Alterations in maximal inspiratory mouth pressure during a 400-m maximum effort front-crawl swimming trial

Aim. The aim of this study was to examine the changes of maximal inspiratory month pressure (PImax) during a 400-m front crawl swimming trial. Methods. Eleven well-trained competitive swimmers (age: 17.6.+/-0.8 years, mean+/-SE) performed a 400-m front-crawl trial with maximum effort (296.2+/-4.76 s). Then, on different days they swam a 300-m, 200-m and 100-m trials at a velocity corresponding to the 400-m trial. Measurements of PImax from residual volume at upright body position before and immediately after each trial were conducted using a portable mouth pressure meter. Results. Maximal inspiratory mouth pressure did not change significantly after the 100-m and 200-m trial compared to baseline (131.8+/-9.7 and 123.7+/-10.3 vs. 140.9+/-8.9 cmH(2)O P>0.05). However, PImax was significantly lower after the 300-m (118.8+/-7 cmH(2)O, P=0.02) and 400-m trials (118.1+/-9.9 cmH(2)O, P=0.01). Conclusions. These results indicate that during a maximum effort of 400-m front crawl, the reduction of inspiratory muscle strength occurs after 300-m. This should be considered for competitive swimming training by implementing swim race distance-specific respiratory muscle training.