One of the most common questions I get is whether kidney belts are useful to reduce back pain particularly in forklift or truck drivers and people handling goods.

It’s a good question.  I often think of the image of the weight lifter with his kidney belt.  They must know something?

To simplify the science, a lot of lower back pain can be contributed to spinal tissue failure from prolonged or recurrent high compression or shear forces through the spine that occur when:

1. Lifting heavy weights
2. Lifting lighter weights using poor posture e.g. with arms stretched out in front  (functionally increasing spinal compression and shear forces) or with high repetition.
3. Sustaining postures that reduce the lumbar curve (such as bending or slouch sitting)
4. Being exposed to whole body vibration through sitting in a vehicle for more than 3 hours per day.

(1-4).

Is there anyway that we can reduce this spinal loading without changing our handling techniques?

Yes: if you hold your breathe for a few seconds, this raises the pressures in your abdominal cavity which  reduces spinal loading by relaxing the spinal muscles (the back muscles increase spinal loading when they work) (5-7).  However, you can’t hold your breathe forever and this advantage is lost.  So not really a workable solution.

What about kidney belts? Research found that kidney belts can slightly lower spinal muscle contractions (8-11%) and limit the amount of forward bending during lifting and encourage squat lifting, therefore reducing spinal loading in this scenario (6), however,  kidney belts tended to increase spinal muscle contractions in forklift drivers and make them more likely to experience back pain than forklift drivers who didn’t wear them (6,8).

References:

1. Chaffin DB, Park KS (1973). A longitudinal study of low-back pain as associated with occupational weight lifting factors. Am Ind Hyg Assoc J. 34(12):513-25
2. Freivalds A, Chaffin DB, Garg A, Lee KS (1984). A dynamic biomechanical evaluation of lifting maximum acceptable loads. J Biomech. 17(4):251-62.

3. Adams MA, McNally SD, Chinn H, Dolan P (1994). Posture and the compressive strength of the lumbar spine. J Biom. 27(6):791-791.

4. Nachemson AL (1981). Disc pressure measurements. Spine. 6(1):93-7.

5. Arjmand, N.; Shirazi-Adl, A. (2006). Role of intra-abdominal pressure in the unloading and stabilization of the human spine during static lifting tasks. European Spine Journal. 15:1265–1275.
6. McGill, S. M.; Norman, R. W.; Sharratt, M. T. (1990). The effect of an abdominal belt on trunk muscle activity and intraabdominal pressure during squat lifts. Ergonomics. 33:147-160.
7. Daggfeldt K, Thorstensson A (1997). The role of intra-abdominal pressure in spinal unloading. J Biomech. 30:1149–1155.
8. McGill SM, Norman RW, Sharratt MT (1990). The effect of an abdominal belt on trunk muscle activity and intra-abdominal pressure during squat lifts. Ergonomics. 33:147–60.