The Often - Overlooked Importance of Shock Pads Underneath Synthetic Turf
By: Dan Sawyer

The features and benefits of having a synthetic turf athletic field have been well documented in numerous articles over the years. As the market continues to grow and the technological advances continue to minimize the differences between natural and synthetic turf from a performance standpoint, it’s time now to look at making these playing surfaces safer. A new trend has arisen that is equally important, but that is less understood—the use of “shock pads” under synthetic turf.

Synthetic turf has come a long way from the original nylon carpet commonly known as Astroturf. Gone are the days of hard landings and abrasive fibers, to be replaced by today’s more advanced infilled turf systems. In a way it makes sense: as the synthetic fibers try to mimic a blade of grass (that won’t “die” under heavy use), and a rubber and sand infill designed to simulate the “soil” for the plastic grass.

There are several advantages to the infilled turf systems:

First, the infill improves traction for the athlete. Virtually gone are the days of “turf toe” when athletes tripped due to their foot actually “sticking” to the turf.

Second, the rubber used in the infill acts as a cushioning layer to act as an impact-absorbing material, so the fields are not as hard as the old non-infilled carpet.

Third, the new fields “feel” more like a natural grass field than Astroturf of yesteryear.

But as much as these turf systems have improved, there are still some drawbacks, most of which are caused by the natural aging process of a synthetic turf field.

The infill compacts and hardens over time, especially if the field is not maintained. This can be particularly challenging in a park setting where maintenance is sporadic at best. Infill compaction results in the surface stiffening. This causes rising impacts and reduced safety to the players, and soccer balls that bounce higher as time goes by.

Also, the infill tends to “splash” when a ball hits it or a player falls on it. This is more of a nuisance, yet one of the most common complaints by the people who play on them. When compared to the “slit film” fibers used in systems from 1999 to 2006, the use of monofilaments increases the splash levels.

Related to splash, the infill also tends to migrate, so the level becomes very thin in areas like goalmouths and at the 50-yard line of a football field.

But today, technologies and systems exist that solve some of the downsides of the infill turf, and even further improve the overall performance and safety of the field. Plus, they can significantly slow the “aging process” that is inherent in these newer infilled synthetic turf fields.

The primary addition to any good synthetic turf system is the use of a shock-absorbing layer underneath the turf. Shock pads typically reduce infill compaction, reduce infill migration, reduce g-max (an ASTM measure used to determine the likelihood of a head injury), and provide a safety component in the event maintenance is irregular. They can also improve drainage and give your synthetic turf field a more “natural turf” feel of play. And, for one to get a better vision of the effects of these “shock pad” systems, one has only to look at the more mature and arguably more sophisticated European synthetic turf market.

The primary reason that Europe has grasped the benefit of putting shock pads under synthetic turf is due to the rigorous test standards implemented by FIFA, the world governing body for soccer. The standards developed by FIFA in conjunction with independent test labs test a synthetic turf system under multiple criteria that go far beyond just impact absorption, and investigate how fields age with time, and the effects of that aging on the sport and even the athletes themselves. In other words, it is a far more comprehensive set of test criteria that has driven innovation in the synthetic turf market to strive toward the ultimate goal of a synthetic surface that behaves and performs like a stadium-quality natural grass field, not just on day one but also in year five.

One thing these test methods illuminated is that the use of a shock pad under the turf greatly mitigates the problems associated with infill compaction, field hardening, and degradation in performance over time. More recent advancements in shock pad technology are now yielding results of safety, performance, and longevity never before seen in the industry. So, the question becomes not whether a shock pad is necessary, but rather how to choose the proper system.

In Europe, shock pads come in a variety of materials, including rubber, recycled foam, composites, and molded foamed plastics. Most of these systems were pre-existing, but due to the size of this growing market, they have been “adapted” for use under synthetic turf with varying results. But there are several criteria that can be used for all of them to determine their viability to the turf system you select.

1. Impact Absorption vs. Deformation
This may be the most difficult concept to grasp, yet it will have the most noticeable effect on the playing quality of the field. This quality relates to how much a material must “compress” in order to lower the g-max to acceptable levels. The more compression in the shock pad, typically the lower the g-max will be. However, a greater compression of the shock pad also results in a field that will feel “softer” to the athlete. This may be acceptable for children, but any young adult or adult level player may not like the “slowness” of the field and object to feeling “tired” after extended playtime. Ideally, a material would lower g-max with the minimal amount of compression in the material so the field feels “normal” yet offers the lower g-max and safety component many owners want.

2. Sustainability
One of the largest national trends occurring across all business sectors worldwide is a renewed focus on sustainability, and a solution to the end of life of a given product or material. This does not mean throwing it away or land filling. So, even though a shock pad may have originally been from recycled it materials, the new end-of-life scenarios may be a landfill or burning. Costs associated with this end-of-life solution will be burdened on the buyer, so beware. Ensure that the products you chose have a plan of what to do at the end of their life that satisfies your local near and long-term environmental criteria as well as your budget.

3. Drainage
Since the use of any product under the turf will affect your field drainage, demand the proper testing results that will demonstrate that the use of a given pad system will not adversely affect the drainage of the field. Infill turf was originally designed to work without a shock pad, so whether the synthetic turf uses a punched hole backing or a “scraped” backing, it will need to work as a system with any shock pad. Demand that the system you chose is pre-tested to recognized drainage standards and meets your local rainfall requirements.

4. Reference Fields
Just like you will want to do your due diligence on fields that have used your potential turf system, do the same research on fields using the shock pads considered. Find out about installation times, whether they are weather dependent, thermal expansion and deformation under the turf. If you find out the shock pad changes under climatic conditions after the turf is laid down, you are in for a disastrous field replacement.

A synthetic turf field is a considerable investment, and with the increasing longevity of newer monofilament fiber turfs, it is an investment that will affect many people over a long time. Whether those effects are positive or negative will depend on the overall system chosen. Knowing that synthetic turf does change over time, understanding your maintenance constraints, and that a drainage or safety problem could result in litigation, field replacement or worse, considering the proper shock pad for your system is an essential component. 

Dan Sawyer is president and chief executive officer of Brock International, www.brock-international.com.

Product Roundup

 Star Liner from Pioneer Athletics
Pioneer Athletics has introduced Star Liner, the newest addition to their fleet of high-quality athletic field striping equipment. Star Liner is a compact and portable, easy-to-use, electric field liner that maximizes striping time with a long-lasting battery and “Plug & Stripe” technology. Just “plug” the ready-to-use container of Star Stripe paint into the Star Liner and stripe away. Star Stripe paint features Halogen 2000 optical brighteners, giving you unbeatable lines that stand-up to tough play and weather. 
www.pioneerathletics.com

Daktronics Outdoor LED Video Displays
Daktronics offers a new line of affordable video displays. The new outdoor LED video displays show animations, statistics, advertisements, and live video in full color. Video displays provide many advertising opportunities for schools with the ability to promote local sponsors. Displays also provide opportunities to communicate recent and upcoming events to the crowd. Entertaining the crowd with animations, informing fans and displaying the next game date and time is possible with the new Daktronics video displays.
www.daktronics.com

SportsGrass by ForeverLawn
SportsGrass by ForeverLawn is a high-performance, all-weather synthetic turf that truly enables your athletes to play at a higher level. Offering unmatched performance, a natural underfoot feel, and a playing surface second to none, SportsGrass by ForeverLawn is the ideal solution. SportsGrass offers a realistic grass-like appearance and performance that can be played on all year round in any type of weather. Antimicrobial protection is available to help create a cleaner, safer environment for your players. 
www.sportsgrassturf.com

Qualite Sports Lighting
Qualite Sports Lighting systems incorporate efficient sports lighting fixtures. Their systems, with fixtures pre-set specifically for your field, provide optimum uniform light with superb spill light control. A safe and enjoyable environment is created for both players and fans. Available with every Qualite Lighting system is their patented Maintenance Diagnostic System (MDS), which reduces lifetime maintenance costs and allows testing from ground level.
www.qualite.com

Bison Soccer Goals
Bison has every size of soccer goal needed for the playground and the playing field. Bison ShootOut portable aluminum soccer goals come in five sizes, from 9' Bantam to 24' Competition. The aluminum crossbar and posts can be 4" round, 4" square or 2" x 4".  All these goals feature QwikTrack net attachment that eliminates velcro, wire clips, welded-on or screwed-on net attachment systems and a backstay attachment that eliminates corner weld failure commonly caused by moving the units around the field.
www.bisoninc.com

Electra Tarp Deluxe Football Sideline Covers
Electra Tarp deluxe football sideline covers provide maximum protection to your field while allowing your grass to breathe. Constructed of a 12-ounce white, non-woven Geotextile, this material has a non-slip surface and is mildew resistant. It comes with grommets every 3 inches around perimeter and a reinforced vinyl-hemmed edge around the perimeter. Ten-inch stakes also are included with each sideline cover. Covers are available in 20 colors.
www.electratarp.com

Pilot Rock Benches
Pilot Rock benches provide team seating for all outdoor sports. Benches are available with or without backrests. The all-welded frame is hot-dipped galvanized for maximum protection from the elements. The athletic benches can have either portable or stationary installations, and they come in several lengths. The seat/back material can be wood, aluminum, recycled plastic, or vinyl-coated steel in team colors. The Pilot Rock product line includes picnic tables, pedestal grills, park and street site benches, bike racks, trash and recycling receptacles and lids, lantern poles, and more. 
www.pilotrock.com

Goal Sporting Goods
Goal Sporting Goods allows schools to build a custom field with team pride and a distinct home field advantage. The customizable personalization product line includes everything schools need to build an entire field based on team colors or sponsors. Goals, nets, field marking paint, corner flags, bleachers, and benches can be colored and personalized to match a school’s team colors and logos. 
www.GoalSports.com

Brock Performance Base
Brock Performance Base is a patented polypropylene-based material that promotes drainage, the environment, and player safety and performance. Designed to replace the costly layers of stone traditionally used to build an athletic field base, Brock installs quickly and efficiently, requires no infield drainage system, and reduces pollution, fuel consumption, and on-site energy usage up to 55 percent. Brock also drains water from the field quickly, allowing your athletes access to the field in a variety of adverse conditions.
www.brock-international.com