For athletes, the Olympics are a chance to go for the gold and prove themselves against the best in the world…to live up to the Olympic creed: “faster, higher, stronger.” For the rest of us, the Olympics are mostly a chance every four years to cheer for our country and to watch sports that we’re not typically exposed to: archery, badminton, diving, rowing, etc.
One such sport that doesn’t typically get a lot of attention in the U.S. is field hockey. It’s played by both men and women at the Olympics, and the field hockey venues should be particularly interesting for those working in the athletic field management industry. Field hockey fields are constructed differently than most other sports fields, and the field hockey fields installed for the 2016 Summer Olympics in Rio (Brazil) look pretty unusual, too.
“They’ve played field hockey on a synthetic surface since the 1976 Olympic games,” says Paul Kamphuis, general manager with Polytan, the sports surface chosen for the field hockey venues at the Rio games. (Polytan also supplied the field hockey surfaces for the 2012 Olympics in London and the 2008 Olympics in Beijing.) The switch from natural grass to synthetic surfaces 40 years ago has dramatically increased the speed of field hockey, and changed the skill sets of the players, says Kamphuis, who is based in Melbourne, Australia – a country where the game is quite popular. And advancements in the surfaces used to play field hockey are continuing. For example, the yarn technology of the surface installed in Rio has been improved even from the 2012 Olympics.
The yarn is actually called a texturized monofilament, and boiling down the technology Kamphuis explains that as the yarn is extruded, it comes out like spaghetti. “So you get lots of small individual strands. As they’re extruded, those strands are stretched to give them strength and elongation. Then, before they’re wound together on bobbins to be used to tuft the synthetic carpet, they’re put through a texturization process, which basically involves squashing them into a small area where they get hot air blown on them.”
The curly, twisted shape that results is important to ensuring that, once the yarn has been tufted into the carpet, the resulting playing surface is nondirectional. “That’s really important, because we want to make sure that when a player hits a ball in any direction, it doesn’t get tracked by the surface and start to run in a single direction,” he explains.
The Polytan surface was manufactured using Dow’s “linear low density” DOWLEX polyethylene resins in the yarn, as well as Dow polyurethanes technologies for enhanced durability and more consistent play. “For athletes, the turf allows better ball control and shock absorption. It also helps eliminate injuries and allows high-level performance on the field,” explains Belinda Whitehead, spokesperson for Dow. “For Rio 2016, the citizens of Rio will largely benefit from the innovative playing surfaces…the park will remain as one of the main legacy projects for the city after the Games have concluded.”
Because of the very nature of the game of field hockey, the quality of the playing surface has a tremendous impact – for better or worse – on play. “It’s a sport that’s ‘ball-surface interaction dominant,'” says Kamphuis. In other words, the ball is on the ground a lot – at least 90 percent of the time, he estimates. What’s more, a field hockey ball is much smaller than, say, a soccer ball, and therefore is more susceptible to having its directionality altered by the surface. Put another way, a soccer ball rolls along on top of the surface, while a field hockey ball is actually in the fibers. So a field hockey-specific synthetic surface is much different than one that might be used for football or soccer.
For example, when it comes to elite field hockey surfaces, such as those installed in Rio, there is no infill as there would be on typical soccer and football fields. In field hockey, “you need to make sure the surface has as little impact as possible on how the ball travels across the surface,” notes Kamphuis. Short fibers help ensure that’s the case. The pile of the Polytan Poligras Platinum CoolPlus surfacing (designed specifically for elite field hockey play) installed in Rio is very short, only about 11 millimeters (less than half an inch) long; because of the texturization that curls these fibers, the effective height is even less, only about 8 or 9 millimeters.
The goal is not only to create a nondirectional surface, but also a fast one. At the Olympics, as is the norm at the elite levels of the sport, the field hockey playing surfaces will be irrigated before games. “There’s a misconception among the broader public that the surfaces are irrigated for player safety, so that the surfaces are less abrasive. That’s not entirely true. The surfaces are irrigated because it lubricates the yarn and makes the interaction between the ball and the surface different,” Kamphuis explains. On a dry surface, the field hockey ball tends to bounce more. On an irrigated surface, the ball skims across the surface, much like skipping a stone on water. “That makes the ball travel much faster,” he states.
In Rio, games will be played in back-to-back blocks, and the fields will be irrigated before each game. If it is particularly hot, irrigation may also be used between matches.
Another difference between field hockey fields and most other synthetic sports surfaces has to do with the subsurface construction. “I always use the analogy that when we’re building a hockey pitch, it’s sort of like building a parking lot. The construction up until the point we put the surface down would be very similar to what would be used in parking lot construction. We have a pavement that we construct on-site using crushed rock material and crushed aggregates. Then there’s asphalt surfacing that goes on top of that pavement, which improves the tolerances on the finished levels and the planarity (flatness) of the finished surface. With field hockey, there are very tight tolerances,” Kamphuis emphasizes.
Like on a golf green or a billiard table, the slightest irregularity can impact how the ball rolls. Finally, a curb surround holds the asphalt layer in place and a drainage system collects water.
One final attribute that differentiates the Rio field hockey fields from most other synthetic sports surfaces are the vibrant colors: blue with light green surrounds, resembling the flag of Brazil. Blue playing fields (with pink surrounds) were used at the 2012 London games. “In the U.K., it was dubbed the ‘Smurf Turf,'” says Kamphuis with a laugh. Jokes aside, there are practical reasons the color was selected and used again. “The reason the blue turf has been chosen is for contrast purposes,” he explains. “The blue background provides a much greater contrast against the ball, which helps for spectators at the venue and for broadcast on television.”
Kamphuis says that field hockey is not alone in preferring a non-green synthetic playing surface. While synthetic surfaces have traditionally been green to mimic natural grass, he says there is now a greater willingness to use other colors, especially when they can improve visibility for both athletes and spectators. “It fits in with a trend that’s been observed in some other sports, such as tennis, where many hard surface tournaments have gone to blue courts, which provides a much brighter contrast against the yellow ball.”
Kamphuis acted as project manager for Polytan in Rio, where the company’s responsibilities included supplying and installing the playing surfaces, and playing a role in the design of both venues. (There’s always two venues at the Olympic Games: a competition venue and a training venue, he explains.) “We also provided an on-site quality management/project management role, as well. Hockey is not a sport that’s popular in Brazil, so there’s not a lot of expertise in what’s required for hockey field construction,” Kamphuis adds. It was crucial, therefore, to monitor construction to be sure that the fields were built in accordance to the strict design specifications and International Hockey Federation requirements.
A total of four and a half hockey fields were installed for the Olympics: two for competition, two for training and a half-size warm-up field. There were two existing fields at the competition venue, put in place for the 2007 Pan-American Games.
“But to be honest, when we got there, the fields looked like they hadn’t been used since!” Kamphuis marvels. Another older part of the complex was even worse, he adds: “I had never seen a sports facility so dilapidated.”
After the existing infrastructure was demolished, construction on the new venues could begin. In addition to the fields, new athlete changing facilities and grandstands were built. “My first trip to Rio was in October 2014; they had just started the site clearing at the competition venue,” recalls Kamphuis. Construction was complete by November 2015. (The training venue, at a different location, was constructed between August 2015 and April 2016.) Construction of the fields presented a fair number of challenges, perhaps chief among them Rio’s construction standards. “We went into this project knowing that the construction standards were maybe not what we would like them to be for an Olympic venue – we knew upfront that was going to be a challenge,” he states. “Hockey is a minority sport in the country, so there was little understanding of what was required.” First, it was critical to convince the field’s contractor of the importance of the very tight tolerances specified.
There was also a language barrier, he adds.
“In some of the early meetings when I was trying to explain some of the design concepts, there were some people from the 2016 Rio organizing committee who spoke English, but a range of people … didn’t speak any English. Trying to communicate in those circumstances was a challenge.”
Once construction began, a different translation was required. For example, Kamphuis and the other Polytan representatives needed to find local equivalents to the construction materials they normally specified. “There was no point in us specifying a specific grade of asphalt if that asphalt product was not available locally,” he explains. “We worked with architects and engineers within Rio to make sure we specified things that they had an equivalent for.”
Rio’s tropical location, prone to heavy rainfalls, also presented design challenges. Typically, Olympic-level field hockey pitches are designed with a very flat grade. “But very flat grades tend to mean that if you get very high rainfall, the water will pool on the surface. So we had to balance those two things out,” says Kamphuis. As a result, the pitches were built so that they slope out to the sides, and toward each goal, with a maximum grade of 0.4 percent. That’s still a pretty flat grade, so the fields were constructed with two layers of asphalt. “The top layer is quite thick, and it’s open-grade, porous asphalt, so we’ve basically incorporated into each pitch a water attenuation capacity. We’ve got a large volume within that asphalt storage layer that we can fill up before we see any water appear on the surface.”
Polytan will not be directly involved in maintaining the hockey fields during the Olympic competitions, but did specify the protocols and equipment to use. “The extent of maintenance that will be done during the Games is far greater than what would be done on a regular hockey field. The goal is to keep the field as clean as possible for television broadcasts,” says Kamphuis.
With high-definition technology, any piece of trash on the surface will be visible. “And hockey players can be a really dirty lot! You tend to find a lot of hair bands, hair clips, bandages, those kinds of things on the surface, so the pitch will be groomed, mostly to keep the surface clean,” Kamphuis says.
SportChamp (from SMG) grooming equipment will be used daily during the Olympics. “It’s the same as is used on what’s known as third-generation artificial turf fields with sand and crumb rubber; it just has a different attachment on the front for grooming an unfilled surface,” he explains.
While a clean appearance is important for television, cleanliness is essential to ensuring field performance and longevity, he notes: “If anything is left on the surface that can break down and get into the pile, it impedes how the water travels through the surface. Particularly organic matter can break down into finer material, which then sits inside the pile structure…you get issues like algal growth.”
Kamphuis will be watching the Olympics with a keen eye on how the field hockey field looks and performs. He hopes that’s the last thing the players are worried about: “The whole idea is that the players don’t notice the surface; that all they’re focused on is the game.”