The more upright fibers are believed to affect ball roll and are often selected when the field is used predominantly for soccer. Unlike slit film fiber, where a group of fibers is tufted through the backing, monofilament fibers are individually stitched and then glued onto the backing.
The material that takes up the space between the grasslike fibers is the infill, which typically contains either rubber or a combination of rubber and silica sand. In most current synthetic surfaces, the infill material is installed to a depth of 25 to 40 mm of the total 40 to 70 mm of fiber length.
The crumb rubber typically is a product of recycled vehicle tires that are either ground or cryogenically frozen and shattered and then sized to granules between 2 and 3 mm. The benefit of rubber as a material is its high elasticity and resistance to weathering. Turf systems rely on this crumb rubber to provide cushioning to athletes during play, especially when a pad layer is not present. Other manufactured granular infill materials include elastomer, polymer, or organic substances such as coconut fiber, cork, and ground walnut shells.
These alternative materials may be used more commonly in the future. Carpet sections with grasslike fibers are generally manufactured in foot 4. During installation, these sections are either stitched or glued together. This creates seams in the playing surface, which have been a concern. Historically, first-generation fields were thin, and small discrepancies in surface grade where the seams joined together created a concern for tripping or entrapment and therefore possible injury.
Playing surface planarity due to seams in third-generation turf is less of a concern because the infill is continuous over the top of the backing seams. However, the method used to join seams and, particularly, the method used to install logos, numbers, or other permanent field markings, termed inlays , can result in variation of the planarity of the carpet backing and thus result in varying infill thickness across the surface.
This is best accomplished by removing the backing of the existing carpet before installation of an inlay. Attaching the inlay backing over the existing carpet backing is not suggested as this necessitates a thinner layer of infill in those locations to create a planar playing surface. One of the perceived benefits of synthetic turf over natural turfgrass is that synthetic turf is maintenance free.
This is a misconception; synthetic turf requires regular maintenance, which should be specified by the manufacturer. Generally, turf warranties are contingent on the performance of this regular maintenance. Several routine maintenance practices should be performed.
To raise matted-down fibers, brooming with a nylon bristled brush and raking with spring tooth tines is typically accomplished by pulling devices across the surface in multiple directions using a utility vehicle Figure 2. The frequency of these operations depends, but may be required as often as weekly on surfaces receiving daily use. Besides raising matted-down fibers, brooming and raking can also loosen the top layer of infill material. Other devices using rotating tines or spikes can be used to penetrate, mix, and loosen the infill material to a greater depth.
These are used less frequently, perhaps only 2 or 3 times per year. A maintenance practice of particular importance and observed to be lacking on most third-generation infill systems is the periodic replacement of lost infill. Over time, the infill thickness can be reduced, possibly resulting in an increased risk of athlete injury by increased surface hardness, traction, or both. Infill depth should be maintained to manufacturer specifications and routinely monitored, with inspections and results recorded.
A sample spreadsheet to aid in tracking and suggested test locations is available. To increase thickness, manufacturer-approved infill can be added using a commercial topdressing device common in turfgrass management. Small amounts should be applied followed by brooming to work the infill into the pile fiber. This process may need to be repeated to reach the required thickness.
A professional vendor using specialized equipment may be required for fields that have not received regular infill replenishment for a number of years or where the pile fibers are heavily matted. The buildup of paint can result in excessive surface hardness.
Paint buildup should be monitored, and periodic removal of paint residue is suggested. The frequency of paint removal varies depending on the application methods, but removal after 4 consecutive applications can be used as a guide.
Paint removal can be laborious, but new paint technologies and new removal equipment have been developed to aid in more efficient removal. Debris, while not unique to synthetic surfaces, is also a concern that requires attention. Surface debris such as garbage and leaves can be removed with a blower, sweeper, or vacuum. Commercially available towable magnets are used to remove metal debris such as parts of helmets, jewelry, paper clips, and construction materials Figure 4.
A Magnetic drag and B subsequent metallic debris recovered on the bottom of the drag. Other contaminants, including items such as chewing gum, tobacco, sunflower seeds, oil, and other organic contaminants, can be removed mechanically or chemically at the recommendation of the turf manufacturer.
Body fluids should be diluted and flushed from the surface with water. Antibacterial solutions are available for disinfection of the surfaces, but laundry detergent and ultraviolet light can be comparably effective. One of the most important benefits of modern synthetic surfaces is the increased usability of the facilities.
This is particularly important in stadium settings, where the venue hosts events such as concerts, trade shows, or nonturf sports such as basketball or hockey. To maintain a playable surface, it is important that the synthetic turf is protected during these events.
This protection was traditionally accomplished using plywood-type flooring overlaid on the synthetic turf. However, a variety of engineered polypropylene and metal systems are now available, some of which will support the weight of large cranes and other heavy construction traffic. The goal of these systems is to distribute loads across the surface to prevent infill and gravel base movement.
Playing surfaces take on an important role in player health and safety, as evidenced by the common incidence of noncontact injury across many sports, which often involve some degree of interface between an athlete and the playing surface.
Dating back to the s, research has shown reason for concern over injury rates on synthetic turf. Many of the studies published to date report on playing surfaces that are no longer routinely used and are not subject to consistent maintenance practices. There is a mechanistic rationale to assert a causal link between play on a synthetic surface and increased risk of lower extremity injury, specifically within sports that involve heavy loading of the surface, such as soccer and American football.
Because synthetic surfaces lack this ability to release a cleat in a potentially injurious overload situation, they have the capacity to generate greater shear force and torque on the foot and hence throughout the lower extremity.
The epidemiological assessments that have been published examining a differential injury rate between synthetic and natural turfs are generally supportive of this hypothesis: Studies that focus on lower extremity injuries caused by a twisting or shearing mechanism typically show greater rates of injury on synthetic versus natural turf.
These findings are consistent with previous NFL studies 16 as well as with the majority of studies among collegiate football players. While these studies, among others, have begun to sort out differences in some athlete populations, a full understanding of the difference in injury risk is complicated by the size and power of the studies as well as differences among sexes, sport, level of competition, weather, footwear, and variations in the playing surfaces themselves, including maintenance.
In addition to the lower extremity injury concerns discussed, 21 head injuries, infectious diseases, heat, and the potential for carcinogenic effects of the playing surface material have all been studied to some extent with regard to synthetic turf surfaces. Head injuries in athletes are a serious concern. For a given effective head mass during a vertical impact to a surface, the head will experience greater peak acceleration when striking a harder surface than a softer one.
The temperature of synthetic turf playing surfaces is an important factor to consider. Thus, the surface temperature is driven by the total amount of solar radiation. Different methods have been tested for cooling these surfaces. The health effects of the material in third-generation synthetic turf components have been the subject of much debate.
In several states, advocacy groups have proposed a moratorium on these materials until they can be proven safe for players. The main concern is carcinogenic risk related to the exposure to harmful chemicals present in the rubber infill. However, it would be prudent for building operators to provide adequate ventilation to prevent a buildup of rubber-related VOCs and SVOCs at indoor fields.
Birkholz et al 3 demonstrated that crumb rubber poses minimal risk. Zhang et al 56 analyzed samples of infill rubber for the bioavailability of polycyclic aromatic hydrocarbons PAHs and several metals.
They showed that the rubber infill, especially on newly installed fields, contained levels of PAHs that were above health-based soil standards; however, the level of PAHs was noted to decrease as the fields aged.
PAHs in this study had zero or near-zero bioavailability. Lead metal was detected in the samples and was shown to have some bioavailability. Air quality with rubber infill has been another concern. Dye et al 11 found that indoor facilities have detectible levels of almost chemicals and particulates that could be identified and another chemicals that were detected but not able to be identified.
They do not, however, address the effect these chemicals may have on human health or whether these chemicals are similarly detected on outdoor fields with open air.
They noted that the urine samples for PAH metabolites were minimal and within the ranges of PAHs taken up from environmental sources or diet. While the majority of studies conclude that there is little to no elevated health risk associated with rubber infill, it will be difficult to prove without a doubt. Because of this, it is likely that studies will continue on these synthetic fields to further assess athlete safety.
Media outlets have raised concern about the development of skin infections in players exposed to synthetic turf. Two studies have focused on separate outbreaks of methicillin-resistant Staphylococcus aureus MRSA and examined the role of third-generation synthetic turf on infections.
They noted that all the infections occurred at areas of turf abrasion. Both of these reports included teams that had third-generation synthetic turf on their home field, and while both concluded that turf abrasion sites could facilitate infection due to the break in skin, neither study implicated the source of the infection as the playing surface itself. Both studies raised concern for poor sanitary conditions in the associated facilities locker rooms, etc as well as skin-to-skin contact between players as the likely source of the infection.
McNitt and Petrunak 31 found no S. Of note, there was generally less total microbe load on synthetic turf compared with natural turfgrass. This study also tested for the presence of S. The cause of a lack of viable S. On outdoor surfaces where the bacteria were exposed to ultraviolet light from the sun and to high surface temperatures, the population of bacteria fell quickly, regardless of whether a control agent was applied.
Indoors, the bacteria survived for multiple days, but the number of surviving bacteria decreased significantly with time.
Antimicrobial treatments and laundry detergent decreased the survival rate of the bacteria present on indoor surfaces. Third-generation infill systems with polyethylene pile fiber have been shown to be considerably less abrasive than first-generation nylon systems, although both are more abrasive than well-maintained natural turfgrass. Modern synthetic turf is far different than when originally introduced and in large part has improved in both structure, quality of components, and ability to be consistently maintained.
It is important for sports medicine personnel to be familiar with playing surface issues as they are often treating athletes at the time of injury on these surfaces and may also be important advocates for improved synthetic turf maintenance practices. These surfaces require routine and targeted maintenance at all levels of play.
Early AstroTurf baseball fields used the traditional all-dirt path, but in the early s, teams began using the "base cutout" layout on the diamond, with the only dirt being on the pitcher's mound, batter's circle, and in a "sliding box" around each base. With this layout, a painted arc would indicate where the edge of the outfield grass would normally be, to assist fielders in positioning themselves properly.
The biggest difference in play on artificial grass was that the ball bounced higher than on real grass, and also traveled faster, causing infielders to play farther back than they would normally, so that they would have sufficient time to react.
The ball also had a truer bounce than on grass, so that on long throws fielders could deliberately bounce the ball in front of the player they were throwing to, with the certainty that it would travel in a straight line and not be deflected to the right or left. In , Franklin Field , the gridiron stadium of the University of Pennsylvania, Philadelphia, Pennsylvania, switched from grass to artificial turf.
Also home of the Philadelphia Eagles, it was the first National Football League stadium to use artificial turf. In , Gillette Stadium , the football stadium of the New England Patriots and the New England Revolution, switched from grass to artificial grass due to the conflict of poor weather and hosting many sporting and musical events at the stadium. It is one of 13 National Football League stadiums that have turf instead of grass fields; the Patriots, Giants and Jets who share a stadium and Bengals actually switched from AstroTurf to natural grass before reverting to a next-generation artificial surface.
All eight stadiums in the Canadian Football League currently use artificial grass, due to that country's northern climate.
This trend has been driven by the dramatic improvement in the quality and variety of available synthetic and artificial grasses, the reduced cost of maintenance and care compared to natural grass, and the realisation that artificial lawns can be a significant water conservation measure in areas where water usage is a concern. Source: Wikipedia, May Shop Now. It looked good, but it was not player-friendly.
So, there were a few obstacles to be overcome before we could be well served by the specialised sports turfs of recent times. As with any great idea, from sketchy beginnings, improvements created demand and demand drove improvements. Also home of the Philadelphia Eagles, it was the first National Football League stadium to use artificial turf.
Early s: Synthetic grass fields began to be used for hockey. The new generation of sports turfs available today provides a superb surface for playing sport on. Revolutionary technical advances in the materials used for sports surfacing systems led to the production of softer, non-abrasive synthetic grass blades, which were then manufactured with high-performance backing materials.
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