Inspiratory Muscle Training At Sea Level Improves The Strength Of Inspiratory Muscles During Load Carriage In Cold-Hypoxia

Inspiratory muscle training (IMT) and functional IMT (IMTF: exercise-specific IMT activities) has been unsuccessful in reducing respiratory muscle fatigue following load carriage. IMT(F)did not include load carriage specific exercises. Fifteen participants split into two groups (training and control) walked 6 km loaded (18.2 kg) at speeds representing similar to 50%V?O(2max)in cold-hypoxia. The walk was completed at baseline; post 4 weeks IMT and 4 weeks IMTF(five exercises engaging core muscles, three involved load). The training group completed IMT and IMT(F)at a higher maximal inspiratory pressure (P-imax) than controls. Improvements in P(imax)were greater in the training group post-IMT (20.4%,p = .025) and post-IMTF(29.1%,p = .050) compared to controls. Respiratory muscle fatigue was unchanged (p = .643). No other physiological or subjective measures were improved by IMT or IMTF. Both IMT and IMT(F)increased the strength of respiratory muscles pre-and-post a 6 km loaded walk in cold-hypoxia. Practitioner Summary:To explore the interaction between inspiratory muscle training (IMT), load carriage and environment, this study investigated 4 weeks IMT and 4 weeks functional IMT on respiratory muscle strength and fatigue. Functional IMT improved inspiratory muscle strength pre-and-post a loaded walk in cold-hypoxia but had no more effect than IMT alone.