The effects of breath control on maximum force and IAP during a maximum isometric lifting task.

BACKGROUND: Evidence exists linking breath control to increases in intra-abdominal pressure and lumbar stability. Weight-lifting experts use this evidence as a rationale to suggest that increases in lumbar stability afforded by specific forms of breath control can influence the amount of force produced by the trunk. No studies have examined this issue. Therefore, this study determined whether voluntary control of the breath is related to maximal trunk extension force and if maximal force is correlated to intra-abdominal pressure.
METHODS: Thirteen men and 20 women (mean age: 25.6 years (5.5)) performed a maximal isometric trunk exertion in a knee bent posture using voluntary breath conditions: (1) inhalation prior to exertion with hold during exertion; (2) exhalation prior to exertion with hold during the exertion; (3) inhalation prior to the exertion with exhalation during the exertion. A subset of subjects (n=11) were also simultaneously measured for intra-abdominal pressure. Separate repeated measures ANOVA were used to determine the effects of breath conditions on force and intra-abdominal pressure. Pearson coefficients were used to determine the correlation between force and intra-abdominal pressure.
FINDINGS: Breath control did not significantly affect isometric force production (P=.089) but did affect intra-abdominal pressure (P=.003). Correlations between force and intra-abdominal pressure in each breath condition were low (range: 0.152-0.583).
INTERPRETATION: Although breath control was shown to influence intra-abdominal pressure, it does not appear to influence isometric trunk extension force in a knees bent position. Further, the intra-abdominal pressure produced in such efforts appears to be unrelated to the amount of force produced.