Triathlon Clothing: the benefits of wearing a wetsuit

Triathletes – why a wetsuit will improve your swimming leg

If you’re a triathlete, you’ve got to like wetsuits. They keep frigid water from paralysing your arm and leg muscles and sinking your ship before you make it to shore, and they can improve swimming speed by 3 to 7 per cent, enough to give you a 50- to 100-metre edge over a suitless competitor in a 1500-metre swim.

Scientific studies have shown that wet suits improve swimming speed more in short events (400 metres) than in longer ones (1500 metres) and help lean swimmers far more than corpulent ones. The special edge for skinny swimmers occurs because one of the main effects of a neoprene wetsuit is to improve an individual’s buoyancy. Plump people already have decent buoyancy because they have their own built-in wet suits – blankets of blubber encasing their frames. Skinny people float badly because they have little buoyant blubber, and their heavy body parts (bones and muscles) tend to sink like stones. By improving buoyancy, wet suits let swimmers expend less energy to avoid sinking; they can stay in a horizontal position near the top of the water column without much trouble. That means that more effort can be expended on direct, forward propulsion…

Suits help swimmers in another way: the smooth surface of the suit cuts down on ‘drag’ – the friction between a swimmer’s body and the water. Scientists estimate that wetsuits reduce this performance-lowering drag by about 14 per cent.

However, it hasn’t been clear whether wetsuits actually help all types of swimmers. For example, topnotch swimmers might not need wet suits, since they have already streamlined themselves by shaving off body hair and have optimised their movements by upgrading the skill of their strokes and kicks. It’s possible that excellent triathletes might also benefit little from suits – for similar reasons. Perhaps only novice or unskilled swimmers get much of a boost from the suits…

Swimmers vs. triathletes
To see what impact wetsuits would have on different types of athletes, scientists in France recently evaluated two groups of swimmers – international-level swimmers and international-level triathletes. The swimmers had been training about 17 hours per week for a total distance of 60 kilometres; the triathletes averaged 15 hours of training each week but only four hours of actual swimming, covering a total of 13 kilometres. Average age in each group was 21 years, but swimmers were considerably heavier (167 vs. 154 pounds). The swimmers were also considerably faster than the triathletes, with average PBs of 3:58 for 400 metres, versus 4:49 for triathletes…

Without wetsuits, swimmers swam faster than triathletes, had higher VO2maxs, lower energy costs of swimming (by 21 to 29 per cent), and less drag (4 to 8 per cent). With wetsuits, swimmers still swam faster and enjoyed better swimming economy (by 15 to 21 per cent), but actual drag was the same for both groups…

Somewhat surprisingly, wetsuits didn’t significantly improve performances among the international-calibre swimmers, who averaged about 4:13 for 400 metres with or without a suit. However, wetsuits had an extremely positive impact on triathletes’ performances, lowering 400-metre clocking from 5:05 to 4:46…

Explaining the difference
Why did the suits help the triathletes but not the swimmers? For one thing, the suits didn’t lower drag or the energy cost of swimming in swimmers but diminished drag by 10 to 22 per cent in the triathletes and lowered their actual cost of swimming by 7 to 20 per cent. This is partially because swimmers naturally had better buoyancy than the triathletes, since they were slightly fatter and could also fill their lungs to a greater extent with air. Thus, slipping into a buoyant wet suit had a smaller impact on their performances…

Another factor may have been that the greater training load of the swimmers (17 vs. 4 hours of swimming per week) made them more skilled at keeping their bodies in a horizontal body position near the top of the water column. Thus, the basic positive effect of a wet suit – getting the body up and flat in the water with no sinking legs or feet – had already been achieved through long hours of practice by the experienced swimmers…

As we’ve mentioned, wetsuits help skinny, less-skilled swimmers (the kind who tend to sink) far more than those who are extremely skilled and have a little fat under their skins. In the French study, the wet suits simply kept the skinny triathletes, who were not really top-level swimmers, from sinking. As a result, with suits they were able to divert energy away from keeping themselves buoyant and into the process of steaming straight ahead…

As a result, the triathletes swam the 400 about 6-per cent faster while wearing suits, compared to the suitless condition. Other studies support the idea that wetsuits can boost the performances of non-superstar swimmers. In one piece of research, 14 female intercollegiate (Division I) swimmers were able to cover the 400 about 5 per cent faster when wearing suits. Similarly, another study found that triathletes could swim about 7-per cent further in 30 minutes while wearing wetsuits…

The bottom line? Most of us can swim faster when we slip into a neoprene wetsuit. In fact, a suit can often knock about 5 per cent from our swim times, enough to give about a 75-metre edge in a 1500-metre swim. Thus, it makes sense to slip into a suit, even when the water is not especially cold (bearing in mind that suits are not allowed in sanctioned competitions over the Olympic distance when the water temperature is over 21 degrees Centigrade – or over 24 degrees for long-distance triathlons). The leaner we are, and the less skilled our swimming technique, the greater will be the positive effect of the suit…

Owen Anderson

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