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Journal of Obesity
Volume 2012, Article ID 918202, 6 pages
Clinical Study

Four Weeks of Inspiratory Muscle Training Improves Self-Paced Walking Performance in Overweight and Obese Adults: A Randomised Controlled Trial

1Institute of Sport and Exercise Science, James Cook University, Cairns, Sydney, QLD 4870, Australia
2School of Medicine and Dentistry, James Cook University, Cairns, Sydney, QLD 4870, Australia
3Baker IDI, Research and Medical Education, Central Australia, Alice Springs, NT 0871, Australia
4Department of Psychology, James Cook University, Cairns, QLD 4870, Australia

Received 20 February 2012; Revised 26 April 2012; Accepted 10 May 2012

Academic Editor: Jack A. Yanovski

Copyright © 2012 A. M. Edwards et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Objective. To examine whether a programme of inspiratory muscle training (IMT) improves accumulative distance of self-paced walking in overweight and obese adults. Methods. A total of 15 overweight and obese adults were randomized into experimental (EXP: 𝑛 = 8 ) and placebo (PLA: 𝑛 = 7 ) groups. Lung function, inspiratory muscle performance, 6-minute walking test, and predicted ̇ V O2 max were assessed prior to and following the 4-week IMT intervention. Both groups performed 30 inspiratory breaths, twice daily using a proprietary inspiratory resistance device set to 55% of baseline maximal effort (EXP), or performing the same inspiratory training procedure at the minimum resistive setting (PLA). Results. Lung function was unchanged in both groups after-training; however inspiratory muscle strength was significantly improved in EXP ( 1 9 ± 2 5 . 2  cm H2O gain; 𝑃 < 0 . 0 1 ) but did not significantly change in PLA. Additionally, the posttraining distance covered in the 6-minute walking test was significantly extended for EXP ( 6 2 . 5 ± 3 7 . 7  m gain; 𝑃 < 0 . 0 1 ), but not for PLA. A positive association was observed between the change (%) of performance gain in the 6-minute walking test and body mass index ( 𝑟 = 0 . 7 3 6 ; 𝑃 < 0 . 0 5 ) for EXP. Conclusion. The present study suggests that IMT provides a practical, minimally intrusive intervention to significantly augment both inspiratory muscle performance and walking distance covered by overweight and obese adults in a clinically relevant 6-minute walk test. This indicates that IMT may provide a useful priming (preparatory) strategy prior to entry in a physical training programme for overweight and obese adults.