Inspiratory muscle warm-up does not improve cycling time trial performance

Combining an inspiratory muscle warm-up (IMW) with a sport specific warm-up improved intermittent running (Tong and Fu. Eur J Appl Physiol 2006; 97:673-680) and 6 min rowing time trial (Volianitis et al. Med Sci Sports Exerc 2001; 33:1189-1193) performances more than a sport specific warm-up alone. This study tested the hypothesis that an IMW would also improve cycling time trial performance. Ten competitive cyclists (VO2max 64.7 ± 8.9 mL/kg/min) performed three 10 km cycling time trials preceded by either no warm-up (CONT), a cycling specific warm-up (CYC) comprising three consecutive 5 min bouts at powers corresponding to 70, 80, and 90% of the aerobic gas exchange threshold, or a cycling specific warm-up preceded by an IMW (CYC+) comprising two sets of 30 inspiratory efforts against a pressure-threshold load of 40% maximal inspiratory pressure (MIP). During CYC and CYC+ the cycling warm-up was followed by a 2 min rest period before the start of the time trial. Performances during CYC (14.75 ± 0.79 min) and CYC+ (14.70 ± 0.75 min) were not different, although both were faster than CONT (14.99 ± 0.90 min) (P < 0.05). At 2.5 km intervals heart rate, rating of perceived exertion for leg and breathing discomfort, blood lactate concentration and pH, were not different between CYC and CYC+. Baseline MIP during CONT and CYC were 151 ± 31 and 156 ± 39 cmH2O, respectively, and these were unchanged following the time trial. IMW increased MIP from 152 ± 27 to 164 ± 27 cmH2O and no further change was observed following the time trial. In conclusion, improvements in 10 km cycling time trial performance following a specific cycling warm-up were not magnified by the addition of a specific inspiratory muscle warm-up