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Best Low Back Posture for Lifting

What's better? Lifting with a flat or flexed back? There's still a lot of debate over the best posture to use when lifting heavy loads. In this study the effect of lumbar posture is measured on the muscles, ligaments, and internal loads of the low back.

Fifteen (15) healthy mean were tested using three different lumbar postures. Sometimes the subjects lifted with a flat back (kyphosis). At other times they were told to use a swayback (lordosis) position of the lower spine. In an equal number of trials they could lift however they wanted (freestyle).

Electrical signals from the muscles were recorded during each lift. They found the muscle force increased with lordosis when no load was carried in the hands. The opposite occurred when carrying a load. Changing the lumbar posture from lordosis to kyphosis had a greater effect on shear force compared to compression.

Overall the results of this study support using a freestyle method of lifting. Lifting with slight flexion of the low back is the second best choice. Using the swayback or lordosis position seems to increase muscle activity. Over time these muscles will get tired from repetitive or sustained loads. Greater muscle activity increases the risk of back injury.

References: Navid Arjmand, MSc, and Aboulfazl Shirazi-Adl, PhD. Biomechanics of Changes in Lumbar Posture in Static Lifting. In Spine. December 1, 2005. Vol. 30. No. 23. Pp. 2637-2648.

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