The multifidus muscle is a series of muscles that are attached to the spinal column providing it with stabilization, support, and relieving pressure off vertebral discs so that body weight is properly distributed along the spine.
Per a 2001 study found in the European Spine Journal: Back pain patients have a decreased ability to voluntarily activate the multifidus. This may be due to pain, pain avoidance, or deconditioning.
Thus, it’s very important to voluntarily recruit the multifidus, with all stabilization exercises, to maintain neutral spine and prevent further back injury.
The following is an example of a spine stabilization exercise with emphasis on the multifidus:
Swimming Prep on the Large Stability Ball
Starting position: Lay on your stomach over the Stability Ball with the pelvis and spine neutral. Place hands under shoulders. (You may need to place hands on a platform if the ball is too high.) Extend the knees, with hips slightly flexed, legs hip distance apart and toes tucked under.
Maintaining a neutral spine, exhale as you reach one arm overhead and lift the opposite leg off the mat extending the hip. Make sure abdominals stabilize the torso as you switch sides.
Repeat 8 -10 times each side.
Information gathered from www.merrithew.com and Danneels et. al. Differences in electromyographic activity in the multifidus muscle and iliocostalis lumborum between healthy subjects and patients with sub-acute and chronic low back pain. European Spine Journal. 2002; 11:13-19.