Muscle contraction

Cases studies Activation of pain transmission nerves Muscle contraction Inflammation Nerve root compression

Muscle contracture consists of a persistent and involuntary muscle shortening. It may be the cause or consequence of back pain.

Muscle contracture as Cause of Back Pain

Contracture occurs when the muscle is required to work above its ability, either intensely or repeatedly. Causes can include excessive effort or a less intense but perpetuated effort, e.g. maintaining a faulty posture for hours. On the other hand, some spinal anomalies or imbalance in back muscle strength may cause a muscular group to be required to work more than necessary, predisposing it to contracture. In this case, it is essential to perform appropiate exercises to compensate for this tendency and avoid crisis repetition.

Muscle contracture causes back pain through different processes

The contracture of a muscle directly activates pain nerves within the muscle, producing back pain.

The contracted muscle may compress an artery, decreasing blood flow to the area. This creates a vicious circle because a muscle with less blood circulation tends to contract more easily, and less than normal blood volume also activates pain nerves.

If this situation is perpetuated during a prolonged period of time or is repeated frequently, the muscle contracts more and more easily. In this situation, physical exercise is mandatory to stop this tendency.

Muscle contracture as a Consequence of Back Pain

Independent of its origins, back pain itself may cause muscle contracture by a reflex process.

In these cases, muscle contracture is not the primary cause of pain, but is an added factor that may exacerbate it. It can also make some of its causes worse. For example, in a painful disc herniation, muscle contracture may increase the compression exerted on the disc and facilitate the exit of the nucleus pulposus even more.