Lower crossed syndrome - tight muscles. Which muscles commonly demonstrate adaptive shortening in lower crossed syndrome?

• A. Iliopsoas, rectus femoris, erector spinae, and thoracolumbar extensors.
• B. Transversus abdominis and internal obliques.
• C. Gluteus maximus and gluteus medius.
• D. Latissimus dorsi and pec major.

Answer: (A)

In lower crossed syndrome, the body develops an imbalance where some muscles shorten (become tight) while others lengthen (become weak). The tight group in this pattern are the hip flexors and the spinal extensors. The iliopsoas and rectus femoris are chronically shortened from activities like sitting for long periods; they pull the pelvis into an anterior tilt, which increases lumbar lordosis. The erector spinae and thoracolumbar extensors are also kept tight as they continuously work to maintain an upright, extended spine against that anterior tilt.

Understanding this helps explain why the opposite muscles—such as the abdominal deep stabilizers (transversus abdominis and internal obliques) and the gluteal muscles (gluteus maximus and gluteus medius)—tend to be lengthened and weak, reinforcing the imbalance. Latissimus dorsi and pec major aren’t the classic tight muscles in this pattern, though they can contribute to other postural issues.