Plowman, Sharon A.
M.S. Ed. (Master of Education)
Department of Physical Education
The lower lumbar vertebrae of rowers are subjected to high levels of shear and compression at mid-drive during the rowing stroke, and these forces may be partially neutralized by increasing intra-abdominal pressure (IAP). Since IAP fluctuates with ventilation, the purpose of this study was to compare the IAP response between two breathing patterns, inspiring during the drive and expiring during the drive, to determine if one breathing pattern might increase the IAP at mid-drive more than the other. Ten moderately active volunteers (5M, 5F; age: 25.1 yr ± 2.9; Ht: 176.4 cm ± 6.6; Wt: 73.6 kg ± 12.3) with and without rowing experience performed two sets (inspiration and expiration) of five 2-minute intervals on a Concept II rowing ergometer. The intervals began at a workload of 100 watts (W) and increased to 200 W by increments of 25 W. IAP was measured every .032 s for 30 s during each interval using a pressure transducer catheter. A position sensor was attached to the seat of the ergometer and interfaced with the data acquisition program so that the IAP responses could be expressed relative to the position of the body during the drive. Statistical analyses were completed using a 2 x 5 (breathing pattern by workload) repeated measures analysis of variance with Tukey or dependent 1-test follow-ups. There was no interaction between breathing pattern and workload for the dependent variables minimum IAP (IAPmin), maximum IAP (IAPmax) or change in IAP (?IAP) (p>.05); however, there was a significant interaction for middrive IAP (M-D IAP), with M-D IAP increasing at a greater rate as workload increased while expiring during the drive than inspiring during the drive (p<.05). When collapsed across breathing patterns, a significant difference in IAPmin, IAPmax, ?IAP and M-DIAP occurred as workload increased (p<.05). When collapsed across workload, a significant difference occurred in IAPmin and M-D IAP between the two breathing patterns (p<.05), but there was no difference in either IAPmax or ?IAP (p>.05). The data show that expiring during the drive offers more protection to the lower lumbar vertebrae at middrive than inspiring during the drive.
Manning, Timothy S., "Intra-abdominal pressure and rowing : the effects of inspiring versus expiring during the drive" (1998). Graduate Research Theses & Dissertations. 3627.
vii, 91 pages
Northern Illinois University
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