Vibration of the spine and low back pain.

There are now many studies suggesting a positive relationship between both low back pain and spinal degeneration and exposure to whole body vibration. Such relationships appear to be particularly marked in drivers of tractors, earth-moving equipment, and trucks. There is a tendency toward a greater incidence of complaints as exposure increases. Vibration affects the spine by exciting a 4-6-Hz resonance that is related to the biologic "soft spring" between S-1 and the seat. The muscle nerves fire sequentially under vibration and fatigue. In animals, vibration exposure leads to pronounced creep, increased disk pressure, and changes in the levels of neuropeptides in the dorsal root ganglia.