Weakness

Nerves may be damaged by two main processes:

• Direct compression or trauma of one or more “motor neurones,” the ones that send messages from the brain to the muscles to make them move, will result in weaker muscles that become progressively smaller and ineffectual.
• Medical conditions or diseases that directly affect the nerves. The commonest medical problem affecting the nerves is referred to as a neuropathy. This can affect all the nerves of the body including the motor nerves. There are specific disease processes such as motor neurone disease and multiple sclerosis that prevent the normal nerve transmission, the messages from brain to muscles, and weakness then results.

The categories are separated into direct trauma to the muscles where a laceration (significant cut) or tearing through the muscle can lead to scarring and permanent damage. Again there are medical problems that specifically affect the muscles including myositis, where the muscles become inflamed, or specific myopathies (weak muscles) of which there are several types that are diseases specifically reducing muscle function.

When we experience pain, two areas of the brain receive the pain message. The front of the brain is the processing area. This part thinks about the pain, what its cause may be, why it is persisting and what can be done about it. The subconscious part of the brain also receives a pain message and it will then send a message back to the muscle to do either one of two things:

• The subconscious will cause the muscle to tighten up and go into tension or spasm. This is a fairly primitive defence mechanism and a kind of self-imposed immobilisation. This basic response suggests that if we do not use the muscle and keep still then the painful problem will settle down, heal and go away. This is not always a helpful response from our brain since we still need to get up, move around and perform our daily activities. It results in a cycle of more pain, more pain messages to the brain, further reduction in muscle activity and spasm and so on.
• Having a learned experience of pain: For example, if by putting weight through our hip when walking upstairs provokes pain, our subconscious may then send a message to the muscles not allowing them to contract properly, as it anticipates a painful result. Since we are trying to move and the muscles around our hip do not contract in the usual way, then we will experience the sensation of “my leg giving way,” loss of balance and even falling over.

This is when simply not using any muscle or muscle group results in the muscle becoming smaller and therefore weaker. Naturally, any medical condition or trauma that imposes immobility for a period of time, will cause a certain degree of disuse atrophy as a consequence. It is also true that if we live sedentary lifestyles and do not perform any exercise then inevitably our muscles become smaller and therefore we will become generally weaker and more vulnerable to mechanical pain.