The effects of breath control on intra-abdominal pressure during lifting tasks

Study Design. This was a repeated measures study examining 11 asymptomatic subjects while performing dynamic lifting using various postures, loads, and breath control methods. Objectives. To examine the effects of breath control on magnitude and timing of intra-abdominal pressure during dynamic lifting. Summary of Background Data. Intra-abdominal pressure has been shown to increase consistently during static and dynamic lifting tasks. The relationship between breath control and intra-abdominal pressure during lifting is not clear. Methods. Eleven healthy subjects were tested using lifting trials consisting of two levels of posture and load and four levels of breath control ( natural breathing, inhalation-hold, exhalation-hold, inhalation-exhalation). Intraabdominal pressure was measured using a microtip pressure transducer placed within the stomach through the nose. Timing of intra-abdominal pressure was determined relative to lift-off of the weights. Repeated measures analysis of variance was used to determine the effect of breath control, posture, and load on intra-abdominal pressure magnitude and timing. Results. There was a significant effect of breath control ( P < 0.018) and load ( P < 0.002), but not of posture ( P < 0.434), on intra-abdominal pressure magnitude. The inhalation-hold form of breath control produced significantly greater peak intra-abdominal pressure than all other forms of breath control ( P < 0.000 for all comparisons). No other comparisons among levels of breath were significantly different. No significant main effects of breath control were found relative to intra-abdominal pressure timing. Conclusions. Breath control is a significant factor in the generation of intra-abdominal pressure magnitude during lifting tasks. The effects of respiration should be controlled in studies analyzing intra-abdominal pressure during lifting.