8 SportsTurf | July 2014 www.sportsturfonline.com
Field Science | By Tom Serensits and Dr. Andy McNitt
A
s another football season looms on
the horizon, coaches are finalizing game
plans they hope will bring them season-
long success on the field. Sports turf
managers are no different but instead
of wins, success means providing playing field conditions
that maximize both playability and safety.
The current heightened focus on athlete safety has
increased the scrutiny of all potential contributors to ath-
lete injury, including the playing surface. In fact, all NFL
fields are now tested and certified before every game using
a set of "recommended practices." These recommended
practices include tests such as field hardness (Gmax), soil
moisture, infill depth, and visual inspections, depending
on the surface type.
Much of the increased concern for athlete safety is
due to a heightened awareness of the issues surrounding
concussions. Research indicates that most concussions are
the result of violent athlete to athlete collisions. However,
this same research indicates that approximately 10-15%
of concussions in American football are caused by the
head hitting the surface. Consequently, the hardness of
the playing surface can affect injury risk.
By routinely monitoring field hardness levels, manage-
ment practices can be implemented well before the surface
exceeds hardness thresholds. For example, surface hardness
of NFL fields is tested with the Clegg Impact Tester. The
We have measured Gmax values
well over 250 Gmax (Clegg) on dry,
compacted fields. As a reminder, the
NFL threshold is 100 Gmax.
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UpdaTe on Field
SaFeTy TeSTing
Penn State's Pennfoot
machine measures both
rotational and linear (trans-
lational) traction. Rotational
traction is more related to
injury risk while linear is
more related to performance.
For rotational traction,
Pennfoot measures the
amount of force required to
rotate the shoe in the turf.
