Biomechanics and Medicine in Swimming XI

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clAssIcAl AltItude trAInInG Classically, AT has consisted of living and training at natural (terrestrial) altitude, i.e. “living high-training high” (LH-TH). The prevailing paradigm which supports this practice is that LH-TH (about 2,000-3,000 m) is linked to an accelerated production of erythrocytes, which leads to an increase in VO2max, ultimately improving endurance performance. Surprisingly though, there are no reports in the available scientific literature of controlled studies with swimmers. Even if designs without a sea level control group are very questionable and are considered not suitable for training research, it is of note that three uncontrolled studies have tested LH-TH in swimmers. Two of them failed to prove positive effects neither on 100- and 500 yd swimming performance nor on VO- 2max (Faulkner et al., 1967; Roels et al., 2006). In fact, the latter showed a small improvement when subjects lived and trained during 13 days at 1200 m but not at 1850 m. The third study with junior swimmers is rather puzzling, since it showed an improvement on maximal speed and 4 mmol/L lactate speed in an incremental 5x100 or 5x400-m test, but not on VO 2max , despite an increase of total haemoglobin mass. A more recent approach, first developed by Levine and Stray- Gundersen and known as “living high-training low” (LH-TL), has been shown to improve sea level performance in runners of various levels. In essence, LH-TL allows robust altitude acclimatization, while simultaneously allowing athletes to ‘‘train low’’ for the purpose of replicating sea-level training intensity and oxygen flux (Levine & Stray-Gundersen, 1997; Stray-Gundersen et al., 1999). However, LH-TL, proven useful with long distance runners and orienteerers (Wehrlin et al., 2006) in events lasting 8-20 minutes, has never been tested in swimming, in which most events are below 5 min. Hence, based on available scientific literature, training at natural altitude has failed so far to prove useful for the enhancement of sea level performance in swimmers (Wilber, 2004; Truijens & Rodríguez, 2010). This fact is particularly remarkable bearing in mind that swimming coaches from many countries include AT in their planning and swimmers are among the most frequent users of high altitude training facilities. InterMIttent hYPoXIc trAInInG (Iht) Since most events in swimming require large activation of the anaerobic metabolism (Rodríguez & Mader, 2010), the enhancing effects of IHT on anaerobic metabolism or buffer capacity have lead swimming scientists to test the hypothesis that this method could improve swimming performance more than equivalent training at sea level. Two studies have been conducted with swimmers (table 1). In a first study (Truijens et al., 2003), sixteen well-trained collegiate and master swimmers were matched for gender, performance level and training history and assigned to either IHT or control groups in a randomized, double blind, placebo controlled design. All subjects completed a five week training program, consisting of three high intensity training sessions weekly in a swimming flume breathing hypoxic (≈2,500 m) or normoxic air, and supplemental low to moderate intensity sessions in a pool. Although both groups improved performance in 100- and 400-m time trials and VO 2max , no differences between groups could be demonstrated. Moreover, neither swimming economy nor anaerobic capacity improved with this training. In a second matched-paired, controlled study using a similar training regimen, Ogita and Tabata (2003) found a 10% increase in anaerobic capacity as measured by the maximal accumulated oxygen deficit (MAOD) after two weeks of hypoxic training in nine competitive male swimmers. However, both groups equally improved VO 2max and swimming performance in 100 and 200-m time trials, thus it was not possible to establish an additional benefit. InterMIttent hYPoXIA eXPosure (Ihe) Another strategy is IHE at rest or during sleep in hypobaric or normobaric environments (nitrogen houses, hypoxic tents/rooms) or using hypoxic breathing apparatuses combined with sea-level training. This chaPter1.invitedLectures should theoretically induce physiological adaptations without hampering training workload, thus allowing a comparison with LH-TL. Two IHE studies have been conducted with swimmers using hypobaric chambers (table 1). In a first study (Rodríguez et al., 2003), sixteen elite and sub-elite swimmers were assigned to one of two groups in a matched-paired, randomized design, and half of them combined sealevel training with IHE over 2 weeks (3 h/d) at a simulated altitude of 4,000-5,500 m and were compared to the control group. Although all swimmers followed identical training plans, the IHE group significantly improved swimming performance in a 200-m time trial (-1.3 s, 0.9%), associated with an increase in peak VO 2 both at 200-m (+9.3%) and 400-m (+5.4%) time trials. In a second, match-paired, randomized, double blind, placebo controlled study (Rodríguez et al., 2007), 4 weeks of 4,000-5,500 m IHE was administered to 13 swimmers and 10 runners distributed in two groups (IHE and controls). Swimmers performed duplicated 100 and 400 m time trials, and VO 2max tests in a swimming flume within three weeks before, and during the first and third week after the intervention. When swimmers were considered separately, the IHE group, but not controls, showed a significant increase in VO 2 at the ventilatory threshold (VT, +8.9) and in maximal minute ventilation (+10.6%) immediately after the intervention, as well as a significant increase in VO 2max relative to body mass (+7.5%) and VO 2 at VT (+12.1%) two weeks after, following a pre-competition taper. Intriguingly, these changes could not be attributed to increased red blood cell or haemoglobin mass (Gore et al., 2006), sub-maximal swimming economy (Truijens et al., 2008), nor to hypoxic and hypercapnic ventilatory control changes (Townsend et al., 2004). The hypothesis was raised that these changes could have been the combined effect of IHE and tapering, thus suggesting that this approach might be useful immediately before competition. In another controlled study using normobaric hypoxia, a group of swimmers spent 13 days living and training at 1200 m, while another group (IHE) was exposed to 16 h per day to simulated altitude at 2,500 (5 days) and 3,000 m (8 more days) in hypoxic rooms. Despite an increase in total haemoglobin in the IHE group (+8.5%), no improvement was observed in VO 2max or maximal speed at 4x200-m and 2,000-m maximal tests (Robach et al., 2006). Interestingly, swimmers in the control group (LH-TH at 1,200 m) did improve performance in both tests immediately after, but not 15 days after the intervention, again without any significant change in haemoglobin mass. In terms of haematological response, it is of note that a recent analysis of 15 LH-TL studies conducted at real and simulated altitude has indicated that moderate altitude/hypoxic exposure of more than 12 h per day is likely to increase total haemoglobin mass by about 1% per 100 hours of exposure (Gore et al., 2008). This would imply a minimal duration of 21 days to attain about a 5% increase in haemoglobin. Hence, despite the large amount of research performed in the last decade and some promising results, swimming performance enhancement by means of IHE is still controversial, both in terms of performance benefits and mechanisms involved, which do not seem to be related to haematological acclimatization effects. conclusIons Based on available scientific literature, there is no evidence that training at natural altitude enhances swimming performance more than training at sea level. Based on research conducted in other sports, AT would require at least 3 to 4 weeks at 2,100 to 2,500 m of altitude to elicit a robust acclimatization response (primarily red cell mass increase) in the majority of athletes. The optimal approach is likely to be LH-TL, in which one “lives high” (i.e. 2,100-2,500 m) to get the benefits of altitude acclimatization and “trains low” (1,250 m or less) to avoid the detrimental effects of hypoxic exercise. In fact, training at hypoxia (as in LH- TH or IHT) does not appear to provide any physiologic advantage over normoxic exercise and might even impair performance. Whether the 31
BiomechanicsandmedicineinswimmingXi performance benefits would be similar for swimmers compared to other endurance trained athletes is not known and requires further research. Swimming performance enhancement by means of IHE is still controversial. However, it is likely that at least 12 h/day at 2,100–3,000 m for 3 to 4 weeks may suffice to achieve a significant increase of red cell mass. Shorter exposure to more severe hypoxia (e.g. 4,000 to 5,500 m, 3 h/day for 2 to 4 weeks) combined with sea-level training may enhance VO 2max , ventilatory threshold and middle-distance swimming performance after pre-competition tapering, although the mechanisms are unclear. In any case, there is substantial individual variability in the outcome of every AT strategy. Since none of these approaches has conclusively proven to enhance swimming performance, more research is warranted to clarify their effects and mechanisms. the AltItude ProJect To clarify these effects and mechanisms in swimmers, a group of researchers from universities and sports organizations of different nations have developed a major collaborative international swimming study called The Altitude Project starting in October 2010 (Rodríguez & Levine, 2010). The project is open to sports and scientific organizations from all countries willing to contribute with recruiting and funding athletes, coaches and scientists. Information is available from: thealtitudeproject@gmail.com. reFerences Bonetti, D. L. & Hopkins, W. G. (2009). Sea-level exercise performance following adaptation to hypoxia: a meta-analysis. Sports Med, 39(2), 107-27. Chapman, R. F., Stray-Gundersen, J. & Levine, B. D. (1998). Individual variation in response to altitude training. J Appl Physiol, 85(4), 1448- 56. Faulkner, J. A., Daniels, J. T. & Balke, B. (1967). Effects of training at moderate altitude on physical performance capacity. J Appl Physiol, 23(1), 85-9. Friedmann, B., Frese, F., Menold, E. & Bartsch, P. (2005). Individual variation in the reduction of heart rate and performance at lactate thresholds in acute normobaric hypoxia. Int J Sports Med, 26(7), 531- 6. Gore, C. J., Rodriguez, F. A., Truijens, M. J., Townsend, N. E., Stray- Gundersen, J. & Levine, B. D. (2006). Increased serum erythropoietin but not red cell production after 4 wk of intermittent hypobaric hypoxia (4,000-5,500 m). J Appl Physiol, 101(5), 1386-93. Gore C. J., Clark, S. A. & Saunders, P. U. (2008). Erythropoietic and non-erythropoietic aspects of athlete performance after hypoxic exposure. Proceedings of the I International Symposium of Altitude Training (Granada): 4-7. Levine, B. D. & Stray-Gundersen, J. (1992). A practical approach to altitude training: where to live and train for optimal performance enhancement. Int J Sports Med, 13 Suppl 1, S209-12. Levine, B. D. & Stray-Gundersen, J. (1997). “Living high-training low”: effect of moderate-altitude acclimatization with low-altitude training on performance. J Appl Physiol, 83(1), 102-12. Pyne, D., Trewin, C. & Hopkins, W. (2004). Progression and variability of competitive performance of Olympic swimmers. J Sports Sci, 22(7), 613-20. Robach P., Schmitt L., Brugniaux J. V., Nicolet G., Roels B., Millet G., Hellard P., Duvallet A., Fouillot J-P., Moutereau S., Lasne F., Pialoux V., Olsen N. V. & Richalet J-P. (2006). Living high-training low: effect on erythropoiesis and aerobic performance in highly-trained swimmers. Eur J Appl Physiol, 96(4), 423-33. Roberts, D. & Smith, D. J. (1992). Training at moderate altitude: iron status of elite male swimmers. J Lab Clin Med, 120(3), 387-91. Rodríguez, F. A., Murio, J. & Ventura, J. L. (2003). Effects of intermittent hypobaric hypoxia and altitude training on physiological and 32 performance parameters in swimmers. Med Sci Sports Exerc, 35 (5), S115. Rodríguez, F. A., Truijens, M. J., Townsend, N. E., Stray-Gundersen, J., Gore, C. J. & Levine, B. D. (2007). Performance of runners and swimmers after four weeks of intermittent hypobaric hypoxic exposure plus sea level training. J Appl Physiol, 103(5), 1523-35. Rodríguez, F. A. & Mader, A. (2010, in press). Energy systems in swimming. In: Seifert, L., Chollet, D. & Mujika, I., Swimming: Science and Performance. Hauppauge, New York: Nova Science Publishers. Rodríguez, F. A. & Levine, B. D. (2010). The Altitude Project: an international collaborative research project on altitude training in elite swimmers. In, Abstracts Book, XI International Symposium for Biomechanics & Medicine in Swimming, Oslo. Roels, B., Hellard, P., Schmitt, L., Robach, P., Richalet, J. P. & Millet, G.P. (2006). Is it more effective for highly trained swimmers to live and train at 1200m than at 1850m in terms of performance and haematological benefits? Br J Sports Med, 40(2), e4. Stray-Gundersen J., Chapman R. F., Levine B. D. (2001). “Living hightraining low” altitude training improves sea level performance in male and female elite runners. J Appl Physiol, 91(3), 1113-20. Townsend N. E., Gore C. J., Stray-Gundersen J., Rodríguez F. A., Truijens M. J. & Levine B. D. (2004). Ventilatory acclimatization to intermittent hypoxia in well-trained runners and swimmers. J Appl Physiol, 36(5), S337. Truijens, M. J., Rodriguez, F. A., Townsend, N. E., Stray-Gundersen, J., Gore, C. J. & Levine, B. D. (2008). The effect of intermittent hypobaric hypoxic exposure and sea level training on submaximal economy in well-trained swimmers and runners. J Appl Physiol, 104(2), 328-37. Truijens, M. J., Toussaint, H. M., Dow, J. & Levine, B. D. (2003). Effect of high-intensity hypoxic training on sea-level swimming performances. J Appl Physiol, 94(2), 733-43. Truijens, M. J. & Rodríguez, F. A. (2010, in press). Altitude and hypoxic training in swimming. In: Seifert, L., Chollet, D., Mujika, I., Swimming: Science and Performance. Hauppauge, New York: Nova Science Publishers. Wehrlin, J. P., Zuest, P., Hallen, J. & Marti, B. (2006). Live high-train low for 24 days increases haemoglobin mass and red cell volume in elite endurance athletes. J Appl Physiol, 100(6), 1938-1945. Wilber, R. L. (2004). Altitude training and athletic performance. Champaign, Illinois: Human Kinetics.
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Pahlen Norge AS Pahlen Norge AS Cha
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