ORIGINAL ARTICLE  EXERCISE PHYSIOLOGY AND BIOMECHANICS 

The Journal of Sports Medicine and Physical Fitness 2019 December;59(12):1975-84

DOI: 10.23736/S0022-4707.19.09578-1

Copyright © 2019 EDIZIONI MINERVA MEDICA

language: English

Improvements in soccer-specific fitness and exercise tolerance following 8 weeks of inspiratory muscle training in adolescent males

Abdolrahman NAJAFI ¹, Khosro EBRAHIM ¹, Sajad AHMADIZAD ¹, Gholam R. JAHANI GHAEH GHASHLAGH ², Mohsen JAVIDI ¹, Daniel HACKETT ³ ✉

¹ Department of Exercise Physiology, Faculty of Physical Education and Sport Sciences, Shahid Beheshti University, Tehran, Iran; ² Department of Exercise Physiology, Faculty of Humanities, Abhar Branch Islamic Azad University, Zanjan, Iran; ³ Exercise, Health and Performance Faculty Research Group, Faculty of Health Sciences, The University of Sydney, Lidcombe, Australia

BACKGROUND: Inspiratory muscle training has been shown to improve exercise performance, however there is limited evidence for its effectiveness in soccer players. This study investigates the effect of inspiratory muscle training on soccer-specific fitness and exercise tolerance in adolescent male players.
METHODS: Thirty highly trained soccer players (16-19 y) were randomly assigned into one of three groups: experimental 1 (N.=10), experimental 2 (N.=10) and sham-control (sham, N.=10). All groups performed inspiratory muscle training twice per day and five times per week for 8 weeks. Experimental 1 performed 25-35 breaths at 55% maximal inspiratory pressure, experimental 2 performed 45-55 breaths at 40% maximal inspiratory pressure, whereas sham performed 30 breaths at 15% maximal inspiratory pressure. Measures before and after the intervention involved the Yo-Yo Intermittent Recovery test level 1, running-based anaerobic test, repeated high-intensity endurance test, maximal inspiratory pressure, and spirometry.
RESULTS: Yo-Yo Intermittent Recovery test level 1: distance increased for experimental groups 1 and 2 compared to sham (P=0.012 and P=0.031, respectively), with no difference between experimental groups. Fatigue index calculated from running-based anaerobic test improved for experimental groups 1 and 2 compared to sham (P=0.014 and P=0.011, respectively), with no difference between experimental groups. Exercise tolerance (i.e. blood lactate concentration, perceived exertion and perceived breathlessness) following the repeated high-intensity endurance test decreased in experimental groups 1 and 2 compared to sham (P <0.05), with no difference between experimental groups. Maximal inspiratory pressure increased for experimental groups 1 and 2 compared to sham (P=0.000), with no difference between experimental groups. There were no changes for the spirometry measures.
CONCLUSIONS: Improvements in soccer-specific fitness and exercise tolerance can be achieved using inspiratory muscle training protocols of varying intensities and volumes.

KEY WORDS: Respiratory muscles; Exercise tolerance; Soccer; Anaerobic threshold; Athletic performance