The multifidus: what research suggests, and what it doesn't.
The deep muscles alongside your spine come up often in back pain research. Here is what the evidence supports, and where it stops.
If you have had back pain for years, you have probably been examined several times. One structure that often comes up in research but rarely in conversation is the lumbar multifidus — a group of deep muscles running alongside the spine.
What it is
The multifidus is a deep, segmental muscle group along the length of the spine. In the lumbar region it contributes to control of individual vertebrae and tends to be active in anticipation of movement rather than only in response to it.
Studies have reported changes in these muscles in people with back pain. What that means for any one person is far less certain.
What research has reported
Studies including Hides and colleagues (1996) reported reduced multifidus size on the painful side after a first episode of acute back pain, which had not recovered when pain had settled weeks later. Imaging studies in people with long-standing pain have reported muscle changes such as atrophy or fatty infiltration. These are group-level findings, largely in specific study populations, and the link between muscle appearance, imaging, and symptoms is not straightforward.
Where the evidence stops
It is tempting to conclude that targeting these muscles is the missing answer. The evidence does not support that. Cochrane reviews have found motor control exercise to be broadly comparable to other forms of exercise for chronic nonspecific low back pain, and current guidelines recommend structured exercise as part of care without naming a best modality.
What that means in practice
Doing exercise consistently, progressing it gradually, and staying active are the parts most consistently supported. Deep trunk work is a reasonable component, not a proven cure. A longer program gives more time to progress gradually, but a 16-week length is a practical structure rather than a dose established by trials. Programs like this one, including ours, have not been tested in clinical trials, and individual responses vary — including people who do not improve. If your pain is severe, worsening, or accompanied by new neurological symptoms, see a clinician rather than a program.
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Read the evidence or review the draft.
The evidence page explains the research limits. The demo shows how those components are presented in the current review draft.