The effects of low back pain on natural breath control during a lowering task.

Preventative and rehabilitative efforts relative to low back pain (LBP) and manual material handling (MMH) are often directed toward proper technique. However, breath control may be an additional factor to consider. Optimizing breath control may provide increased segmental control of the spine through the production of increased intra-abdominal pressure. It has been found that breath control differs during the lifting phase of MMH for individuals with LBP. However, little is known about breath control during the lowering portion even though it accounts for 30% of MMH tasks. In this study, individuals with LBP (n = 32) and aged-matched healthy individuals (n = 30) lowered a crate from a table to the floor four times with the crate empty and four times with the crate loaded at 25% of body weight. The amount of volume in the lungs as a percentage of each individual's vital capacity (VC) was identified at nine points during the lowering task. Individuals with LBP completed the lowering task with significantly more volume in their lungs (45.9% VC) than healthy peers (40.9% VC). Further, with increasing age %VC significantly increased in those with LBP. Moreover, %VC significantly increased in response to the mechanical challenges introduced when lowering a load. These findings support the theoretical link between breath control and lumbar segmental control and provide preliminary evidence supporting rehabilitative efforts which add a focus on breath control for those with LBP.