SynopsisAthletic field groundskeepers are being pressured to mow turf too low
by coaches who believe that their athletes can run faster on shorter
cut grass. This practice leads to scalped fields and damaged turf. A new study supports the author's contention that lower cutting heights
do not increase athlete performance. The author proposes that
mowing cool-season high school football fields at 2 inches should be
a standard, justifiable procedure. Background discussion The athletic field is an unusual turfgrass situation. It is subjected
to tremendous demands, undreamed of in a residential lawn setting. As
explained by Goss and Cook (1993), the field must be able to “withstand
intensive traffic under a range of climatic conditions.” To support
this activity, the field must first be designed and constructed properly
(Indyk, 1986). Realistic scheduling of the use of the field is also
critical since an irresponsible overuse of living turfgrass will cause
it to fail (Goss & Cook, 1993). TABLE 1. Forty-yard spring times of seven JV
football players.
Lane sprint order: 3-2-1-1-2-3. | Runner | 3" Lane | 2" Lane | 1" Lane | One | 6.13 | 6.13 | 6.02 | 6.08 | 6.08 | 6.11 | Two | 5.62 | 5.84 | 5.93 | 6.05 | 5.96 | 5.92 | Three | 5.42 | 5.41 | 5.47 | 5.74 | 5.68 | 5.45 | Four | 5.99 | 6.02 | 6.03 | 6.35 | 6.39 | 6.20 | Five | 6.28 | 6.46 | 6.57 | 6.65 | 6.72 | 6.47 | Six | 5.98 | 6.10 | 6.18 | 6.13 | 5.98 | 6.19 | Seven | 5.98 | 5.98 | 5.99 | 6.15 | 6.06 | 6.14 |
| Average | 6.04 | 6.06 | 6.04 |
Equal in importance to initial development and subsequent scheduling
of use is the implementation of sound maintenance programs. A poorly
maintained field will be less able to sustain and recuperate from the
wear and tear of sports activities. To endure these pressures turfgrass
must be vigorous, dense, and deeply rooted. Proper mowing practices play an integral role in realizing these objectives.
Cockerham (1989) noted this relationship: The first and most apparent
result of mowing on grass is that some of the photosynthetically active
tissue is removed, reducing the plant food production capability. A direct result of that removal is a reduction in root growth. Indeed,
the relationship between mowing and root development was established
early on in pioneering turfgrass research. TABLE 2. Forty-yard spring times of seven
varsity football players.
Lane sprint order: 3-2-1-3-2-1. | Runner | 3" Lane | 2" Lane | 1" Lane | One | 5.43 | 5.25 | 5.35 | 5.36 | 5.14 | 5.39 | Two | 5.25 | 5.28 | 5.27 | 5.35 | 5.27 | 5.21 | Three | 5.46 | 5.40 | 5.24 | 5.24 | 5.20 | 5.41 | Four | 5.71 | 5.65 | 5.63 | 5.57 | 5.41 | 5.56 | Five | 5.13 | 5.31 | 5.27 | 5.14 | 5.28 | 5.05 | Six | 5.57 | 5.43 | 5.44 | 5.42 | 5.44 | 5.40 | Seven | 5.76 | 5.63 | 5.75 | 5.77 | 5.71 | 5.88 |
| Average | 5.46 | 5.39 | 5.42 |
A 1961 experiment by Deal clearly showed the influence of higher mowing
on Poa pratensis (Kentucky bluegrass) root quantity. The study compared
two-inch and one-inch clipping heights and the resulting increase in
rootmass associated with the higher cut. That investigation, and others like it, contributed to the basic understandings
contained in modern textbooks that instruct today’s turfgrass students.
As explained by Hull (1996), a closely mowed turf will have a less developed
root system and will be less wear tolerant. For the cool-season species
used for sports turf, a cutting height above two inches will produce
more rootmass than a height below two inches. This root/shoot relationship becomes a critical factor on football
fields where stress is the norm, and each management decision requires
a careful consideration of consequences. Nowhere is the attention to
this detail more important than in the maintenance of school athletic
facilities. A poorly developed root system will be less able to access
the water and nutrients needed for sustenance. This will require additional
expenditures for the materials and labor needed to intensify fertilization
and irrigation programs. Clearly then, on facilities with limited resources, mistakes made in
basic procedures are magnified, becoming not only wasteful but also
difficult to rectify and potentially devastating. Despite its merits, the proposal to raise football field mowing heights
is met with resistance from coaches and players. Joe Casarella, the
athletic director of the North Rockland Central School District, believes
that most coaches are convinced lower heights of cut will enhance the
athletes running performance. He also feels that these coaches are unaware
that low mowing practices can negatively affect the playing field. In an actual survey of football coaches “the overwhelming attitude
of the coaches was that a higher cut turf would somehow impede the speed
of the athletes (especially fast running backs) and thus somehow affect
the outcome of the contest” (Caton, 1993). This belief persists despite the lack of data to support it. In their
athletic field cooperative extension publication, Goss and Cook (1993)
wrote, “shorter mowing will provide a denser turf and a faster
playing surface. Higher mowing will provide a slower surface but increased
rooting depth.” It is unclear if the authors are referring to running
speed or perhaps to ball roll. Canaway and Baker (1993) linked ball
roll and mowing height. TABLE 3. Forty-yard spring times of six high
school cross country runners.
Lane sprint order: 1-2-3-3-2-1.
Unlike the football players, these athletes ran in spikeless racing
shoes. | Runner | 3" Lane | 2" Lane | 1" Lane | One | 5.33 | 5.33 | 5.26 | 5.40 | 5.36 | 5.16 | Two | 5.50 | 5.25 | 5.35 | 5.44 | 5.45 | 5.41 | Three | 5.65 | 5.52 | 5.38 | 5.65 | 5.85 | 5.68 | Four | 5.79 | 5.60 | 5.67 | 5.50 | 5.34 | 5.26 | Five | 4.97 | 4.96 | 4.90 | 4.85 | 4.85 | 4.86 | Six | 5.06 | 5.07 | 5.10 | 5.23 | 5.38 | 5.26 |
| Average | 5.36 | 5.33 | 5.26 |
It is accepted in the golf world that low cut heights are vital to
playability, and superintendents manage turf for low heights. At a different
(mowing) level, that holds true in other sports like soccer. Cockerham,
Weston, and Kiesling (1995) constructed an apparatus for ball roll measurement
in preparation for World Cup Soccer USA. Their device showed an increase
in ball roll distance with a decrease in mowing height. However, there
is nothing in the literature which links mowing height and foot speed. IPM and Mowing HeightIn pest management, as in playability
and field safety issues, higher mowing means better
fields. |
Before the 1970s, the general public gave little thought
to the potential health and environmental risks associated
with chemical pesticides. Today, however, these concerns
are growing, especially where children are involved. In light of these concerns, lawn care programs that rely
heavily on these chemicals are being questioned. An official report from the New York State Attorney General’s
Office urged schools to adopt those policies and practices
which would enable them to reduce or eliminate pesticide
use (Volberg, Surgan, Jaffe, & Hamer, 1993). In 1996,
the New York State Education Department adopted the policy
that all New York schools must adopt integrated pest management
(IPM) policies and practices. In considering the issue of pesticide use in the school
environment, the U.S. Environmental Protection Agency (EPA)
has stated that “it is in everyone’s best interest
to reduce exposure to potentially harmful chemicals.” Both the EPA and the State Attorney General advocate the
adoption of IPM as an alternative to scheduled applications
of pesticides. The EPA defines IPM this way: “IPM is an effective
and environmentally sensitive approach to pest management
that relies on a combination of common-sense practices….
IPM programs take advantage of all pest management options
possibly including, but not limited to, the judicious use
of pesticides.” For the athletic field manager, this means reducing pest
populations below levels that would compromise field quality
by using all available methods, especially those tools that
promote vigorous and competitive turfgrass. As observed by Emmons (1984), “growing healthy grass
is the foundation of an IPM program” (p. 225). Obviously,
mowing at recommended heights becomes an important component
of IPM strategies. A vital, well-rooted turf will better tolerate the attack
of insect pests. Plant health will also contribute to quicker
recovery from the injury caused by these insects (Baxendale
& Grant, 1995; Emmons, 1984; Hull, 1996; Vittum, 1995). Resistance to diseases is also increased with higher mowing
(Smiley, Dernoeden, & Clarke, 1992). Dernoeden and Jackson
(1978) studied the effect of mowing height on leaf spot
disease of Kentucky bluegrass. The impact of low mowing
on brown patch severity of Lolium perenne (perennial ryegrass)
was reported in field studies by Fidanza and Dernoeden (1993).
After extensive research on summer patch, Clarke (1994)
supports sensible mowing heights as a disease management
tool. In addition to these three diseases, the Compendium of
Turfgrass Diseases lists powdery mildew, rusts, Fusarium,
and Pythium as being reduced in severity by higher mowing
(Smiley et al., 1992). The relationship between low mowing and weed invasion
is well researched. An early experiment demonstrated that
besides developing more rootmass, a higher cut Kentucky
bluegrass turf had fewer weeds. A test plot mowed at 1.5
inches averaged 6.8 crabgrass plants and 10.1 broadleaf
species per 32 square feet. Mowed at 2.5 inches, the weed
populations dropped to .5 crabgrass and 1.9 broadleaf (Deal,
1967). Results of a three-year field study by Dernoeden, Carroll,
and Krouse (1993) indicated that the best cultural management
strategy for suppressing crabgrass encroachment in Festuca
arundinacea (tall fescue) is raising the height of cut.
Adams (1980) reported an increase in Poa annua (annual bluegrass)
cover as the mowing height of perennial ryegrass was reduced.
Neal (1994) listed the reasons why well-maintained turf
has a competitive advantage over weeds: Dense turfgrass can successfully compete for limited nutrients
and water Mature, healthy turfgrass plants have an advantage over
newly emerging or immature weed species Some weed species grow better in conditions that do not
favor turfgrass species Higher leaf densities of healthy turf produce lower soil
temperatures which discourage weed species that germinate
at high soil temperatures Obviously, the control of turfgrass pests involves all
facets of management with an emphasis on proper cultural
operations.
If the athletic field manager wishes to minimize the role
of pesticides in his programs, he must become more expert
in turfgrass care.
In pest management, as in playability and field safety
issues, higher mowing means better fields.
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The purpose of this study is to investigate the influence of clipping
height on player speed and turfgrass quality on high school football
fields. In reviewing the literature, two key issues emerge which argue for
the enhanced vigor associated with higher mowing on tight-budgeted school
football fields. In light of the fact that there is no evidence that
lower mowing increases foot speed, these fields should be mowed at two
inches to promote safer fields of better playing quality and produce
more pest-resistant turfgrass stands. Harper, Morehouse, Waddington, & Buckley (1984) determined that
a relationship exists between maintenance factors, surface and vegetative
characteristics and field-related injuries in high school football.
A follow up study demonstrated that greater shear resistance [traction]
and lower impact values [more resilient field surface] were related
to maintenance practices (Rogers, Waddington, & Harper, 1988). While
traction and hardness will influence the sport participant’s perception
of playing quality (Canaway & Baker, 1993), their greater importance
clearly lies in field safety. Those practices, like proper mowing that
contributes to improved turf cover, must be encouraged. Sifers and Beard
(1996) acknowledged that “many impact-type injuries are related
to varying degrees of surface hardness.” They also demonstrated
that surface hardness is decreased with increasing heights of cut. With limited budgets, the margin for error narrows, making it all
the more important to adhere to sound mowing practices. A 1994 industry
profile survey conducted by the Sports Turf Managers Association reported
that the average cost per acre for the maintenance of professional sports
facilities was $4,333. The figure for school fields was $658 per acre.
Player safety, as well as enjoyment, needs to be considered in the efficient,
effective and responsible management of school facilities. An unpublished study by Gramckow (1966) showed no correlation between
height of cut and foot speed. Conducted at Cal-Turf Nurseries in Camarillo,
Calif., the study investigated characteristics of turfed areas such
as impact energy absorption, shear strength, and wear tolerance in addition
to the clipping height/running speed relationship. Running tests were
performed on 100-yard tracks with eight tracks laid out on Bermudagrass,
six on fescue and six on bluegrass for a total of 20 separate lanes.
These lanes were cut at heights ranging from 1 inch to 3 inches in half-inch
increments, with two additional lanes on the Bermuda grass at one-half
inch each. Ten high school football players were timed in a 100 yard sprint,
running once on each track. Randomly selected, the track order was different
for each runner. The 10 running times for each track were then averaged.
The results showed no significant difference in sprint times. The conclusion
was that cutting height had no appreciable affect on running speed.
Considering the location and time elapsed since the California study,
it is apparent that further research is needed to verify the important
inference that mowing below two inches does not enhance athletic performance.
New York study The subjects for this study were male students from a more than 2,000
student high school serving more than 7,000 student suburban school
district with a strong “tradition of excellence” in athletics.
The 20-student sample in this study was selected from pre-existing,
self-contained interscholastic sports teams for which the young players
had successfully tried out. These teams were junior varsity and varsity
football and cross country. Athletes ranged in age from 13 to 18 and were selected by their respective
coaches as being representative of a range of athletic abilities and
running speed potential. The subjects were not told any details of the
experiment. They were told only that their running speed would be tested
and recorded in a series of 40-yard sprints, and they were encouraged
to perform to the best of their abilities. Players were separated into groups based on their respective teams.
The subjects included seven from junior varsity football, seven from
varsity and six from cross-country. All athletes wore cleated sports
shoes except the cross country runners who wore a smooth-soled spikeless
racing shoe. The study was conducted at a time that corresponded to the athletes’
midseason so that they would possess their optimum physical conditioning
and thereby minimize a fatigue factor that might influence sprint order
results. Results discussion To test the hypothesis that there would be no difference in running
speed on turfgrass mowed at the three different heights, the recorded
sprint times were evaluated first to determine means and probability
of the means being statistically significant. The stability of individual sprint times is consistent with the hypothesis.
There was no statistically significant difference in the comparison.
When the sub-sample of only the 14 football players is examined, the
data are equally supportive. The average time (rounded to the nearest
tenth) for the 40-yard sprint of fourteen high school football players
was 5.7 seconds at each clipping height. Tables 1 and 2 (above) show the recorded times of these 14 athletes
and clearly show their nearly identical performances in running the
40 yards regardless of mowing height. When the data were examined in this sub-group manner, the cross country
results seemed at first glance to indicate an association between height
of cut and foot speed. Table 3 (above) shows what appeared to be a gradual improvement in
running times as the height was lowered with lane averages of 5.36 seconds
at 3 inches, 5.33 at 2 inches and 5.26 at 1 inch. The significance of these means was tested. The statistical technique
reveals that the one-tenth of a second difference in times is easily
within the realm of chance and is of no significance. What may be worth noting, however, is the fact that 67 percent of
the spikeless racing shoe cross country runners clocked their best time
on the one-inch turf. Considering the fact that only a third of the
cleated subjects recorded their best times at this height, as might
be expected in a three-lane experiment design, the possible influence
of shoe type and traction suggests further study. Indeed, it is possible
that shoe type may have played a role in the origin of the belief in
a clipping height/foot speed correlation. Conclusion This study was conducted to determine if lower cutting heights on
high school football fields might be justified by a corresponding enhancement
of athletic performance. No such relationship was observed. Cool season turfgrasses, like Kentucky bluegrass, grow most of their
roots in spring and fall. It is during these times, which coincide with
the outdoor school sports season, that cutting height will have its
greatest influence on root growth. The results of this study argue for sensible mowing practices that
provide safer athletic fields, promote better playing quality and produce
a healthier, pest-resistant turf requiring fewer inputs. For these reasons,
mowing cool-season high school football fields at 2 inches should be
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