Authors: Andrew D Ray David R Pendergast Claes E G Lundgren
Publish Date: 2009/11/20
Volume: 108, Issue: 4, Pages: 811-820
Abstract
Resistance respiratory muscle training RRMT increases respiratory muscle and swimming performance at depths down to 17 msw It is unknown if RRMT improves swimming performance at greater depths and if the improvements are associated with a reduced work of breathing WOB altered respiratory mechanics and/or improved respiratory muscle performance Eight male subjects 303 ± 60 years were tested swimming underwater in a hyperbaric chamber at 37 m of depth against a predetermined load 70 dotV textO 2 until exhausted End expiratory lung volume EELV was determined by subtracting inspiratory capacity from total lung capacity throughout the swims The mechanical WOB on the lung was calculated as the integrated product of the transpulmonary pressure and ventilatory flow Maximal expiratory P EMAX and inspiratory pressures P IMAX were measured pre and postRRMT RRMT was performed every 30 s against spring loaded inspiratory and expiratory valves 30 min/day 5 days/week for 4 weeks RRMT increased P IMAX and P EMAX by 40 110 ± 11 cmH2O SD vs 155 ± 22 p 0001 and 30 148 ± 33 cmH2O vs 192 ± 49 p 0001 respectively respiratory endurance by 75 197 ± 154 min vs 344 ± 273 p = 0010 and swimming endurance by 87 264 ± 97 min vs 494 ± 216 p = 0004 The longer swimming time was associated with reduced dotV textE and dotV textA p 0001 f b p 0001 dotV textCO 2 p 0001 and WOB p 0001 There were no changes in EELV postRRMT These results suggest the improved exercise performance postRRMT was associated with stronger respiratory muscles a decreased f b and a reduced WOBThis work was supported in part by grants from the United States Navy NAVSEA N6133103C0014 and ONR N000140510076 We gratefully acknowledge the skilled technical assistance of MSSRS Andrew Barth Chris Eisenhardt Mike Fletcher Dean Marky and Eric Stimson as well as the administrative support by Ms Nancy Niedermayer
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