With play, infill moves. It gets kicked out from the most heavily used areas to the least used areas of the field. This phenomenon, called “infill migration,” means that the areas with the least amount of infill to reduce impact forces are also the most used. Danger arises when shock is absorbed solely at the point of impact and returned directly to the player. Too much force transmitted to the player (particularly the neck and head) has the potential for life-threatening consequences.
Disperse the impact! When a player falls on the turf, it is vitally important that the force of the fall is spread over a wide area.
The Industry’s Solution:
There are two industry-standard methods to spread the impact — infill and shockpads (or a combination of the two). Infill is the particulate material brushed into the fibers of the system. There are many options for infill, but the most common material used to attenuate shock is SBR (ground up recycled tires). Shockpads are installed underneath the turf carpet. There are many choices out there. They come in a range of materials and absorb and spread impact to varying degrees.
All Too often, turf companies respond to clients’ desire for a pad by sliding a pad under the same old turf systems. This is overkill and wasteful.
Each AstroTurf system will provide excellent shock absorption at installation, and every field is guaranteed to stay within safe limits throughout the life of the warranty. However, the best playing and safest fields go further — they promote uniformity across the field and over time.
For the most uniform fields with the best player protection, AstroTurf recommends use of pads and/or RootZone — preferably both!
RootZone — To combat infill migration, AstroTurf’s premium 3D Product Line includes a RootZone. The RootZone acts like a net to encapsulate the infill and reduce its migration, delivering more consistent shock absorption across the field and over time. Infill stability is not just crucial to shock attenuation. It has a drastic impact on foot release and durability over time as well! The RootZone comes at a premium, but its benefits are legendary.
Pads — Shock pads are separate, elastomeric materials such as foam, rubber, beads or fibers bound together with a strong adhesive that are placed underneath the turf surface. Many pads have been available for decades, while the size of the turf market today is attracting newer technologies. Our laboratory tests pads exhaustively before approval for field use.
An intelligently designed SYSTEM will incorporate both solutions in a shorter, denser pile — providing more fiber (for enhanced return on your investment) in a cost-effective configuration (especially when using alternative infills).
Cleat lock! Also known as foot fix, the greatest orthopedic risk to players arises when the cleats become trapped in the surface. As players run, pivot, and move, kinetic forces are generated. This force must be released. Ideally, this happens when the foot is released from the playing surface. If the foot is not properly released or the cleats become trapped, the potential for injury to the lower extremities rises as the force looks for the weakest link through which to escape.
Optimal traction! A surface should be engineered to efficiently release the shoe across a range of cleat designs. At the same time, the turf system should provide adequate traction to prevent players from slipping and sliding on the surface and to give them the speed they need to win. The ideal surface should balance these needs.
The Industry’s Solution:
The industry’s approach to lower limb protection is mixed. Many companies place little emphasis on foot release and merely point out that a synthetic field will inherently provide more uniform footing than many of the poorly maintained natural fields their customers currently play on.
Others tout misguided philosophies. They claim that because dirt is heavy, a heavyweight infill layer is the solution. Unfortunately, the science doesn’t support that notion. The only independently funded research on this type of system was conducted by the NFL. That study found heavyweight infill resulted in 67% more ACL sprains than natural grass! This could be because heavyweight infill, especially with high sand content, tends to compact, which can trap cleats.
RootZone — AstroTurf’s RootZone, found in the 3D Product Line, specifically addresses cleat release. This crimped layer of fibers keeps the infill in place, reducing infill migration and compaction. The result is optimal cleat release and less torque transmitted to knees and ankles.
In fact, research by Michigan State University found that the RootZone was “the most influential variable” in reducing torque because the RootZone “limited cleat contact with the infill and provided a less compacted… infill layer.” These findings are statistically significant and the research is independently funded!
Over the years, heavy metal and carcinogen content in synthetic turf has been called into question. However, all fibers have fewer than 50 parts per million (ppm) of lead, less than the Consumer Product Safety Commission’s limits for children’s toys (100 ppm) and household paints (90 ppm). Also, crumb rubber infill has undergone rigorous academic scrutiny — dozens of independently funded studies have examined crumb rubber’s health and environmental effects; none has found cause for concern. Customers must make selections they feel confident will safely provide adequate shock attenuation. We urge our clients to trust the science.
While we are certain about the safety of crumb rubber, we also offer options to our customers who are reluctant to install crumb rubber. There are many substitutes for crumb rubber, though all come at a higher cost than traditional SBR. Owing to AstroTurf’s long history as the leader in non-filled turf technology, AstroTurf has developed a line of turf technology named for AstroTurf’s 50th (golden) anniversary — The Golden Series. These products are specifically designed as rubber-free systems engineered for great shock absorption and durability without rubber in a cost-effective configuration