Individuals With Low Back Pain Breathe Differently Than Healthy Individuals During a Lifting Task

STUDY DESIGN: Case control, repeated-measures, experimental laboratory study. OBJECTIVE: To determine if, during a whole-body lifting task, individuals with low back pain (LBP) breathe differently than age-matched controls. BACKGROUND: Breath control may be optimized to provide increased intersegmental control of the lumbar spine through the generation of intra-abdominal pressure. Consequently, impairments in respiratory and trunk muscle coordination during lifting tasks may contribute to the occurrence or maintenance of LBP. METHODS: Participants without LBP (n = 30) were matched by gender and age with those presenting with chronic mechanical LBP (n = 32) of at least 1 year in duration. Participants completed a total of 8 self-paced lifts of a crate from the floor to a table, with the crate empty during 4 of the lifts and loaded to 25% of the participant's body weight during 4 of the lifts. The amount of volume in the lungs, measured as a percentage of the individual's vital capacity (%VC), was identified at 9 points during the lifting task. A 2 x 2 x 2 x 9 (group by gender by load by time) mixed-model analysis of covariance (ANCOVA), with age as the covariate, was used to identify differences among conditions and groups of %VC used during the lift. RESULTS: Individuals with LBP performed the lifting task with more volume in their lungs (48.2 %VC) than healthy peers (40.9 %VC). Age significantly affected %VC used during the lift: with increasing age, participants with LBP increased inspired volume and participants without LBP decreased inspired volume. CONCLUSIONS: Individuals with LBP performed a lifting task with more inhaled lung volume than individuals without LBP. These findings are consistent with the theoretical link between breath control, intra-abdominal pressure, and lumbar segmental control. J Orthop Sports Phys Ther 2011;41(3):141-148, Epub 4 January 2011. doi:10.2519/jospt.2011.3437