Lumbar spine postures in Marines during simulated operational positions

Area of Science:

• Orthopaedic Research
• Biomechanics
• Military Medicine

Background:

• Low back pain (LBP) is more prevalent in military personnel due to operational demands.
• Previous research focused on standing postures; other operational positions' effects on lumbar spine are less understood.

Purpose of the Study:

• To analyze the impact of simulated military operational positions and loading on lumbar spine posture in active duty male US Marines.
• To investigate if intervertebral disc degeneration and LBP influence these postures.

Main Methods:

• Magnetic resonance imaging (MRI) was used on an upright scanner.
• Measurements included global (lumbosacral flexion, sacral slope, lordosis) and local (intervertebral angles/distances) lumbar spine parameters.
• Evaluated positions: standing (no load, with body armor), sitting (with body armor), and prone on elbows (with body armor).

Main Results:

• Sitting decreased lumbar lordosis across most spinal levels.
• Prone on elbows significantly increased lordosis specifically at L5-S1.
• Marines with disc degeneration or LBP history exhibited reduced lumbar range of motion and extension compared to healthy individuals.

Conclusions:

• Simulated military operational postures induce characteristic postural changes in male Marines.
• These posture alterations, especially in those with pathology, may negatively affect functional performance.