Question

Frank uses improper body position to lift a heavy box and strains the muscles in his lumbar region. which muscles are most likely to be involved in this injury?

Answer 1

Lumbar region refers to the lower back or lower spine.

important muscles of the lumbar spines are:
1) multifidus - stabilizes and rotates the lumbar spine
2) longissimus 
3) spinalis

lower back pain are caused by improper posture, compression fracture, muscle injuries, fractured vertebrae, spinal stenosis, osteoarthritis, herniated disc.