscle belly and the GTO's are manually reset. After several sessions, the weightlifter's arms hang more normally, even though there is still obviously tone in the arms.
So what does a weightlifter's ape-like problems have to do with you if you're not a weightlifter?
The same things happen to everybody. They may not seem so evident as our weightlifter's arms, but only because we get used to seeing ourselves daily. Then, one day, we notice perhaps in a store window reflection that our heads are craned forward on our neck. We never noticed that before...how did that happen? Well, maybe from spending too much time on the computer or leaning down looking at our text messages on the cell phone. Could be because we lie in bed reading with our heads propped up vertically on a pillow so we can see our books while the rest of our body lies horizontally.
Perhaps one shoulder is noticeably higher than the other. Maybe you walk with your toes pointed in or out. Could be you notice a big curve in your lower back that never used to be there. Or someone asks you why your hands are balled into a fist while you're just sitting and talking with them. You might bend over to tie your shoe or pick up the baby and feel a strain in the back of your legs.
All of these are the same kind of thing. There's a contraction going on in one or more (rarely is it just one) muscle that, over time, has accepted tension as normal. The GTO's in those muscles have reset themselves so the brain stops hearing your muscles complain about being tight. What to do?
Do the same that the weightlifter did and go to a good massage therapist. We're trained to work on releasing these muscles and resetting GTO's so your body will return to the way it's supposed to be. Muscles are supposed to be soft and supple and should never hurt when felt under pressure. If they do, you have contractions going on in there and your body needs help in letting that go.
There's another thing GTO's do -- they protect our muscles from dangerous overloading. Let's say you're standing at the store checkout counter and the bagger has placed all your heavy items into one bag, then they hand it to you. Your arm, back and pelvic structural muscles go into action, taking up the slack in your relaxed muscle state to immediately try to hold the load. If that load is too much, your golgi tendon organs will yell at your brain that there's too much weight and your muscles will never survive if they try to hold it. Your brain will instantly tell your muscles to release, relax and let go and that bag of heavy stuff will head for the deck. I hope your feet are quick!
Golgi tendon organ proprioceptors are ingenious little guys. They protect our muscles from overloading. They tell us how fast to bring that fork up to our mouths or how slow to lower a baby into a crib. They can set and reset themselves according to the conditions our bodies live in so our brains aren't bombarded with constant complaints of muscle pain. Sometimes, that's good and sometimes not. It makes us adaptable to varying conditions, but it can also render us out of balance.
See your massage therapist soon. Get that tension out and get those GTO's back to normal.
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