Updated: Mar 8, 2019
In any event longer than 10 seconds, breathing is essential to continue racing or training. As intensity increases, we naturally breathe harder which improves efficiency and economy of the muscles that are used to expand and contract our lungs. These respiratory muscles are also improving but what if we could train those breathing muscles independently of our normal training sessions? Can breathing exercises improve breathing muscles and, more importantly, overall performance? Is so, how does it work, and what is needed to exercise our breathing muscles?
Breathing Anatomy 101
The primary respiratory muscles are the external intercostals, the internal intercostals, and the diaphragm. The external intercostals, seen below left, are attached to the ribcage and assist with inhalation by raising the rib cage up and out. The internal intercostal muscles, seen below right, also attached to the ribcage, contract to push the ribcage back and depress the chest cavity inward to help exhale air. The diaphragm, as seen above, contracts (moves down toward the stomach) to further expand the chest from below. When exhaling, the diaphragm relaxes and lets the lungs reduce in size and push air out. The correct timing and sequence of these muscles allow us to breathe during exercise and competition (exhalations at rest are more passive). The abdominals and the sternocleidomastoids also help with breathing but don’t need to be the focus here.
Is There Proof Respiratory Muscle Training Works?
Four systematic reviews on Respiratory Muscle Training (RMT) (1, 2, 3, 4) have been published, two as recently as 2018. RMT in the form of forceful inhalations is termed “inspiratory muscle training” or IMT. All reviews conclude IMT does improve performance for endurance and sprint events in aquatic and land-based sports. IMT has been shown to improve exercise capacity and performance in time-trials in multiple sports. IMT seems to be the way to practice RMT.
"Respiratory muscle training can increase athletic performance and respiratory muscle strength and endurance"(4).
Forceful breaths out are termed “expiratory muscle training” or EMT. EMT also seems to improve performance, however, EMT is not advised as forceful exhalations can lead to lightheadedness due to the drop in thoracic pressure.
Here’s a sample of how much overall performance is improved when an athlete adopts RMT (each bullet represents a different study):
1.7%, 1.5%, and 1% improvement in 100, 200, 400 free time trials, respectively. Method of IMT training: 30 breaths a day, 2 times per day, 7 days a week for 6 weeks (2010).
3% and 4% improvement in 50 and 200m time trials, respectively. Method of IMT training: 30min a day, 5 days a week for 8 weeks (2013).
2% improvement in 50 and 100m swims. Method of IMT training: 30 breaths a day, 2 times per day, 7 days a week for 6 weeks (2013).
3% and 7% improvement in 100 and 200m swim trials, respectively. Method of IMT training: 30 breaths a day, 2 times per day, 7 days a week for 6 weeks.
10% improvement in power output; 6% improvement in speed in both cycling and running. Method of IMT training: 20min a day, 2 times per day, 7 days a week for 5 weeks.
16.3% improvement in running tests to exhaustion (7); Method of IMT training: 30 breaths a day, 2 times per day, 6 days a week for 6 weeks.
"Sports performance tests showed highly significant improvements in response to respiratory muscle training compared to control groups"(4).
*Researchers discovered an interesting aspect of IMT on swim training. Those swimmers who’s training volume is already high – 40 to 60km per week – did not benefit from IMT. It was theorized that the high amount of hydrostatic pressure on the lungs due to the amount of time spent in the water resulted in a ‘natural’ way to improve respiratory muscle capacity and functioning. It was also theorized that swimmers who are swimming 40km or more per week can benefit from IMT, but they need to perform more than 30 breaths, twice a day to experience the benefits of IMT. It is unknown how much more IMT training needs to be done. I would surmise more than 30 breaths (40 breaths, 50 breaths per session?) performed 2-3 times a day. There are other reasons for swimmers to use IMT who swim high weekly volumes (more below). Anecdotally, this author has received feedback from land-based sport practitioners on how swimming has improved their on-land conditioning. The improved conditioning could be from additional training or from the ‘natural’ IMT that swimming provides.
Part 2 of this series will cover the mechanisms on how respiratory muscle training works and using RMT during warm-up and before racing to improve performance...
Shei, R. J. (2018). Recent advancements in our understanding of the ergogenic effect of respiratory muscle training in healthy humans: A systematic review. The Journal of Strength & Conditioning Research, 32(9), 2665-2676.
Karsten, M., Ribeiro, G. S., Esquivel, M. S., & Matte, D. L. (2018). 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. Physical Therapy in Sport.
Gualdi, L. P., Sales, A. T., Fregonezi, G., Ramsook, A., Guenette, J., Lima, I., & Reid, D. (2015). Respiratory muscle endurance after resiratory muscle training in athletes and non-athletes: A systematic review and meta-analysis.
HajGhanbari, B., Yamabayashi, C., Buna, T. R., Coelho, J. D., Freedman, K. D., Morton, T. A., ... & Reid, W. D. (2013). Effects of respiratory muscle training on performance in athletes: a systematic review with meta-analyses. The Journal of Strength & Conditioning Research, 27(6), 1643-1663.
Menzes KKP, Nascimento LR, Avelino PR, Polese JC, Salmela LFT (2018). A Review on Respiratory Muscle Training Devices . J Pulm Respir Med 8: 451. doi: 10.4172/2161-105X.1000451
Leddy, J. J., Limprasertkul, A., Patel, S., Modlich, F., Buyea, C., Pendergast, D. R., & Lundgren, C. E. (2007). Isocapnic hyperpnea training improves performance in competitive male runners. European journal of applied physiology, 99(6), 665-676.
Wilson, E. E., McKeever, T. M., Lobb, C., Sherriff, T., Gupta, L., Hearson, G., ... & Shaw, D. E. (2014). Respiratory muscle specific warm-up and elite swimming performance. Br J Sports Med, 48(9), 789-791.
Tong, T. K., Fu, F. H., Chung, P. K., Eston, R., Lu, K., Quach, B., ... & So, R. (2008). The effect of inspiratory muscle training on high-intensity, intermittent running performance to exhaustion. Applied physiology, nutrition, and metabolism, 33(4), 671-681.