The Engineering Behind Japanese Gymnastic Gold

Unlikely Outcome of Russo-Japanese War

When we think of sports equipment manufacturers, the companies that produce sports shoes, balls, rackets, and gloves tend to come to mind first. However, there are also manufacturers that are responsible for producing everything that is found in a gymnasium. The best-known is Senoh, a Chiba-based manufacturer that offers a comprehensive range of sporting equipment While Senoh is best known for its school gymnastics equipment such as mats and vaults, it was its initial success with basketball hoops and volleyball net supports that led it to progressively expand its range to include the equipment found in gymnasiums and stadiums.

Founded in 1908, Senoh was initially an owner-operated purveyor of agricultural equipment. As Senoh Spokesperson Hiyoshi Nonoko explains, the catalyst for the company’s expansion into sporting goods was a surprising one.

“Our founder, Senō Rikizō, served in the Russo-Japanese War. He was inspired to start making exercise equipment after being struck by the difference in size between Japanese soldiers and their Russian counterparts, and feeling that the Japanese needed to improve their physique. Senō was born in Tottori, as was Mihashi Kikuo, who is known in Japan as the ‘father of gymnastics’ for his work in establishing the foundations of physical education in schools. Mihashi told Senō that he was training PE instructors and wanted Senō to produce gymnastics equipment for him to use. I understand that this was a major factor in Senō’s decision to start producing this equipment,” says Hiyoshi.

At a time when Japan had no concept of sport, let alone a word for it, Senoh was making wall bars (the ladder-shaped bars in gymnasia that are used for chin-ups and climbing practice) and other gymnasium essentials, most of it for training soldiers. High bars and pommel horses were also an important part of the company’s initial product range.

Senoh is accredited internationally as a manufacturer of equipment for gymnastics, volleyball, basketball, badminton, and paravolley competition. The only Japanese sporting equipment manufacturer to hold multiple international accreditations, Senoh has supported many international and domestic sporting competitions.

All the equipment in this basketball court at Fukuoka’s Ōhori High School was manufactured by Senoh. (© Senoh)

Senoh was also the sole supplier of equipment to the gymnastics, volleyball, beach volleyball, sitting volleyball, and wheelchair basketball events at the Tokyo Olympics and Paralympics in 2021. Of these, gymnastics is the sport with which Senoh has the most experience—indeed, the firm made the gymnastics equipment used at the 1964 Olympic games in Tokyo, too.

Japan excels at gymnastics. In fact, Japanese Olympians have won more medals for gymnastics than for jūdō or swimming. However, not many people know about the role that Senoh’s obsession with excellence had in helping Japan to become a gymnastics superpower.

Pivot Makes a Difference

Responsible for Japan’s largest number of gold medals, the horizontal bar (or high bar) is one event at which Japanese competitors particularly excel. The Senoh bar that the members of the Japanese national team use for day-to-day practice sports a feature not found in bars made overseas: the universal pivot. Invented in 1988, the universal pivot debuted at the World Artistic Gymnastics Championships in 1995.

Nigorikawa Yasushi, an engineer from Senoh’s development headquarters, describes the design and development of the high bar:

“You can think of high bars manufactured by overseas manufacturers as being supported by pins that pass through their vertical supports. Senoh bars, on the other hand, feature caps between the supports and the bar that enable the bar to rotate freely. This is known as a universal pivot, and is a bit like the ball joints found in cars,” says Nigorikawa.

It is because of the universal pivot that Senoh high bars move differently from overseas brands that are supported by pins. When a gymnast performs giant swings (or “giants”) on an overseas-produced high bar, gravity and repulsive forces will cause the bar to follow an elliptical path. The Senoh bar, on the other hand, flexes evenly in all directions, thereby allowing the gymnast to move in a more circular path.

“The universal pivot was invented 35 years ago, so no detailed records remain, but it was probably developed in response to a request from gymnasts to be able to rotate more smoothly,” says Nigorikawa.

However, gymnasts on national teams generally perform their day-to-day training on equipment that is produced locally or in nearby countries. The equipment used in international competitions also tend to be manufactured in the host country or a nearby country, due to the time and expense required to transport it.

The Fédération Internationale de Gymnastique has attempted to reduce the differences between manufacturers and models through the introduction of stringent specifications and accreditation testing. However, top-level gymnasts are sensitive to even the most subtle of differences, and therefore often perform better on the brand of equipment they use for their day-to-day practice. It follows that Japanese gymnasts are naturally more familiar with Japanese-made equipment, that is, Senoh’s.

The equipment used at Japan’s 2022 national student gymnastics championships was also manufactured by Senoh. (© Senoh)

Giving Japanese Gymnasts an Advantage

However, familiarity is not the only reason that the Japanese gymnastic team prefers Senoh equipment. In aiming to overcome the physical disadvantages faced by Japanese competitors, Senoh has consistently produced equipment that allows Japanese gymnasts to play to their fortes. As is the case in many sports, Japanese gymnasts tend to be smaller and less powerful than their European and US counterparts. However, Japanese gymnasts have long maintained top-class performance by compensating for these disadvantages with superior technique. In fact, the country’s entrants in international competitions are often praised by overseas competitors and reporters for their excellent form. The coach of the national athletics team is on record as attributing this to the fact that Japanese gymnasts grow up training on Senoh high bars, which move in regular, circular paths.

When the Senoh universal pivot debuted in 1993, something interesting happened at those gymnasiums that had upgraded to the new bar. All of a sudden, children that had been unable to perform giants were doing them.

A closeup of a Senoh high bar showing the part that contains the universal pivot. (© Senoh)

As a company that values the insight of athletes, Senoh employs many former sportspeople. Shūtō Fumiki of the company’s sales division began gymnastics at a very young age and continued until university. He explains the universal pivot:

“High bar routines exploit the flex of the bar. If the bar is too stiff, it will tend not to flex under the light weight of a child, and this makes it difficult for children to master these routines. The universal pivot solved that problem. On the high bar, you need to use centrifugal force to your advantage, because you won’t be able to perform the routine with your own strength alone. Unlike overseas brands, which flex in an irregular, elliptical path, bars equipped with universal pivots are designed to rotate in a perfect circle, allowing even child gymnasts to produce more centrifugal force. This makes these bars better for mastering the giant swing,” says Shūtō.

Japan’s gymnastic team did not win any gold medals at the Atlanta (1996) or Sydney (2000) games, causing Japan to fall significantly behind China and Eastern Europe. However, the child gymnasts of the day attained excellent form using Senoh bars equipped with universal pivots. Before long, Japan had returned to its former glory as a gymnastics superpower. Indeed, Japan’s reputation in this field can be attributed to its top-class athletes and the Senoh equipment that allows them to express their talents to the full.

Senoh’s main focuses are actually volleyball and basketball. In terms of sales, gymnastics is a niche market. (© Senoh)

(Originally published in Japanese. Banner photo: Hashimoto Daiki performs in the final of the men’s individual all-round event at the Tokyo Olympics on a Senoh high bar. Initially behind his rival by 0.467 of a point, Hashimoto went onto win gold on July 28, 2021, at the Ariake Gymnastics Center. © Jiji.)