Previously, I have discussed various sources of low back pain (LBP) and that often, the wrong muscles are blamed for the pain. One of the main reasons treatment for LBP is frequently unsuccessful is that the source of pain is misdiagnosed. Often the culprit is not even a “back muscle”–which renders most back pain treatments (TENS, ultrasound, acupuncture, manipulations, heat/ice, etc.) minimally effective (at best).
If your back hurts when you try to straighten your spine/stand up, and you have no pain/numbness in your leg, hip flexors muscles are probably to blame. Hip flexors are a group of muscles that allow you to lift your knees and bend at the waist. Found deep in the abdominal cavity, they are some of the strongest muscles in the body.
Because of their location, they are inaccessible to palpation, and are too deep for ice/heat or TENS to be effective. Sitting relaxes/shortens the hip flexors. Standing stretches them, and if they happen to be in spasm, will cause immediate pain. Because hip flexors are very strong (important muscles for standing and walking), when they are in spasm, it is difficult to stand up straight. Also, hip flexor muscle spasms frequently cause neighboring muscles (quadratus lumborum, piriformis) to spasm.
Effective treatment involves light repetitive activity such as walking, elliptical, (upright stationary) biking, and stretching. When stretching the hip flexors, it is important to isolate the muscles (do not involve other muscles such as the quads or abdominals). A gentle, prolonged (a minute or more) stretch is the most effective way to reduce a muscle spasm—especially when ice application is not appropriate. Stretching should be done often (3-8 times a day) until spasm resolves. Also, avoiding activities/positions that promote the muscle spasms (sitting) need to be avoided, or recovery will be delayed.
Finding the source of LBP is essential to quick effective treatment. Treatment targeting low back/paraspinal muscles may be a waste of time/money.