Take Home Points on the Inspiratory Muscle Fatigue Impairs Latissimus Dorsi Strength
Inspiratory muscle fatigue impairs latissimus dorsi activation, likely reducing swimming motor control and propulsion.
Breathing is a frequent topic of discussion at Swimming Science. Before we get started, first brush up on:
- Inspiratory Muscle Fatigue
- Brief Swimming Review Volume 1 Edition 1
Lomax (2003) first demonstrated that a 200-m race results in inspiratory muscle fatigue. He and his team of researchers then noted inspiratory muscle fatigue before a 200-m race impaired performance (Lomax 2010). Inspiratory muscle fatigue also occurs for other competitive sports (Lomax 2012). However, the specifics of inspiratory muscle fatigue and performance are not well understood.
Lomax (2014) had eight collegiate swimmers (M=6, F=2; ~22.0 years; mean 200 m freestyle 139 seconds) were recruited to perform two maximal 20 s arms only front crawl sprints in a swimming flume. Both sprints were performed on the same day and inspiratory muscle fatigue was induced 30 minutes after the first sprint. They measured maximal inspiratory and expiratory mouth pressures pre and post each sprint. The median frequency (MDF) of the electromyographic signal burst was recorded from the latissimus dorsi and pectoralis major during the 20 s sprint, along with stroke rate and breathing frequency.
After inspiratory muscle fatigue, stroke rate increased from 56 to 59 cycles/min. Latissimus dorsi MDF decreased from 67 to 61 Hz. No change was observed in the MDF of the latissimus dorsi during the control sprint. The MDF of the pectoralis major shifted to lower frequencies during both sprints but was unaffected by inspiratory muscle fatigue.
It seems inspiratory muscle fatigue only negatively influences the latissimus dorsi muscles in arms only sprint swimming. This likely decreases propulsion in freestyle and may be the main cause for impaired performance. Another interesting finding is that the pectoralis major fatigues during a 20-second sprint. Now, keep in mind breathing more frequently reduces inspiratory muscle fatigue…(Jakovljevic 2009).
- Lomax M, Tasker L, Bostanci O. Inspiratory muscle fatigue affects latissimus dorsi but not pectoralis major activity during arms only front crawl sprinting. J Strength Cond Res. 2014 Jan 7. [Epub ahead of print]
- Lomax ME, McConnell AK. Inspiratory muscle fatigue in swimmers after a single 200 m swim. J Sports Sci. 2003 Aug;21(8):659-64.
- Lomax M, Iggleden C, Tourell A, Castle S, Honey J. Inspiratory muscle fatigue after race-paced swimming is not restricted to the front crawl stroke. J Strength Cond Res. 2012 Oct;26(10):2729-33.
- Lomax M, Castle S. Inspiratory muscle fatigue significantly affects breathing frequency, stroke rate, and stroke length during 200-m front-crawl swimming. J Strength Cond Res. 2011 Oct;25(10):2691-5. doi: 10.1519/JSC.0b013e318207ead8.
- Jakovljevic DG, McConnell AK. Influence of different breathing frequencies on the severity of inspiratory muscle fatigue induced by high-intensity front crawl swimming. J Strength Cond Res. 2009 Jul;23(4):1169-74. doi: 10.1519/JSC.0b013e318199d707.