Have you ever tried rubbing your muscles when they are sore and painful, and all of a sudden you don’t feel as much pain? We will take a look at one of the mechanisms today.
There are different kinds of nerves in our body. Some are responsible for sensing noxious stimuli, some are responsible for sensing pressure, and so on. The nerve responsible for sensing noxious stimuli is called the C fiber, while the one responsible for sensing pressure is called the A-beta fiber. The reason why rubbing the muscles reduces pain is mainly about the interaction of these two nerves at the gate of pain signals transmission. This theory is called the gate control theory of pain.
The gate control theory means that there is a gate mechanism in the way our brain transmits noxious information. Opening the gate allows pain messages to be sent to the brain; conversely, closing the gate prevents the message from reaching the brain. The C fiber opens the gate when there is a noxious stimulus, however, the A-beta nerve will close that gate upon mechanical stimulus such as rubbing, so we feel less pain.
Here is an example:
When we hit a hard object, damage to the skin or subcutaneous tissue stimulates the C fiber, which in turn opens the gates and sends pain messages to the brain, making us feel pain.
When rubbing the affected area with your hands, this stimulates the sensory nerves or the A-beta fiber, and it sends messages to the spinal cord that closes the gate, preventing the pain messages from the injury site from being sent to the brain, making us feel less pain.
This may explain why rubbing the muscles and various physical therapy can reduce pain.