In this blog post, we’ll explore how the scientific principles behind full-body swimsuits contribute to improving swimming times.
The Summer Olympics, a global celebration held once every four years. At the most recent Olympics, there were several instances in the swimming events where the winner of a medal changed by a margin of just 0.01 seconds. As such, even the slightest improvement in time is crucial for athletes. That’s why countless athletes endure grueling training over long periods, but in fact, beyond an athlete’s effort and ability, there are engineering technologies that help improve performance.
People often think of swimsuits as simply clothing worn for swimming. They also assume that the more of the body a swimsuit covers, the more it restricts movement, which would actually slow down performance. However, contrary to this common belief, full-body swimsuits have demonstrated superior performance compared to standard swimsuits in terms of improving times. Since swimming is a sport where athletes compete in the water while wearing swimsuits, the swimsuit itself can be considered one of the key factors in improving times. In fact, scientists have focused their research on swimsuits for many years, resulting in the development of a groundbreaking full-body swimsuit. Full-body swimsuits help improve times compared to swimming without one, thanks to the “riblet” structure applied to their surface.
“Riblets” are a design modeled after the microscopic structures found on shark scales. Despite their large size, sharks move very quickly through the water to hunt for prey. Noting this, scientists hypothesized that shark scales must possess some special characteristics. Upon examining them under a microscope, they confirmed that tiny, rib-shaped protrusions were arranged in a specific pattern. Thus, the name “riblet” was coined by combining “rib,” meaning “rib,” with the suffix “let,” meaning “small.” Riblets work by altering the flow of water around a surface to reduce the drag acting on an object. A full-body swimsuit applies this structure to its surface. In fact, when swimming in a full-body swimsuit, water flows along the tops of the protrusions, forming small vortices. These vortices are the same phenomenon seen when water drains from a toilet, sink, or bathtub. To understand this principle, comparing the water flow on a flat plate to that on a riblet structure makes the difference easy to see.
On a flat surface, water flows across the entire surface, forming large vortices and, as a result, increasing drag. In contrast, on a riblet structure, small vortices first form in the grooves between the ribs, and then another set of small vortices forms on top of them. Through this process, the water flow remains more stable, and the formation of large vortices is suppressed, ultimately reducing drag. In other words, full-body swimsuits featuring a riblet structure are designed to reduce the large vortices caused by skin exposure and efficiently control water flow. Early studies reported that this structure is effective in reducing drag, and it is known to contribute to some extent to actual improvements in athletic performance. However, the rate of drag reduction varies depending on experimental conditions and the specific product, and certain figures that were widely publicized in the past cannot be considered universal standards. Considering that a significant portion of the drag generated during swimming originates from the body’s surface, it is clear that the discovery and application of the riblet structure represented a highly innovative technology.
As the saying goes, “Sports is science,” and various scientific principles are deeply embedded in sports. If both athletes and spectators understand these scientific principles, they will be able to enjoy the competition even more. However, full-body swimsuits sparked controversy because excessive performance enhancements led to equipment having a greater impact than the athletes’ own abilities; as a result, under current regulations set by World Aquatics, full-body polyurethane swimsuits of the type used at that time are no longer permitted in official international competitions. Nevertheless, research aimed at reducing drag is still actively underway not only in swimming but also in various other fields, such as large ships, aircraft, and submarines. This research is expected to continue, leading to the development of even more efficient and convenient technologies.
