Inspiratory muscle fatigue in swimmers after a single 200 m swim

Abstract

Inspiratory muscle fatigue may occur in as little as 6 min during high-intensity spontaneously breathing exercise. The aims of this study were to determine whether inspiratory muscle fatigue occurs during swimming exercise and whether inspiratory muscle strength differs between the supine and standing body positions. Seven competitive swimmers were recruited to perform a single 200 m front-crawl swim, corresponding to 90-95% of race pace. Inspiratory muscle strength was measured at residual volume using a hand-held mouth pressure meter that measured maximal inspiratory pressure in the upright and supine positions. At baseline, maximal inspiratory pressure in the supine position was significantly lower than maximal inspiratory pressure in the upright position (112 +/- 20.4 and 133 +/- 16.7 cmH2O, respectively; P < or = 0.01). Post-exercise maximal inspiratory pressure in the supine position (80 +/- 15.7 cmH2O) was significantly lower than baseline maximal inspiratory pressure in the supine position (P < or = 0.01). The results indicate that a single 200 m front-crawl swim corresponding to 90-95% of race pace was sufficient to induce inspiratory muscle fatigue in less than 2.7 min. Furthermore, although diaphragm muscle length is optimized when supine, our results indicate that the force output of the diaphragm and inspiratory accessory muscles is greater when upright than when supine.

Runners maintain locomotor–respiratory coupling following isocapnic voluntary hyperpnea to task failure

“…As such, applying the findings from this study to exercise-induced respiratory muscle fatigue necessitates caution. Nonetheless, the declines in maximal volitional mouth pressures in our highly motivated subjects following IVH were similar to, though slightly less than, those seen following exerciseinduced RMF (e.g., 10 and 7 % declines in MIP and MEP, respectively, in our subjects vs. 10-28 % in previous investigations) (Coast et al 1999;Cordain et al 1994;Lomax and Castle 2011;Lomax and McConnell 2003;Romer et al 2002). Moreover, the significant inverse correlations between change in MIP and ventilatory loads (i.e., total volume and time to fatigue) are in agreement with the concept that degree of muscular fatigue is related to muscular work, further implying that the volitional measure, despite its limitations (American Thoracic Society/European Respiratory 2002), was likely indicative of global respiratory fatigue.…”

Ventilation and Respiratory Mechanics

“…These measurements are noninvasive and have potential for the assessment of exercise-induced respiratory muscle fatigue, as demonstrated by the transient fall in pressures after high-intensity sustained exercise (82,100,101,187,317,452,547) and longer duration endurance exercise (93,107,223,316,455). The major limitation of maximal volitional pressures as measures of fatigue is that they are highly dependent on the subject's effort and therefore susceptible to changes in motivation or other central factors.…”

Pulmonary adaptations to swim and inspiratory muscle training

“…Wells and coworkers (Wells et al 2005) have shown that 12 weeks of CRMT can increase critical swimming speed in female, but not male, adolescent competitive swimmers, whereas Wylegala et al (Wylegala et al 2007) recently demonstrated that 4 weeks of respiratory muscle training improved swimming endurance in scuba divers. Interestingly, research on competitive Masters Swimmers has shown that a single 200 m freestyle swim corresponding to 90-95% of race pace was sufficient to induce inspiratory muscle fatigue (IMF) (Lomax and McConnell 2003). Whether this IMF developed during swimming (Lomax and shown to occur after the swim phase of a triathlon (Hill et al 1991).…”