Inspiratory muscle fatigue following raced-paced swimming is not restricted to the front crawl stroke

The occurrence of inspiratory muscle fatigue (IMF) has been documented following front crawl (FC) swimming of various distances. Whether IMF occurs following other competitive swimming strokes is not known. The aim of the current study was to assess the impact of all four competitive swimming strokes on the occurrence of IMF following race-paced swimming and to determine whether the magnitude of IMF was related to the breathing pattern adopted and hence breathing frequency (fb). Eleven nationally ranked youth swimmers completed four 200-m swims (one in each competitive stroke) on separate occasions. The order of the swims, which consisted of FC, backstroke (BK), breaststroke (BR) and butterfly (FLY), was randomised. Maximal inspiratory mouth pressure (MIP) was assessed before (following a swimming and inspiratory muscle warm-up) and after each swim with fb calculated post swim from recorded data. IMF was evident following each 200-m swim (P < 0.05) but did not differ between the four strokes (range of 18-21%). No relationship (P > 0.05) was observed between fb and the change in MIP (FC: r = -.456; BK: r = .218; BR: r = .218; FLY: r = .312). These results demonstrate that IMF occurs in response to 200-m race-paced swimming in all strokes and that the magnitude of IMF is similar between strokes when breathing is ad libitum occurring no less than one breath (inhalation) every third stroke.