The effects of inspiratory muscle training with linear workload devices on the sports performance and cardiopulmonary function of athletes: A systematic review and meta-analysis

Inspiratory muscle training (IMT) is considered an ergogenic resource to improve sports performance. The aim of this systematic review is to evaluate the effects of IMT with linear workload devices (IMT-linear) on the sports performance and cardiopulmonary function of athletes. A search was conducted on several databases until July 2018. Eligible studies were independently reviewed by two reviewers. Methodological quality and quality of evidence were assessed with PEDro' score and GRADE, respectively. Statistical analysis was performed using the Review Manager 5.3 software. Twenty-five studies were selected for analysis. A total of 207 athletes were allocated to the IMT group, 143 athletes to the IMT-Sham, and 86 healthy individuals to the control group. The quality of studies was high (6 [3-8] points). IMT-linear improved maximal inspiratory pressure (MD −29.42 cmH2O [−35.65, −23.20]; p < 0.001), independent of sports modality. There was no influence of IMT on the maximal expiratory pressure and pulmonary function markers. It was observed that IMT-linear improves the sports performance (SMD 0.64 [0.35, 0.92]; p < 0.0001) with moderate effect size. The results suggest that IMT-linear represents an effective tool to improve the inspiratory muscle strength of athletes, as well as sports performance. However, IMT-linear did not shown effect on cardiopulmonary function.