The main reason for the use of wetsuits in swimming is to avoid hypothermia, which led to their use in open water and triathlon competitions (Parsons and Day, 1986). The use of wetsuits varies, being mandatory, optional or prohibited depending on the water temperature in both sports. On the one hand, in open water swimming the optional use is allowed when the water temperature is between 18 and 20ºC, being mandatory below 18ºC and prohibited above 20ºC, (Marculescu, FINA, 2017). However, in triathlon, there are wider temperature ranges that vary depending on both the category of the triathlete and the distance of the event (see Competition Rules, ITU, 2019).
However, the design of wetsuits has come a long way over time. Different synthetic materials are used in addition to the basic neoprene fabric which is made of small bubbles of gases (such as air, nitrogen and hydrogen) that insulate from the cold by creating a thermal layer between the swimmer’s body and the water (Naebe et al., 2013). The design should not exceed the maximum thickness measurements allowed by both the International Swimming Federation (FINA) and the International Triathlon Federation (ITU); both allow 5 mm maximum thickness. In addition, there are several types of wetsuit designs: full-body wetsuit (covering the whole body except the head, hands and feet), sleeveless long wetsuit (covering the torso and lower limbs up to the ankles) and sleeveless short wetsuit (covering only the torso and lower limbs up to the knees).
Figure 1-3. Endless Pool Elite Techno Jet Swim 7.5 HP, gas analyzer K4b2, and Snorkel Aquatrainer®.
These patterns derive from the discomfort of swimming long distances with wetsuit, particularly affecting the shoulder joint. As studied, swimmers tend to feel more comfortable than triathletes wearing sleeveless wetsuits, as the wetsuit limits their shoulder movement (Chatard et al., 1995 and Perrier and Monteil, 2001). On the other hand, swimmers who adopt a less hydrodynamic position while swimming tend to benefit more from wearing a wetsuit that covers their entire lower limbs. Therefore, although the wetsuit improves swimming performance due to the increased buoyancy provided by the material, which leads to an improvement in the hydrodynamic position and, in turn, decreases drag resistance (Zamparo et al., 2020), this improvement varies according to the swimmer’s ability, with less experienced swimmers or swimmers with poorer swimming technique gaining greater advantages (Chatard et al., 1995 and Perrier and Monteil, 2001).
In our Aquatics Lab we have analyzed how much the wetsuit improves swimming performance in a 400 m front crawl in both a swimming flume (Endless Pool Elite) and in a 25 m swimming pool and at different temperatures (26 and 18ºC). We have been able to corroborate, as previously studied, how swimmers increase their swimming speed by 0.07 m/s with wetsuit compared to conventional swimsuit, resulting in a 6% of improvement on 400 m front crawl performance (20.08 seconds) (Gay et al., 2020). In addition, swimming in cold water with wetsuit (18ºC) does not produce physiological alterations that may impair performance, so its use is recommended when the water temperature is between 18 and 20º (optional use for open water swimming) (Gay et al., 2021).
Applications for coaches
There are many variables that affect this performance improvement with the use of wetsuit, both biomechanical (e.g., stroke frequency, stroke length, stroke index, and propelling efficiency) and physiological (e.g., heart rate, maximal oxygen consumption, and blood lactate concentration) parameters. All of them vary when using wetsuit or swimsuit, so they must be taken into account in the daily training of the swimmer and triathlete, since biomechanical and physiological adaptations to the use of the wetsuit is a fundamental factor to benefit from its properties.
Full version of the studies
Gay A, López-Contreras G, Fernandes RJ, Arellano R. (2020). Is Swimmers’ Performance Influenced by Wetsuit Use? International Journal of Sports Physiology and Performance, 15(1): 46-51. https://doi.org/10.1123/ijspp.2018-0891
Gay, A., Zacca, R., Arturo, A., Morales-Ortiz, E., López-Contreras, G., Fernandes, R., & Arellano, R. (2021). Swimming with swimsuit and wetsuit at typical vs cold-water temperatures (26 vs 18ºC). International Journal of Sports Medicine, 42, 1-8. doi:10.1055/a-1481-8473.
FUNDING
These studies were supported by grants awarded by the Ministry of Science, Innovation, and Universities (Spanish Agency of Research) and the European Regional Development Fund (ERDF): DEP2014-59707-P ‘SWIM: specific water innovative measurements applied to the development of the international swimmers in short swimming events (50 and 100 m)’ and PGC2018-102116-B-I00 ‘SWIM II: Specific Water Innovative Measurements: Applied to the performance improvement’ and the Spanish Ministry of Education, Culture and Sport: FPU16/02629 grant.
REFERENCES
Parsons L, Day S. Do wet suits affect swimming speed? (1986). British Journal of Sports Medicine, 20(3):129-131.
Fédération Internationale de Natation / Marculescu C (2017). Swimwear for open water swimming events. FINA Rules Memorandum. https://www.fina.org/swimming/approved-swimwear.
International Triatlon Union. ITU Competition Rules (2019). https://www.triathlon.org/uploads/docs/itusport_competition-rules_2019.pdf.
Naebe M, Robins N, Wang XG, Collins P. (2013). Assessment of performance properties of wetsuits. Proceedings of the Institution of Mechanical Engineers Part P-Journal of Sports Engineering and Technology, 227(4):255-264.
Zamparo, P., Cortesi, M., & Gatta, G. (2020). The energy cost of swimming and its determinants. European journal of applied physiology, 120(1), 41-66.
Chatard JC, Senegas X, Selles M, Dreanot P, Geyssant A. (1995). Wet suit effect: a comparison between competitive swimmers and triathletes. Medicine & Science in Sports & Exercise, 27(4):580-586.
Perrier D, Monteil KM. (2001). Wetsuits and performance: Influence of technical abilities. Journal of Human Movement Studies, 41(3):191-207
Gay A, López-Contreras G, Fernandes RJ, Arellano R. (2020). Is Swimmers’ Performance Influenced by Wetsuit Use? International Journal of Sports Physiology and Performance, 15(1): 46-51.
Gay, A., Zacca, R., Arturo, A., Morales-Ortiz, E., López-Contreras, G., Fernandes, R., & Arellano, R. (2021). Swimming with swimsuit and wetsuit at typical vs cold-water temperatures (26 vs 18ºC). International Journal of Sports Medicine, 42, 1-8. doi:10.1055/a-1481-8473.
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