Know Your Field, After All it\'s Your Turf

by: Rod Smith
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When it comes to player safety, what is your most important piece of equipment?

As a coach you’ve been taught to properly fit helmets and shoulder pads, both essential tools that can keep players safe. But what about your field? How safe is it?

Without proper care and maintenance, your field can cause severe injury – just like ill-fitting helmets or pads. With overuse – repeating drills in the same place – and misuse – using a field already in poor condition or beyond its limits – football fields become even more dangerous. Because of the brutal nature of the game, when your players step on the field they are already at risk – so why compound the situation by sending them into competition on an unsafe playing surface?

In some sports, it is the participants who assume responsibility for the field of play. For example, in golf it is customary to replace your divots. For those not familiar, divots happen when a golfer strikes the ball and the club removes a small lump of dirt and grass. To replace a divot, a golfer simply places the grass and soil back in its original spot and tamps it down with his foot. While golf’s slower-paced atmosphere lends itself to such a traditional practice, the same cannot be said for football. In this fast-paced, naturally destructive game, football players, much like golfers, unintentionally cause irregularities in the turf, but are unable to repair the field at a similar pace.

In golf, replacing divots gives the surface a chance to repair itself. A healthy, consistent surface makes for a safe field – one good for athletes. Creating a consistent, safe surface stems from first knowing more about your field. What do you really know about your field?

For instance, what sort of grass grows on it? How much water or fertilizer does it need to thrive; how do different climates effect its shock absorbency? Or, overall, how safe is your field?

Don’t kid yourself. The field you play on can be just as important as the equipment your players use to protect themselves. Whether synthetic or natural grass, a consistent, safe playing surface should be your No. 1 goal. Educating yourself becomes the first step. That’s why we’ve drawn up this primer that highlights field components, some maintenance concerns and suggestions, and a test that determines the safeness of your field.

Natural Grass
Properly cultivating a natural grass field starts with the right grass or mixture of grasses. While there are thousands of football fields, according to Iowa State’s David Minner, an associate professor of horticulture and an extension turfgrass specialist, two major types of grasses – bermuda or bluegrass – cover them. These grasses, or one of their many varieties, provide high quality, dense natural sports field covers.

To determine which grass is right for your program start with where you are – geography and climate zone determine which grass grows best. Finding the right grass for your field means considering rainfall, growing season, soil types, and most importantly climate zone. Is your field located in a warm or cool season climate zone?

Stretching across the northern tier of states, cool season climate zones include much of northern California, most of Nevada, northern parts of both Arizona and New Mexico, all but the most southern parts of Kansas, all of Missouri and Tennessee, the northernmost reaches of North Carolina, plus all the states north of this list. Meanwhile, all regions south of this line of states make up the warm season climate zone.

And while unearthing the warm and cool zones may sound like a logical method of distinction, the geography-best grass type formula gets further complicated by more specific climate zones. For Mexico, Canada and the United States, there are twelve such climate zones. Bluegrass grows best in cool season zones, while bermuda – a sun loving grass – is considered the “South’s Grass.” Both require moderate levels of lawn care. To learn more about climate zones and the type of grass that best suits your geographical area, check out these two websites: (1) www.bermudagrass.com and (2) www.bluegrasses.com.

Selecting the right grass can effectively combat both warm and cold season effects on grass turf. For example, freezing affects fields in a couple of ways. First, frozen fields are hard fields. Testing has shown this to be true. Freezing temperatures also effect the ability to keep grass alive. In fact, you’ll have wasted valuable time and resources if you plant a warm season grass only to discover that the hard freeze that is normal for your winter will kill it out. The same goes for cool season grasses planted where summer temps shrivel them to nothing.

Poor drainage can cause other maintenance concerns. The majority of grass fields – particularly those at the small college or high school level – have native soil bases, meaning they were built on the soil that was readily available at the site of construction. Investing money in a sand-filled, manufactured base can dramatically improve drainage, even reduce or eliminate the need for a crown. While conventional football fields needed an 18 to 24-inch crown for drainage, sand-based grass fields and synthetic surfaces – fields that drain vertically instead of horizontally – can get by with as little as a six-inch crown.

Having the right grass and understanding the way seasonal changes can effect it are just the start – taking pro-active steps to maintain your field are just as important.

Coaches who can limit usage, control the weather and spend unlimited amounts on field maintenance will have no problem with a natural grass field. Unfortunately, most school districts don’t have deep pockets, just as most coaches can’t control the weather. However, they can work together to develop a plan that limits, or at least monitors and hopefully controls field usage. In a preliminary study, Iowa State’s Minner found the actual number of events scheduled – games, practices, and extracurricular activities such as graduations – exceeded by one-third the number of events that would render the field conditions unrecoverable and more than double the number most natural grass fields could accommodate and then fully recover. Although unofficial, Minner’s survey supports one claim – fields are over used.

Much like a cold, the best cure for an overused field is rest. Another turf expert recommends 75 to 90 days during prime growing season – something that is unlikely to happen. But by not allowing those with the knowledge to re-sod, re-sprig or re-seed, turf expert Fred Perry, who has evaluated more than 17,000 playing fields across the United States, foresees a different trend emerging. “If cultural aspects of our maintenance program do not improve, then by 2020 the majority of our soccer, football multi-purpose fields will be some form of synthetic surface.”

“Under today’s present conditions of misuse, overuse, lack of proper equipment and supplies to repair, and then time to repair, there’s absolutely very little help we can get in repairing or maintaining our athletic fields,” says Perry, who runs Ground Maintenance Services in Orlando, Florida and conducts hundreds of clinics a year for coaches.

“What I see is a very difficult equation, because everybody wants safe, playable fields, but they don’t want to maintain or use them properly.”

While Perry admits that the mechanical nature of turf maintenance makes it more difficult, he compares field maintenance to child-rearing. “If children are not given the proper food, if they’re not given the proper exercise or rest, then you’ve got stressed out, worn out youngsters,” Perry says. “It’s no different with turf, although turf does repair itself sufficiently if it is given some time and an opportunity to do so.”

To give turf the necessary rest, coaches can periodically move stressful practice drills, instead of always performing them in the same location. Unfortunately, because hash marks and goal posts remain fixed, other stressful drills simply cannot be moved. And while separate practice facilities allow coaches to displace some of a field’s workload, not every school, especially those in major cities, has that luxury.

Overuse, poor or misguided maintenance, and uncontrollable climatic conditions all lower the shock absorbency of your field. But how hard is too hard? This can be determined by finding out your field’s GMAX level – a test that uses the methods approved by the American Society of Testing and Materials. Your field lies in the best shape when it rates between 100 and 150 G, and you should consider redoing your field at 175 G or beyond. While natural grass generally falls somewhere between 70 and 100, it has ironically been rated as having both the highest and lowest GMAX levels. For example, muddy grass tips the GMAX scale between 65 and 70, while frozen natural grass rates anywhere from 175 to 275, the latter being well above the safe range.

Artificial Surface
Mention the term artificial turf and many people think of one specific surface – AstroTurf, the first artificial surface installed in the Houston Astrodome in 1966. Since that pilot project, numerous companies have produced similar types of surfaces, but none has survived as much hype or criticism nor undergone such research and development as the original synthetic turf. Since its inception more than 35 years ago, synthetic turf has been greatly improved. In fact, today’s artificial surfaces are more diverse, more durable, more grass-like and, most importantly, safer than their predecessors.

In order to understand synthetic surfaces better, you first have to understand that not all artificial turf is identical.

The synthetic surface of yesterday, conventional artificial turf provides the most durability – up to 12 years of use – and continues to evolve into a safer more reliable surface. Today’s artificial turf includes three major components: a shock absorbing subbase comprised largely of recycled rubber, an additional layer of closed cell foam unaffected by rot, mold, mildew, bacteria, freezing, thawing, water, most chemicals and foot traffic, and a more durable, knitted nylon fabric that resists matting, reduces abrasiveness, and provides more uniform traction and ball roll.

Like the aforementioned “workhorse,” newer infill type surfaces have a similar life span – firecasted to be eight to ten years. By combining a slightly longer fabric (2 1/4 to 2 1/2 inches) with infill of rubber, or a combination of both rubber and sand, synthetic surfaces became more grass-like and more affordable. The infill provides support for the lightweight fibers in the fabric.

Another type of infill product called NexTurf, engineered solely by Southwest Recreational Industries, combines two different fabrics matrixed together at two distinct heights – creating a more sophisticated artificial surface. The highly-textured, nylon root fabric adds density, improves traction and enhances drainage, while the upper level of monofilament polyethylene fibers makes the appearance and feel more grass-like than traditional infill surfaces. Minimal rubber filling with special synthetic rubber (not recycled tires) means better energy return, added shock absorbency, less compaction, less abrasion and longer life.

Finally, another version of synthetic surface allows natural grass to grow through a specially woven synthetic turf base. This hybrid version gives natural grass the luxury of having a controlled, stable base. Doing so ensures proper drainage and predetermines root growth patterns – two factors which make the surface more durable and consistent – but because it’s simply stabilized natural grass, this surface requires additional traffic management and maintenance, much like a grass field.

According to Jim Savoca, the executive vice president of sales for Southwest Recreational Industries, his company attempts to create both durable, long-lasting and safe synthetic surfaces.

“For football, our goal is to design a field with a life-span of eight to ten years – one that can sit outside unprotected. We’re talking about 100 degree temperature swings, snow, rain, sleet, sunlight, and virtually unlimited use – probably 300 days a year where people are on it, everything from gym classes, football, soccer and graduations – (as a result) the field is only going to get firmer. But the number one criteria for Southwest Recreational Industries has always been to protect the athlete.”

From the ground up, synthetic surfaces include several components – base, pads, infills, and fiber construction or fabric. First, manufacturers start with a crushed stone base built for drainage that reduces the need for a crown. On top of the base layer goes a pad for additional shock absorbency. Several types of pads exist, giving synthetic shoppers a chance to find one that meets budget constraints and life expectancy. Pads provide consistent and continuous shock absorbency on fields with infill where the level of compaction changes over time. A third component of the newer, more affordable synthetic surfaces is the infill – usually sand (heavier) or rubber (more resilient), or some patented combination of the two. Finally, different fibers (i.e. nylon, polypropylene and polyethylene) construction methods, fabric densities and lengths create different levels of traction, abrasion, look and feel.

Unlike a natural grass field, the majority of cost for synthetic surfaces – perhaps as much as 95 percent – comes initially. Once installed, the maintenance costs are minimal. Moreover, when one considers the actual number of events the field can host, the cost per user or event drops dramatically. According to SWRI’s Savoca, approximately 40 percent of the initial cost of a synthetic surface goes into constructing the base, which once in place becomes reusable for up to forty years.

When compared to natural grass fields, artificial turf maintenance involves less cost, less know-how, and fewer headaches. While the base ensures proper drainage, lines that have been inset as part of the fabric – if you’ve chosen this option – make repainting them obsolete. Otherwise, lines may need to be repainted annually. The only other maintenance involves cleaning or sweeping the turf when needed and removing stains as they occur.

If your team plays on a natural grass field, you might assume that your athletes are safer than those who play on artificial surfaces. That my not always be true. For comparison purposes, frozen synthetic surfaces rate between 75 to 150, and showed similar GMAX ranges (75 to 125) as natural grass fields under normal football conditions – both proof that field safety depends on more than playing surface. Maintenance, geography, overuse and misuse, and climatic conditions all play a role.

Make The Right Choice
As Southwest Recreational Industries’ Savoca suggests, choosing a field – natural or synthetic – depends on the situation.

“At the high school or small college level, (coaches and administrators) only have one chance to do this right. No matter what field they choose, they’re probably going to have to live with it for a long time. You’re making a big investment and the investment when you buy synthetic is a uniform, predictable place to play for eight to twelve years.

That’s the difference – when you’ve got a natural grass field you’ve got a changing entity – it’s one thing in August, and that grass field is a whole different thing in November. No matter what you do you’ve got to limit use.”

That’s why he encourages coaches to “talk to people like them.” Coaches and administrators who have been through the process can point them to organizations, websites, or other resources that they may have used. By talking to those who have been in similar situations, coaches can make an educated decision – whether they are considering a synthetic or natural surface.

This education may play the decisive role in assuring a safe playing surface. Whether choosing natural grass or an artificial surface, coaches must do their homework, and then take an active role once the surface is in place to keep it safe.

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