Sciatica can also be caused by pressure on the nerve due to a herniated or bulging disc. A herniation is when a disc protrudes out from between the vertebrae and this can either be caused by an event like a car accident, or by months or years of uneven pressure due to muscle imbalances.
Herniated discs are probably one of the most common diagnosis's for sciatica out there and this diagnosis is often used when a doctor can't find an explanation for the person's pain... similar to a doctor explaining away various aches and pains as arthritis.
Plus, research has shown that in many cases, people live with herniated discs yet never have any back pain or symptoms. The point is, if you've been diagnosed with a herniated or bulging disc, it may not be what's really causing your back pain! Even if you've had x-rays and MRI's done that show a herniated disc, chances are still very good that it's not the problem...
The problem is, even if you were diagnosed with a herniated disc, you have to understand that if you don't address what caused the disc to herniate in the first place, you'll likely struggle with back pain or sciatica for years.
Nearly Every Herniated Disk is the Result of Muscle Imbalances!
Above is a close up so you can see what happens to the spine when it's being pulled out of place. When your muscles pull your spine out of alignment, the uneven pressure and compression on your vertebrae wear down your discs much faster than normal. And it's very important to note that your discs are NOT designed to be subjected to this constant, uneven stress and that's why sooner or later they will begin to bulge or herniate.
Imbalances are problems which occur in muscle groups which work in opposing tasks due to over and under usage. Muscles are generally set up with one group needed to perform a given activity, such as bending your leg, and another group used for the opposing action, such as straightening your leg. Almost every bodily movement has an opposite movement possible, from the neck down to the toes. Muscular pairs which accomplish these opposing movements can work front to back or side to side (left and right) throughout the body.
Imbalances are thought to occur when one set of specific task musculature is overdeveloped, overstretched or overused, while the opposing (opposite task) muscles are underdeveloped, under stretched or underused. This can occur from normal day to day activities or from repetitive motion jobs and repetitive stress injury conditions.
When your muscles are out of balance they pull your bones and joints out of their normal position and this places your muscles, bones and joints under constant stress and uneven pressure...
For example, the position and curvature of your spine is determined by numerous muscles and whether they are balanced or not... There are over 640 muscles in the human body! Nearly every muscle in the body affects your spine and if just one of these muscles are out of balance you're in trouble...