High-Altitude Training Does Not Improve Swimming Performance

"Michael Phelps has slept in a hyperbaric chamber in preparation for these London Olympics".
 
"The secret to Floyd Landis' training is a hyperbaric chamber".
 
“Missy grew up in Colorado, so she has been training at altitude since a kid”.
 
For all those living in the pool, Floyd Landis was the 2006 Tour de France champion, until he tested positive for performance enhancing drugs and stripped of his title. These two quotes are not meant to accuse Mr. Phelps, the greatest swimmer of all time, is using performance enhancing drugs, but to bring to light the myths surrounding the topic of high-altitude training.

 
In the United States, there are two main sites for altitude training, Flagstaff AZ and the Olympic base of Colorado Springs. Altitude training has been attractive to swimming coaches since the USOC Training Center opened. However, Dr. Rushall, renowned swimming researcher, feels the use of high-altitude training is a form of 'armchair theorizing' and poorly designed research. After a literature review, his views seem justified, despite the continued support by Olympic committees.
 
In fact, for about 10 years opposing evidence dismisses the use of these forms of training. However, current uses persist like Phelps and the Australians supposedly using a tent over their training pool before the London Olympics (read about the Australian’s performance at these Olympics). 
 
Dr. Rushall discussed this topic in his Future of Swimming: “Myths and Science” piece. His research suggests:
 
"For swimming, the following conclusions have been supported.
• Intermittent hypoxia (residing in an altitude tent) does not improve swimming performance economy (Truijens, Rodriguez, Palmer, Townsend, Gore, Stray-Gundersen, & Levine, 2004) or produce any beneficial effects (Truijens, Dow, Cabayo, Palmer, Witkowski, Chase, Toussaint, & Levine, 2002; Truijens, Palmer, Witkowski, Chase, van Asseldonk, Toussaint, & Levine, 2003).
• Erythropoietin (EPO) changes due to altitude and intermittent hypoxia are not associated with total hemoglobin mass [and therefore do not have the potential to influence swimming performance] (Friedmann, Frese, Menold, Kauper, Jost, & Bartsch, 2005). Elevated EPO
augmentation is likely of little benefit to conditioned athletes (Spivak, 2001).
• Swimmers' sea level performances are not associated with total hemoglobin mass (Friedmann et al.).
• Swimmers' ventilatory responses are not improved by intermittent hypoxia although sedentary individuals do exhibit improvements (Townsend, Gore, Truijens, Rodriguez, Stray- Gundersen, & Levine, 2004).
• Altitude residence does not affect the ventricular structure of swimmers (Haykowsky, Smith, Malley, Norris, & Smith, 1998).
• Simulated altitude conditions reduce both swimming performances and physiological factors (Toussaint, Truijens, van Asseldone, & Levine, 2004).
• Altitude residents improve swimming times when they compete at sea level (D'Acquisto, Tran, Jackson, & Troup, 1996)."
 
Hypoxia was also proposed to improve VO2max, however Salgado in 2009 also found VO2max did not improve with hypoxia. Therefore, this potential benefit from high-altitude should likely be discredited.
 
Many advocates of high-altitude training support their cases with research based off of non- or low-level athletes (Bonetti 2009). They concluded that non- or low-level athletes benefit by some forms of hypoxic training. This study also found the live-high - train-low theory resulted in small benefits of elite athletes, but this training did consist of other confounding variables, which potentially provided the small performance benefits (Rushall 1993). This makes this evidence poor quality, requiring blinding and randomization.

High Altitude Training

Luckily high quality evidence is surfacing, further discrediting the live high, train low theory. Siebenmann 2012 performed a placebo-controlled, double-blinded study questioning the efficacy of this training. These researchers found:
 
"Weekly training effort was similar between groups. Hb mass, maximal oxygen uptake (VO(2)) in normoxia, and at a simulated altitude of 2,500 m and mean power output in a simulated, 26.15-km time trial remained unchanged in both groups throughout the study. Exercise economy (i.e., VO(2) measured at 200 W) did not change during the LHTL intervention and was never significantly different between groups. In conclusion, 4 wk of LHTL, using 16 h/day of normobaric hypoxia, did not improve endurance performance or any of the measured, associated physiological variables. "

This is stronger evidence, once again suggesting altitude does not improve swimming performance.

Summary
As old and new research suggests, altitude training and hypoxic tents seem irrelevant in training.
To close, I'll quote Rushall, the man making these statements for over a decade:
"For swimming, altitude training camps and experiences are expensive follies."
 
However, it is important to note, these camps have other valuable resources other than altitude. Therefore, using these facilities for underwater analysis, biomechanics, injury prevention/rehabilitation, etc. is essential and beneficial. But, be skeptical of certain philosophies and training performed by elite athletes. Research on this subject has been around for a decade, despite the continued application. 

Don’t fall into the TRAP of being an armchair theorist. Stay on top of current research (Swimming Science Research Review) and use it with your anecdotal evidence on deck, as balancing these two sources leads to performance benefits.
 

References:

1. Rowbottom, D., Maw, G., Raspotnik, L., Morley, E., & Hamilton, E. (2001). Biological variables to assist in fatigue  management are individualized in highly trained swimmers.  Medicine and Science in Sports and Exercise, 33(5), Supplement abstract 1920.
2. Rushall, B. S. (1967).  The scientific bases of circulorespiratory training. Unpublished master's thesis, Indiana  University, Bloomington, Indiana.
3. Rushall, B. S. (1993). Comments on altitude. Coaching Science Abstracts, 24, [C:\CSA\CSA\vol24\rushall2.htm]
4. Rushall, B. S., (April, 2002). On US Swimming's promotion of altitude, live-high—train-low, and nitrogen tent recovery  and training protocols. Swimming Science Journal. [http://coachsci.sdsu.edu/swim/Training/rushall3.htm]
5. Rushall, B. S. (2003). Foundational principles of physical conditioning. Spring Valley, CA: Sports Science Associates.
6. Rushall, B. S. (2003b). Biomechanics of human movement. Spring Valley, CA: Sports Science Associates.
7. Rushall, B. S. (2003c). Coaching development and the second law of thermodynamics [or belief-based versus evidencebased coaching development. Coaching Science Abstracts. [http://coachsci.sdsu.edu/csa/thermo/thermo.htm]
8. Rushall, B. S. (2006). Swimming pedagogy and a curriculum for stroke development. Spring Valley, CA: Sports Science  Associates [Electronic book].
9. Rushall, B. S. (2009a). The science, physics, and biomechanics of baseball pitching. Spring Valley, CA: Sports Science  Associates [Electronic book].
10. Rushall, B. S. (2009b). The neural and psychological bases of baseball pitching. Spring Valley, CA: Sports Science  Associates [Electronic book].
11. Rushall, B. S. (2009c). Foundational and programming principles of conditioning baseball pitchers. Spring Valley, CA:  Sports Science Associates [Electronic book].
12. Rushall, B. S. (no date a). Actual hand movement paths of champion male crawl stroke swimmers. Swimming Science  Bulletin, 33. [http://coachsci.sdsu.edu/swim/bullets/pathfs33.htm]
13. Rushall, B. S. (no date b). Actual hand movement paths of two champion back stroke swimmers. Swimming Science  Bulletin, 34. [http://coachsci.sdsu.edu/swim/bullets/pathbk34.htm]
14. Rushall, B. S., & King, H. A. (1994a). The value of physiological testing with an elite group of swimmers.  The  Australian Journal of Science and Medicine in Sport, 26(1/2), 14-21.
15. Rushall, B. S., & King, H. A. (1994b). Letter to the editor. The Australian Journal of Science and Medicine in Sport, 26, 77.
16. Rushall, B. S., & Pyke, F. S. (1991). Training for sports and fitness. Melbourne, Australia: Macmillan of Australia.
17. Rushall, B. S., Buono, M. J., Sucec, A. A., & Roberts, A. D. (1998). Elite swimmers and altitude training. Australian  Swim Coach, 14(4), 22-33.
18. Rushall, B. S., Holt, L. E., Spriging
19. Salgado, R. M., Parker, D. L., & Quintana, R. (2009). The effects of hypoxic manipulation on VO2max and sea-level  performance: A meta-analysis. ACSM 56th Annual Meeting, Seattle, Washington. Presentation number 2789.
20. Bonetti, D. L., & Hopkins, W. G. (2009). Sea-level  exercise performance following adaptation to hypoxia: A metaanalysis. Sports Medicine, 39, 107-127.
21. D'Acquisto, L. J., Tran, Z. V., Jackson, C. G. R.,  & Troup, J. P (1996). Energy release during altitude and acute  simulated sea level exposure in altitude acclimatized/trained swimmers. In J. P. Troup, A. P. Hollander, D. Strasse, S. W.  Trappe, J. M. Cappaert, & T. A. Trappe (Eds.), Biomechanics and Medicine in Swimming VII (pp. 140-145). London: E  & FN Spon.
22. Haykowsky, M.J., Smith, D.J., Malley, L., Norris, S.R., & Smith, E.R. (1998). Effects of short-term altitude training and  tapering on left ventricular morphology in elite swimmers. Canadian Journal of Cardiology, 14(5), 678-681.  
23. Townsend, N. E., Gore, C. J., Truijens, M. J., Rodriguez, F. A., Stray-Gundersen, J., & Levine, B. D. (2004). Ventilatory  acclimatization to intermittent hypoxia in well-trained runners and swimmers.  Medicine and Science in Sports and Exercise, 36(5), Supplement abstract 2315.
24. Friedmann, B., Frese, F., Menold, E., Kauper, F., Jost, J., & Bartsch, P. (2005). Individual variation in the erythropoietic  response to altitude training in elite junior swimmers.  British Journal of Sports Medicine, 39(3),  148-153.  [http://c
25. oachsci.sdsu.edu/csa/vol146/friedman.htm]
26. Spivak, J. L. (2001). Erythropoietin use and abuse: When physiology and pharmacology collide. Advances in Experimental Medicine and Biology, 502, 207-224. [http://coachsci.sdsu.edu/csa/vol116/spivak.htm]
27. Siebenmann C, Robach P, Jacobs RA, Rasmussen P, Nordsborg N, Diaz V, Christ A, Olsen NV, Maggiorini M, Lundby C. "Live high-train low" using normobaric hypoxia: a double-blinded, placebo-controlled study. J Appl Physiol. 2012 Jan;112(1):106-17. Epub 2011 Oct 27. Truijens, M. J., Rodriguez, F. A., Palmer, D., Townsend, N. E., Gore, C. J., Stray-Gundersen, J., & Levine, B. J. (2004). The effect of intermittent hypobaric hypoxic exposure on economy in runners and swimmers. Medicine and Science in Sports and Exercise, 36(5), Supplement abstract 2318
28. Truijens, M. J., Dow, J., Cabayo, J., Palmer, D., Witkowski, S., Chase, P., Toussaint, H. M., & Levine, B. D. (2002). The effect of high intensity hypoxic training on sea-level swimming performances. Medicine and Science in Sports and Exercise, 34(5), Supplement abstract 1337.
29. Truijens, M. J., Palmer, D., Witkowski, S., Chase, P., van Asseldonk, E., Toussaint, H. M., & Levine, B. D. (2003). The effect of high intensity, hypoxic training on VO2 kinetics in well trained swimmers. Medicine and Science in Sports and Exercise, 35(5), Supplement abstract 1861.