Why Back Pain Changes How Your Core Muscles Fire

Written by Ifije Ohiorhenuan, MD, PhD — Board-Certified Spine Surgeon. Last updated 2026-06-20.

It is not only about strength

When people think about core problems, they think “weak muscles.” But a major theme in back pain research is timing and control, not just strength. In healthy movement, the deep trunk muscles activate slightly before you move a limb — a feedforward “bracing” that protects the spine. In many people with low back pain, that anticipatory control is disrupted.

This is why a strong-looking person can still have a poorly controlled back, and why the goal of rehabilitation is often better coordination, not just bigger muscles.

What changes with pain

Research on the neuromuscular side of back pain points to a few recurring findings:

Pain is associated with delayed activation timing of the transversus abdominis — the deep muscle tends to switch on later than it should. (Effects on the amount of activation, and on other trunk muscles, are more variable.)^[1, 2]
In chronic back pain, the brain’s map of the trunk muscles can change — the cortical representations of the multifidus and transversus abdominis become less distinct than in pain-free people.^[3, 4]

In plain terms: back pain is partly a control problem, involving both the muscles and the nervous system that drives them.

Can exercise retrain control?

To a degree, yes. Motor control and stabilization exercises can partially normalize these deficits. One line of research found that sling-based exercise helped restore more distinct brain representations of the deep trunk muscles, alongside reductions in pain and disability.^[3, 4]

But — and this is the recurring honesty in this field — clinical improvement does not always match neuromuscular change. Motor control exercise is more effective than minimal intervention for pain, yet it does not clearly outperform other active exercise or manual therapy, and abdominal muscle onset timing can remain largely unchanged even after 8 weeks of exercise.^{[5, 6, 7, 8]} Some studies find people get better without the expected change in muscle timing, while others report only moderate correlations between improved recruitment and reduced disability.^{[9, 10, 11]}

What this means for your rehab

A few practical implications:

Control drills have a purpose beyond strength: they retrain coordination and confidence.
You do not need perfect “activation” to improve. If your timing does not normalize on a test but your pain and function improve, that still counts as success.
Quality over grind. Slow, controlled, well-coordinated movement is often more valuable than maximal effort early on.

Bottom line

Low back pain involves altered timing and control of the deep trunk muscles, and changes in how the brain represents them — not just weakness. Exercise can partly retrain this control, but improvements in symptoms and measurable neuromuscular changes do not always go together. Train control, not just power, and judge success by how you function.

References

This guide draws on the following studies and reviews. Much of this literature is observational or abstract-level, and several findings are mixed, so they are described here as associations rather than proof. The numbered markers in the text show which sources support each point.

Massé-Alarie H, Flamand VH, Moffet H, et al. Corticomotor control of deep abdominal muscles in chronic low back pain and anticipatory postural adjustments. Exp Brain Res. 2012;218(1):99-109.
Suehiro T, Ishida H, Kobara K, et al. Altered trunk muscle recruitment patterns during lifting in individuals in remission from recurrent low back pain. J Electromyogr Kinesiol. 2018;39:128-133.
Li X, Liu H, Ge L, et al. Cortical Representations of Transversus Abdominis and Multifidus Muscles Were Discrete in Patients with Chronic Low Back Pain: Evidence Elicited by TMS. Neural Plast. 2021;2021:6666024.
Li X, Zhang H, Lo WLA, et al. Sling Exercise Can Drive Cortical Representation of the Transversus Abdominis and Multifidus Muscles in Patients With Chronic Low Back Pain. Front Neurol. 2022;13:904002.
Macedo LG, Maher CG, Latimer J, et al. Motor control exercise for persistent, nonspecific low back pain: a systematic review. Phys Ther. 2009;89(1):9-25.
Saragiotto BT, Maher CG, Yamato TP, et al. Motor Control Exercise for Nonspecific Low Back Pain: A Cochrane Review. Spine (Phila Pa 1976). 2016;41(16):1284-1295.
Vasseljen O, Unsgaard-Tøndel M, Westad C, et al. Effect of core stability exercises on feed-forward activation of deep abdominal muscles in chronic low back pain: a randomized controlled trial. Spine (Phila Pa 1976). 2012;37(13):1101-8.
Unsgaard-Tøndel M, Fladmark AM, Salvesen Ø, et al. Motor control exercises, sling exercises, and general exercises for patients with chronic low back pain: a randomized controlled trial with 1-year follow-up. Phys Ther. 2010;90(10):1426-40.
Mannion AF, Caporaso F, Pulkovski N, et al. Spine stabilisation exercises in the treatment of chronic low back pain: a good clinical outcome is not associated with improved abdominal muscle function. Eur Spine J. 2012;21(7):1301-10.
Ferreira PH, Ferreira ML, Maher CG, et al. Changes in recruitment of transversus abdominis correlate with disability in people with chronic low back pain. Br J Sports Med. 2010;44(16):1166-72.
Unsgaard-Tøndel M, Lund Nilsen TI, Magnussen J, et al. Is activation of transversus abdominis and obliquus internus abdominis associated with long-term changes in chronic low back pain? A prospective study with 1-year follow-up. Br J Sports Med. 2012;46(10):729-34.