CERTIFIED ATHLETIC TRAINERS PERCEPTIONS OF LOWER LIMB
INJURIES THAT OCCUR ON ARTIFICIAL TURF VERSUS NATURAL GRASS

A THESIS
Submitted to the Faculty of the School of Graduate Studies
and Research
of
California University of Pennsylvania in partial
fulfillment of the requirements for the degree of
Master of Science

by
Ryan Joseph Diedrich Wildenhain

Research Advisor, Dr. Thomas F. West
California, Pennsylvania
2011

ii

iii
ACKNOWLEDGEMENTS
I would like to take this opportunity to identify and
thank the individuals that have played a role in my life
and in the completion of this thesis. First, I would like
to recognize the ones that mean the most to me, my family
and friends. To my family, thank you for helping me become
the individual I am today, I love you all. Without their
guidance, I would not have strived to be the first in our
family to earn a Master’s degree. To my friends back in
Illinois, I can always count on you all when I need you the
most. A special tribute goes to Jon and Jeremy Scholnick.
Although they are no longer here, they motivate me to live
life to the fullest on a daily basis. A very special thanks
must be rewarded to the individual that has become my best
friend during my time at California University of
Pennsylvania, Colleen Frickie. Without her I would not have
enjoyed Western Pennsylvania as much as I did.
Next, I would like to thank the individuals at
Brownsville Area High School. I will never forget my first
position as a Certified Athletic Trainer. The experiences I
encountered at B-Ville will echo throughout my Athletic
Training career.
Now I would like to recognize my thesis committee.
Words cannot describe how grateful I am that Dr. Tom West
was my research advisor. I have learned more about the
research process from Tom than I even thought was possible.
Additionally, without Tom’s guidance I would not have
chosen Dr. Laura Miller and Mr. Jeff Hatton to be a part of
my thesis committee. The knowledge, input, and support
provided by Tom, Laura, and Jeff made completion of this
thesis extremely easy. Thank you for all your help.

iv

TABLE OF CONTENTS

Page
SIGNATURE PAGE

. . . . . . . . . . . . . . . . ii

AKNOWLEDGEMENTS . . . . . . . . . . . . . . . . iii
TABLE OF CONTENTS
LIST OF TABLES
INTRODUCTION
METHODS

. . . . . . . . . . . . . . . iv

. . . . . . . . . . . . . . . . vii

. . . . . . . . . . . . . . . . . 1

. . . . . . . . . . . . . . . . . . . 7

Research Design. . . . . . . . . . . . . . . . 7
Participants . . . . . . . . . . . . . . . . . 8
Preliminary Research

. . . . . . . . . . . . . 9

Instrument

. . . . . . . . . . . . . . . . . 10

Procedures

. . . . . . . . . . . . . . . . . 10

Hypotheses

. . . . . . . . . . . . . . . . . 11

Data Analysis
RESULTS

. . . . . . . . . . . . . . . . 12

. . . . . . . . . . . . . . . . . . . 14

Demographic Information
Hypothesis Testing

. . . . . . . . . . . . 14

. . . . . . . . . . . . . . 18

Additional Findings . . . . . . . . . . . . . . 22
DISCUSSION . . . . . . . . . . . . . . . . . . 30
Discussion of Results . . . . . . . . . . . . . 30
Conclusions . . . . . . . . . . . . . . . . . 35

v
Recommendations

. . . . . . . . . . . . . . . 36

REFERENCES . . . . . . . . . . . . . . . . . . 37
APPENDICES . . . . . . . . . . . . . . . . . . 39
APPENDIX A: Review of Literature

. . . . . . . . . 40

Introduction . . . . . . . . . . . . . . . . . 41
Bony and Ligamentous Anatomy. . . . . . . . . . . 42
Ankle

. . . . . . . . . . . . . . . . . . 42

Knee . . . . . . . . . . . . . . . . . . . 43
Risk Factors . . . . . . . . . . . . . . . . 45
Shoe-Surface Traction. . . . . . . . . . . . 45
Predisposing Factors

. . . . . . . . . . . 47

Previous Artificial Turf Versus Natural Grass
Studies

. . . . . . . . . . . . . . . . . . 49

Injuries . . . . . . . . . . . . . . . . . 50
Shoe-Surface Loading

. . . . . . . . . . . 53

Artificial Turf Comparison . . . . . . . . . 55
Preventive Measures . . . . . . . . . . . . . 56
Summary . . . . . . . . . . . . . . . . . . . 58
APPENDIX B: The Problem . . . . . . . . . . . . . 60
Statement of the Problem . . . . . . . . . . . 61
Definition of Terms . . . . . . . . . . . . . . 62
Basic Assumptions . . . . . . . . . . . . . . . 62
Limitations of the Study . . . . . . . . . . . . 63

vi
Delimitations of the Study . . . . . . . . . . . 63
Significance of the Study. . . . . . . . . . . . 64
APPENDIX C: Additional Methods . . . . . . . . . . 65
IRB: California University of Pennsylvania (C1) . . . 66
Artificial Turf Versus Natural Grass Survey (C2)

. . 78

Cover Letter (C3) . . . . . . . . . . . . . . . 90
Pilot Study Results (C4) . . . . . . . . . . . . 92
REFERENCES . . . . . . . . . . . . . . . . . . 94
ABSTRACT . . . . . . . . . . . . . . . . . . . 97

vii

LIST OF TABLES

Table

Title

Page

1

Frequency Table for Gender . . . . . . . 15

2
3

Frequency Table for Years Certified
. . . 16
Frequency Table for Collegiate Governing
Body Affiliation . . . . . . . . . . . 16

4

Frequency Table for Primary Sport
Affiliation . . . . . . . . . . . . . 16

5

Frequency Table for NATA District
Affiliation . . . . . . . . . . . . . 17

6

Perceived Risk Scores by Injury Location

7

Mean Injury Risk by Collegiate Governing
Body
. . . . . . . . . . . . . . . 20

8

Independent Sample T-Test Comparing the
Mean Risk Scores Between Male and Female
Certified Athletic Trainers’ . . . . . . 21

9

Mean Risk Scores by Years Certified

10

Mean Risk Scores by Primary Sport

11

Mean Risk Scores by NATA Districts . . . . 24

12

Frequency Table for Certified Athletic
Trainers’ Perception of Different Field
Types and Their Role in Different Injury
Categories
. . . . . . . . . . . . . 27

13

Frequency Table of Certified Athletic
Trainers’ Perceptions of Which Field
Surface is Safer for Athletes to Practice
and Compete on During Inclement Weather . . 27

. 19

. . . 22
. . . . 23

viii
14

Frequency Table for Certified Athletic
Trainers’ Overall Perception of Which Field
Surface is Safer . . . . . . . . . . . 27

15

Frequency Table for Certified Athletic
Trainers’ Field Surface Utilization During
Practice and Games . . . . . . . . . . 28

16

Frequency Table for Certified Athletic
Trainers’ Perceived Condition of Their
Field Surface . . . . . . . . . . . . 28

17

Frequency Table for Preventive Measures
Taken by Certified Athletic Trainers’ While
Supervising Their Primary Sport . . . . . 28

18

Frequency Table for Certified Athletic
Trainers’ Perceptions on Which Field
Surface They Associate Specific Lower Limb
Injuries With . . . . . . . . . . . . 29

1

INTRODUCTION

As each year passes, artificial turf is becoming the
preferred field surface for outdoor athletics. Artificial
turf can be seen at all levels of athletic competition.
Many of us were taught early in our career that sport
participation on artificial turf is more dangerous. As the
artificial turf industry has advanced their products to
become more like natural grass, the athletic shoe industry
has modified their products as well to accommodate
alternative field surfaces in order to help reduce the
overall amount of injuries.
Artificial turf surfaces have been used for many
years, dating back to the 1960’s. Even though artificial
turf has been around for many years; there is still
speculation whether or not artificial turf increases the
risk for injuries. Within the past decade many institutions
have converted from natural grass to artificial turf to
reduce maintenance costs, improve athletic performance, and
appeal to recruits. As more institutions utilize artificial
turf, we will begin to observe injury trends that may be

2
contributed to field surface or shoe selection, which will
warrant further research.
The research that currently exists does not
conclusively indicate if artificial outdoor athletic field
surfaces are safer for athletic participation over the
traditional natural grass fields. Many studies have
examined the relationship between field surfaces and
occurrence of injuries.1-9 Meyers et al1 compared the injury
incidence rate of high school football games on FieldTurf,
a new generation of artificial turf in filled with rubber
particles compared to natural grass. The outcome of the
research showed an injury incidence rate of 15.2 per ten
games on FieldTurf versus 13.9 per ten games on natural
grass. FieldTurf may have exhibited a higher incidence of
injuries, but not high enough to say that it poses a
statistically significant increase in risk. In addition,
each field surface displayed distinctive injury patterns
that merited further research.

When Meyers2 conducted

further research, he used 24 Division I collegiate football
teams to compare the incidence of injury on FieldTurf
versus natural grass during games. From the 2253 total
injuries documented, 1050 (46.6%) occurred on FieldTurf,
and 1203 (53.4%) on natural grass. The research was funded
by FieldTurf and a multivariate analysis per 10 team games

3
displayed significantly lower injury incidence rates on
FieldTurf compared to artificial turf.
Football is not the only sport that is utilizing
artificial turf. Many other sports such as soccer, field
hockey, lacrosse, rugby, and even some baseball and
softball fields now make use of artificial turf. To better
understand how artificial turf affects soccer, Steffen et
al3 conducted a study that utilized 2,020 young female
soccer athletes. The results of the study showed a higher
incidence of ankle sprains on artificial turf compared to
natural grass even though more games and overall injuries
were documented on natural grass. Ekstran et al4 found
similar results while examining European club soccer
players that competed and trained on artificial turf versus
a control group of Swedish Premier League players. The
higher rate of ankle sprains could be contributed to the
sports increased demand for rapidly changing direction and
a high rotational torque. More research is necessary to
determine what type of affect artificial turf has on lower
limb injuries for outdoor sports other than soccer and
football.
In an effort to reduce injuries that do occur on
artificial turf, several studies have been completed to
highlight potential risk factors to include improper

4
footwear that leads to too little or too much shoetraction.5,

10-12

When Villiwock et al5 performed a study that

examined several different types of cleated shoes on four
different field surfaces; the turf style cleat exhibited
the least amount of rotational torque. High rotational
torque values can contribute to lower limb injuries,
whereas low rotational torque values may negatively affect
athletic performance and contribute to injuries as well.
Higher torque values will occur when an athlete wears
improper footwear for a specific surface or cleats that are
too long. Lower rotational torque values will take place
when there is improper footwear selection and during
inclement weather. Not only can the selection of proper
footwear improve an athlete’s performance, but it can
reduce the incidence of a potential lower limb injury.
Other predisposing factors that contribute to the
incidence of lower limb injuries that have been highlighted
include an athlete’s amount of playing experience, lack of
ankle dorsiflexion, and/or injury history to name a few.
Playing experience plays a role in the incidence of injury
because an individual may not obtain the conditioning and
proprioception necessary for their specific sport.

In

addition, some teams may practice on natural grass, but
compete on artificial turf.

5
A lack of participation on artificial turf could alter
the way an athlete competes, which will make them
susceptible to potential injuries.

A lack of ankle

dorsiflexion was highlighted by Noronha et al13 as being one
of the biggest risk factors in predicting ankle sprains. A
lack of dorsiflexion can potentially place an athlete’s
ankle in an open position, leaving it more unstable and
vulnerable to ankle injuries such as sprains. As with most
previous injuries, an athlete is more susceptible to
reinjury. Knowledge of previous injuries affords a
Certified Athletic Trainer the opportunity to take
preventive measures such as muscle strengthening and joint
bracing.
The primary purpose of this study is to examine
Certified Athletic Trainers perceptions of lower limb
injuries that occur on natural grass versus artificial
turf. This study will attempt to answer the following
questions: 1) Do Certified Athletic Trainers’ perceive
artificial turf to play a significant role in contributing
to lower limb injuries when compared to natural grass? 2)
Do Certified Athletic Trainers’ of different collegiate
governing bodies perceive artificial turf differently? 3)
Do Certified Athletic Trainers’ of different genders
perceive the risks of artificial turf differently? 4) Do

6
the number of years an Athletic Trainer has been certified
alter their perception about artificial turf?

7

METHODS

The purpose of this study was to examine the
perceptions athletic trainers have about lower limb
injuries that occur on natural grass versus artificial
turf. This section will include the following subsections:
Research Design, Subjects, Preliminary Research,
Instruments, Procedures, Hypotheses, and Data Analysis.

Research Design

The research design for this study was descriptive as
it provides a summary of Certified Athletic Trainers’
opinions in regards to the relationship between field
surfaces and injuries. The dependent variable was the
perceived relationship of lower limb injuries that occur on
natural grass versus artificial turf by Certified Athletic
Trainers. The independent variables included an Athletic
Trainers’ gender, years certified, collegiate governing
body affiliation, and playing surface. The strength of this
study was that there have not been any previous studies
examining the perception of athletic trainers about the
role natural grass and artificial turf play in lower limb

8
injuries. Limitations for this study included the email
addresses supplied by the National Athletic Trainers’
Association (NATA) may not be valid, the participants may
not work with an outdoor sport, and the participants may no
longer work in a collegiate setting. Another limitation was
the possibility that Certified Athletic Trainers may not
know the exact type of playing surface they have at their
institutions.

Participants

The participants for this study were 1000 randomly
selected Certified Athletic Trainers’ identified to be
working in the collegiate setting by the National Athletic
Trainers’ Association (NATA). The random sample included
Certified Athletic Trainers’ from all 10 NATA Districts.
All the participants in this study were currently employed
as a Certified Athletic Trainer with at least one of the
following outdoor sports; male or female soccer, male or
female lacrosse, male or female field hockey, and/ or
football.

9

Preliminary Research

The survey was created by the primary researcher in
consultation with thesis committee members. After review by
the committee, a panel of experts including 3 Certified
Athletic Trainers’ reviewed the survey and provided
feedback in regards to grammar, clarity of the questions
and validity.
Following Institutional Review Board (IRB) approval, a
pilot study was conducted to confirm the reliability of the
survey. The survey was administered to 20 Certified
Athletic Trainers who are currently working with the fore
mentioned collegiate sports. After one week these Certified
Athletic Trainers’ were surveyed a second time and
reliability coefficients were calculated for each question.
Of the 20 Certified Athletic Trainers selected, 11
completed the survey both times and their data was used in
the reliability analysis. A Pearson Product Moment
Correlation was used on all researcher created questions
(Appendix C4). A majority of the questions displayed
relativity scores of .30 or greater, indicating a moderate
to strong correlation. Questions that did not display a
strong reliability scores were retained because it was

10
determined that they would not affect the outcome of the
hypotheses testing.

Instruments

A survey titled Artificial Turf Versus Natural Grass
Perceptions (Appendix C2) was constructed by the researcher
and distributed using Survey Monkey. The survey consisted
of three primary sections. The first section contained two
elimination questions to determine if the participant was
qualified to complete the survey. The second section was
comprised of five demographics questions which included:
gender, collegiate governing body association, NATA
District affiliation, primary sport affiliation, and years
certified. The third and final section included thirteen
perception questions that dealt with lower limb injuries,
field surface utilization, inclement weather, and field
surface risk assessment.

Procedures

The researcher applied and obtained approval from the
IRB at California University of Pennsylvania (Appendix C1)
before any research was conducted. The study was

11
distributed through an email to 1000 randomly selected
Certified Athletic Trainers’ chosen by the National
Athletic Trainers’ Association (NATA). To obtain email
addresses the researcher contacted the NATA and requested
the maximum amount of random email addresses for
individuals currently working as a collegiate athletic
trainer from all NATA Districts. Informed consent was not
required for this survey because completion of the survey
implied consent. In addition, accompanying the survey was a
cover letter (Appendix C3) that explained the purpose of
the study. A follow-up email was sent after the first week
encouraging participants to complete the survey.

At the

end of the second week statistical data analysis began.

Hypotheses

The following hypotheses were based on previous
research and the researcher’s intuition based on a review
of the literature:
1. Certified Athletic Trainers’ will identify artificial
turf to play a significant role in causing lower limb
injuries when compared to natural grass.
2. There will be no difference in Certified Athletic
Trainers’ perceived risk of lower limb injuries that

12
occur on artificial turf versus natural grass in
different collegiate governing bodies.
3. There will be no difference in Certified Athletic
Trainers’ perceived risk of lower limb injuries that
occur on artificial turf versus natural grass by
different genders.
4. There will be no difference in Certified Athletic
Trainers’ perceived risk of lower limb injuries that
occur on artificial turf versus natural grass based on
years certified.

Data Analysis

All data was analyzed by PASW version 18.0 for windows
at an alpha level of 0.05.
1) To test the first hypothesis, an overall perceived
mean risk score for lower limb injuries that occur
on artificial turf when compared to natural grass
will be calculated. Next, the researcher compared
the perceived mean risk score to the following risk
scale to determine the significance for the first
hypothesis: -2= Significantly Lower Risk, -1=
Moderately Lower Risk, 0= Same Amount of Risk,

13
1=Moderately Higher Risk, 2=Significantly Higher
Risk.
2) A one-way ANOVA was used to determine if differences
existed between Certified Athletic Trainers’ from
different collegiate governing bodies when
perceiving lower limb injuries that occur on natural
grass versus artificial turf differently.
3) A t-test was used to discover if difference exist
between genders of Certified Athletic Trainers’ and
their perceptions of lower limb injuries that occur
on natural grass versus artificial turf differently.
4) A one-way ANOVA was used to determine if differences
exist between the number of years an Athletic
Trainer has been certified and their perceptions
regarding lower limb injuries that occur on natural
grass versus artificial turf differently.

14

RESULTS

The purpose of this study was to examine Certified
Athletic Trainers’ perceptions about lower limb injuries
that occur on natural grass versus artificial turf.

The

perceptions of Certified Athletic Trainers’ were obtained
using a survey created by the researcher. The following
section contains the following subsections: demographic
information, hypothesis testing, and additional findings.

Demographic Information

A sample of 1000 Certified Athletic Trainers’ were
randomly selected by the NATA and asked to participate in
the survey. Of the 1000 asked to participate in the survey
237 responded and 163 fully completed the survey and were
used for data analysis. The participants that fully
completed the survey included 100 males and 63 females
(Table 1). The survey included participants from all three
NCAA Divisions and both NAIA Divisions (Table 3). In
addition, individuals that answered “Other” in regards to
their collegiate division association acknowledged being

15
from a National Junior College Athletic Association (NJCAA)
affiliated institution or a community college.
Participants were given the option to answer “Other”
in regard to their primary sport affiliation as well. From
these responses, baseball and softball were retained, while
those who answered tennis, track and field, and cross
country were eliminated. Participants that stated they work
with baseball and softball, were retained because there is
a greater chance their sport uses natural grass and
artificial turf field surfaces. Participants that stated
they work tennis, track and field, and cross country were
eliminated because their primary sport does not utilize
natural grass or artificial turf. Gender, years certified,
collegiate governing body affiliation, primary sport
association, and NATA District association were all
examined. The frequencies are reported in the following
tables.

Table 1: Frequency Table for Gender
Gender
Frequency
Male
Female

Percent

100

61.3

63

38.7

16
Table 2: Frequency Table for Years Certified
Years Certified
Frequency

Percent

1-5

40

24.5

2-10

44

27.0

11-15

21

12.9

16-20

22

13.5

21-25

16

9.8

25-30

14

8.6

31+

6

3.7

Table 3: Frequency Table for Collegiate Governing Body
Affiliation
Location
Frequency
Percent
NCAA Division I

46

28.2

NCAA Division II

30

18.4

NCAA Division III

45

27.6

NAIA I

10

6.1

NAIA II

9

5.5

23

14.1

Other

Table 4: Frequency Table for Primary Sport Affiliation
Sport
Frequency
Percent
Football

64

39.3

Men’s Soccer

33

20.2

Men’s Lacrosse

7

4.3

Men’s Field Hockey

0

0.0

27

16.6

Women’s Lacrosse

8

4.9

Women’s Field Hockey

5

3.1

19

11.7

Women’s Soccer

Other

17
Table 5: Frequency Table for NATA District Affiliation
NATA District
Frequency
Percent
District 1

22

13.5

District 2

21

12.9

District 3

21

12.9

District 4

29

17.8

District 5

16

9.8

District 6

9

5.5

District 7

7

4.3

District 8

13

8.0

District 9

19

11.7

District 10

6

3.7

18

Hypothesis Testing

The following hypotheses were tested in this study.
The level of significance for each hypothesis was tested
using a ≤ .05 significance level.
Hypothesis 1: Athletic Trainers’ will identify
artificial turf to play a significant role in causing lower
limb injuries when compared to natural grass. Risk was rated
utilizing the following scale: -2=Significantly Lower Risk,
-1=Moderately Lower Risk, 0=Same Amount of Risk,
1=Moderately Higher Risk, 2=Significantly Higher Risk.
To determine if Athletic Trainers’ identify artificial
turf to play a significant role in causing lower limb
injuries compared to natural grass, an overall perceived
risk score was calculated. Table 6 below illustrates the
perceived risk mean scores by lower limb injury location
and overall risk.

19
Table 6: Perceived Risk Scores by Injury Location
Lower Limb Injuries
Mean (SD)
Foot Injuries

.28 (.714)

Ankle Injuries

.07 (.813)

Knee Injuries

.44 (.721)

Hip Injuries

.06 (.512)

Back Injuries

.15 (.524)

Overall Risk

.199 (.4648)

Risk was rated utilizing the following scale: -2= Significantly Lower
Risk, -1= Moderately Lower Risk, 0= Same Amount of Risk, 1=Moderately
Higher Risk, 2=Significantly Higher Risk

Conclusion: Based on the overall risk (.199) score,
Athletic Trainers’ do not significantly perceive artificial
turf to play a significant role in lower limb injuries.
Even though there is no significance, it should be noted
that the perceived risk means in Table 6 all lean towards
the higher risk than the lower risk.

Hypothesis 2: There will be no difference in Certified
Athletic Trainers’ perceived risk of lower limb injuries
that occur on artificial turf versus natural grass in
different collegiate governing bodies.
A one-way ANOVA was used to determine whether
differences existed between Certified Athletic Trainers’
and their perceptions of lower limb injuries that occur on
artificial turf versus natural grass based on their

20
collegiate governing body affiliation. The mean scores for
each division are found in Table 7.
Table 7: Mean Injury Risk by Collegiate Governing Body
Collegiate Governing
N
Mean (SD)
Body
NCAA Division I

46

.278 (.4452)

NCAA Division II

30

.120 (.3881)

NCAA Division III

45

.218 (.4509)

NAIA I

10

.100 (.3559)

NAIA II

9

.222 (.6741)

23

.139 (.5766)

Other

Risk was rated utilizing the following scale: -2= Significantly Lower
Risk, -1= Moderately Lower Risk, 0= Same Amount of Risk, 1=Moderately
Higher Risk, 2=Significantly Higher Risk

Conclusion:

The means for the perceived risk of

artificial turf from each collegiate division affiliation
were compared using a one-way ANOVA. No significant
difference was found (F(5,157)=.620,p>.05).

Hypothesis 3: There will be no difference in Certified
Athletic Trainers’ perceived risk of lower limb injuries
that occur on artificial turf versus natural grass by
gender.
The mean scores for each gender were calculated and
can be found in Table 8.

An independent sample t-test was

21
used to determine if the perceptions of lower limb injuries
on artificial turf versus natural grass varied by gender.

Table 8: Independent Sample T-Test Comparing the Mean Risk
Scores Between Male and Female Certified Athletic Trainers’
Gender
n
Mean (SD)
t
P
Male

100

.246 (.3917)

Female

63

.124 (.5570)

1.643

.102

Risk was rated utilizing the following scale: -2= Significantly Lower
Risk, -1= Moderately Lower Risk, 0= Same Amount of Risk, 1=Moderately
Higher Risk, 2=Significantly Higher Risk

Conclusion: An independent-samples t-test was
calculated comparing the mean risk scores between male
Certified Athletic Trainers’ and female Certified Athletic
Trainers’. No significant difference was found
(t(161)=1.643,p>.05). The mean risk score for males was not
significantly different from the mean risk score for
females.

Hypothesis 4: There will be no difference in Certified
Athletic Trainers’ perceived risk of lower limb injuries
that occur on artificial turf versus natural grass based on
years certified.
Mean scores for the different age ranges can be found
in Table 9. A one-way ANOVA was used to determine the
perceptions of Certified Athletic Trainers’ in regard to

22
lower limb injuries that occur on artificial turf versus
natural grass based on years certified. The results from
the one-way ANOVA are displayed below on Table 9.
Table 9: Mean Risk Scores by Years Certified
Years Certified
N

Mean (SD)

1-5

40

.180 (.3674)

2-10

44

.195 (.5274)

11-15

21

.171 (.4303)

16-20

22

.100 (.6377)

21-25

16

.475 (.4123)

25-30

14

.114 (.2905)

31+

6

.267 (.2422)

Risk was rated utilizing the following scale: -2= Significantly Lower
Risk, -1= Moderately Lower Risk, 0= Same Amount of Risk, 1=Moderately
Higher Risk, 2=Significantly Higher Risk

Conclusion: The means for the perceived risk of
artificial turf based on years certified was compared using
a one-way ANOVA. No significant difference was found
(F(6,156)=.289,p>.05).

Additional Findings

Several other tests were conducted using the
demographic section of the questionnaire in conjunction
with the opinion questions.
A one-way ANOVA was used to determine the perceptions
a Certified Athletic Trainer has in regards to lower limb

23
injuries that occur on artificial turf versus natural grass
based on their primary sport. This was examined to
determine if different sports have an increased or
decreased perceived risk in regards to lower limb injuries
on artificial turf.
Conclusion: The means for the perceived risk of
artificial turf based on years certified was compared using
a one-way ANOVA. No significant difference was found
(F(6,156)=.062,p>.05). The results from the one-way ANOVA
are displayed below on Table 9.

Table 10: Mean Risk Scores by Primary Sport
Sport
N

Mean (SD)

Football

64

.181 (.4272)

Men’s Soccer

33

.261 (.4911)

Men’s Lacrosse

7

.086 (.5757)

Men’s Field Hockey

0

.000 (.0000)

27

.319 (.4161)

Women’s Lacrosse

8

.075 (.3991)

Women’s Field Hockey

5

-.400 (.9695)

19

.232 (.3215)

Women’s Soccer

Other

Risk was rated utilizing the following scale: -2= Significantly Lower
Risk, -1= Moderately Lower Risk, 0= Same Amount of Risk, 1=Moderately
Higher Risk, 2=Significantly Higher Risk

To determine the perception a Certified Athletic
Trainer has in regards to lower limb injuries that occur on

24
artificial turf versus natural grass based on their NATA
District affiliation, a one-way ANOVA test was conducted.
Conclusion: The means for the perceived risk of
artificial turf based on NATA District affiliation was
compared using a one-way ANOVA. No significant difference
was found (F(9,153)=.296,p>.05). Table 10 provides the mean
scores for each District.

Table 11: Mean Risk Scores by NATA Districts
NATA District
N

Mean (SD)

District 1

22

.209 (.3115)

District 2

21

.305 (.4588)

District 3

21

.333 (.5598)

District 4

29

.117 (.5113)

District 5

16

.062 (.4717)

District 6

9

.067 (.1732)

District 7

7

.486 (.4140)

District 8

13

.015 (.4356)

District 9

19

.221 (.4158)

District 10

6

.267 (.7554)

Risk was rated utilizing the following scale: -2= Significantly Lower
Risk, -1= Moderately Lower Risk, 0= Same Amount of Risk, 1= Moderately
Higher Risk, 2= Significantly Higher Risk

Further, the researcher asked the participants a
variety of perception questions. The tables below display
the frequencies of these questions. Table 12 shows that
natural grass was perceived to be attributable to the least

25
amount of injuries. For acute contact injuries, a vast
majority of the participants found there to be no
difference in field surface in relationship to acute
contact injuries.
To determine if Certified Athletic Trainers’ perceive
weather on different field surfaces to impact lower limb
injuries, the participants were asked to choose which field
surface was safer for participation during rainy, snowy,
and cold weather. In general, artificial turf was perceived
to be safer than natural grass during inclement weather
(Table 13). Table 14 displays the frequency for which
surface Certified Athletic Trainers’ perceived to be safer.
With 43.6% of the participants choosing natural grass to be
safer, 24.5% choosing artificial turf, and 31.9% claiming
there is no difference between field surfaces, the data
from Table 14 compared to Table 6 show that participants
were consistent in perceiving artificial turf to have
slightly more risk for athletic participation.
Additionally, the participants were asked to identify
which type of field surface their primary sport utilized
during practice and games, the condition of their field,
the measures taken to prevent injuries, and what field
surface they perceived specific injuries to occur more
often. Table 15 shows which type of field surface the

26
participant’s primary sport utilizes during practice and
games and Table 16 displays the perceived condition of the
participant’s field surface. The participants were asked to
check all the measures they have taken to prevent injuries
during supervision of their primary sport. The participants
that answered “Other” stated that they implement prevention
exercise programs, utilize orthopedic braces, employ proper
stretching programs, and make use of warm-up protocols.
These results can be found in Table 17.
In order to determine if any injury patterns existed
on natural grass or artificial turf, the participants were
asked to choose which field surface they perceived specific
injuries to occur more often. Table 18 shows that turf toe
(67.5%) and shin splints (58.9%) were the only injuries to
be chosen to occur more often on artificial turf than
natural grass or no difference. In general, the
participants perceived artificial turf to be injury
inducing overall except for lateral and medial ankle
sprains.

27
Table 12: Frequency Table for Certified Athletic Trainers’
Perception of Different Field Types and Their Role in
Different Injury Categories
Field Surface Acute Non-Contact Acute Contact
Chronic

Natural Grass
Artificial
Turf
No Difference

N (Percent)

N (Percent)

N (Percent)

32 (19.6)

21 (12.9)

23 (14.1)

65 (39.9)

29 (17.8)

80 (49.1)

66 (40.5)

113 (69.3)

60 (69.3)

Table 13: Frequency Table of Certified Athletic Trainers’
Perceptions of Which Field Surface is Safer for Athletes to
Practice and Compete on During Inclement Weather
Field Surface
Rainy Weather Snowy Weather
Cold Weather

Natural Grass
Artificial
Turf
No Difference

N (Percent)

N (Percent)

N (Percent)

34 (20.9)

44 (27.0)

43 (26.4)

88 (54.0)

62 (38.0)

52 (32.5)

41 (25.2)

56 (34.4)

65 (39.9)

Table 14: Frequency Table for Certified Athletic Trainers’
Overall Perception of Which Field Surface is Safer
Field Surface
N (Percent)
Natural Grass

71 (43.6)

Artificial Turf

40 (24.5)

No Difference

52 (31.9)

28
Table 15: Frequency Table for Certified Athletic Trainers’
Field Surface Utilization During Practice and Games
Practice
Games
Field Surface
N (Percent)
N (Percent)
AstroTurf
11 (6.7)
11 (6.7)
FieldTurf

62 (38.0)

61 (37.4)

Natural Grass

85 (52.1)

86 (52.8)

I do not know

0 (0.0)

1 (.6)

Other

5 (3.1)

4 (2.5)

Table 16: Frequency Table for Certified Athletic Trainers’
Perceived Condition of Their Field Surface
Field Condition
N (Percent)
Excellent

63 (38.7)

Good

78 (47.9)

Poor

22 (13.5)

Table 17: Frequency Table for Preventive Measures Taken by
Certified Athletic Trainers’ While Supervising Their
Primary Sport
Field Surface
N (Percent)
Recommended proper footwear
based on field surface
Inspected field for
irregularities
Acclimated athlete(s) to new
field surface
Other

136 (83.4)
116 (71.2)
45 (27.6)
11 (6.7)

29
Table 18: Frequency Table for Certified Athletic Trainers’
Perceptions on the Field Surface Associated with Specific
Lower Limb Injuries
Artificial
Natural Grass
No Difference
Injury
Turf
N (Percent)
N (Percent)
N (Percent)
Turf Toe
7 (4.3)
110 (67.5)
46 (28.2)
Jones
10 (6.1)
31 (19.0)
121 (74.2)
Fracture
Lateral Ankle
52 (31.9)
13 (8.0)
98 (60.1)
Sprain
Medial Ankle
31 (19.0)
17 (10.4)
115 (70.6)
Sprain
High Ankle
25 (15.3)
44 (27.0)
94 (57.7)
Sprain
Shin Splints
23 (14.1)
96 (58.9)
44 (27.0)
ACL N-C
15 (9.2)
69 (42.3)
78 (47.9)
Injuries
ACL Contact
15 (9.2)
24 (14.7)
124 (76.1)
Injuries
MCL N-C
14 (8.6)
41 (25.2)
108 (66.3)
Injuries
MCL Contact
14 (8.6)
18 (11.0)
130 (79.8)
Injuries
LCL N-C
11 (6.7)
25 (15.3)
126 (77.3)
Injuries
LCL N-C
14 (8.6)
13 (8.0)
136 (83.4)
Injuries
Meniscal
20 (12.3)
49 (30.1)
94 (57.7)
Injuries
Hip Injuries
14 (8.6)
23 (14.1)
125 (76.7)
Lower Back
15 (9.2)
44 (27.0)
103 (63.2)
Injuries
Tibia-Fibula
Stress Fx
N-C= Non-Contact

15 (9.2)

59 (36.2)

86 (52.8)

30

DISCUSSION

This study has produced a number of findings related
to the perceived risk that playing surface may have on
athletic injury.

The following section will discuss these

findings and is divided into the following subsections:
Discussion of Results, Conclusions, and Recommendations.

Discussion of Results

This study focused on Certified Athletic Trainers’
perceptions in regards to lower limb injuries that occur on
artificial turf versus natural grass. The researcher
examined different demographic information such as gender,
collegiate division affiliation, and years certified to see
if it affected their perceptions of lower limb injuries
that occur on natural grass versus artificial turf.
The researcher’s first hypothesis was that Athletic
Trainers’ would identify artificial turf to play a
significant role in causing lower limb injuries when
compared to natural grass. There was no previous research
performed that examined the perceptions Certified Athletic
Trainers’ have about lower limb injuries on natural grass

31
and artificial turf. Based on the researchers own
experiences and intuition, it was thought that artificial
turf would play a significant role in causing lower limb
injuries. However, no significant results were shown to
support this hypothesis. With a lack of significance to
show that artificial turf is more dangerous than natural
grass, the results from this study supports the research
conducted by Meyers et al2.
The second hypothesis examined in this study stated
that there will be no difference in the perceptions of
lower limb injury risk that occur on artificial turf versus
natural grass by Certified Athletic Trainers’ in different
collegiate governing bodies. The researcher hypothesized
that an institution affiliated with a higher division such
as NCAA Division I may be able to afford a higher quality
playing surface than an institution in a lower division. A
high quality playing surface would provide a more
consistent field surface, which could help eliminate lower
limb injuries and alter Certified Athletic Trainers’
perceptions. Although the results did show a perception
that artificial turf is slightly not as safe natural grass,
Certified Athletic Trainers’ from different collegiate
governing bodies did perceive lower limb injury risk that
occurs on artificial turf versus natural grass similar

32
manner. The results support this hypothesis even though no
significance was found in the first hypothesis.
The third hypothesis stated by the researcher was that
Certified Athletic Trainers’ of different genders will
perceive lower limb injury risk that occurs on natural
grass versus artificial turf the same. With current
research involving gender difference in regards to lower
limb injuries, it was thought that Certified Athletic
Trainers of different gender could potentially have
different perceptions of lower limb injuries that occur on
natural grass versus artificial turf. Results showed that
the perceived mean risk score for the males was .246 and
.124 for females. The significance level for the t-test was
.056. The hypothesis of no difference in perceived risk is
supported by these results.
The researcher’s final hypothesis stated that there
will be no difference in perceptions of lower limb injuries
that occur on natural grass versus artificial turf
regardless of how many a Certified Athletic Trainer has
been certified. With artificial turf evolving from a carpet
like AstroTurf to grass like FieldTurf, it was thought that
individuals that have been certified longer may have a
different perception of lower limb injuries that occur on
natural grass versus artificial turf. Nonetheless, the

33
results did not show any significant difference between
perceptions based on the number of years an individual has
been a Certified Athletic Trainer. It is interesting to
note that the 16 Athletic Trainers’ that have been
certified for 21-25 years had a perceived mean risk score
of .475. This is more than double the overall perceived
risk score for all the participants. However, the results
from the one-way ANOVA still support the hypothesis of no
difference in perception of risk due to the number of years
certified.
In addition to examining the hypotheses, the
researcher discovered additional findings by using
supplementary demographic and perception questions. These
additional findings were made using perceived mean risk
scores and frequencies.
The first additional finding used Certified Athletic
Trainers’ from different sports to determine if perception
on lower limb injuries that occur on natural grass versus
artificial turf altered. The significance level for the
one-way ANOVA used to measure the relationship for this
additional finding was .062, deeming it insignificant.
However, the highest perceived mean risk score of .319 was
recorded by 27 Certified Athletic Trainers’ who work with
women’s soccer and the lowest of -.400 came from the 5

34
Certified Athletic Trainers’ who stated they work with
women’s field hockey.
Beyond examining the different primary outdoor sport a
Certified Athletic Trainer works with, NATA District was
examined to determine if Certified Athletic Trainers’
perceptions change based on their location. Once again, no
significance was discovered from the one-way ANOVA. NATA
District 7(Arizona, Colorado, New Mexico, Utah, and
Wyoming) displayed the highest perceived mean risk of .486.
Whereas, NATA District 8(California, Hawaii, and Nevada)
displayed the lowest perceived risk of .015. These
comparisons of perceived mean risks are interesting because
the two districts are relatively close to each other.
The results of this study both support and oppose the
results of previous studies. Although the overall results
did not demonstrate that athletic trainers perceive
artificial turf to be less safe than natural grass, it did
not show artificial turf to be perceived more dangerous
either. Certified Athletic Trainers did not perceive ankle
injuries to have a significant perceived mean risk score,
which did not defend the findings that ankle injuries occur
more often on artificial turf than natural grass as found
by Steffen et al and Ekstrand et al.3,

4

Additionally, the

findings in Table 18 show medial and lateral ankle sprains

35
were perceived to occur more often on natural grass
compared to artificial turf. These perceptions are contrary
to the findings by Steffen et al and Ekstrand et al.3,

4

In

addition, Meyers found FieldTurf to safer than natural
grass, which was not displayed by Certified Athletic
Trainers’ perceptions.1

Conclusions

There were no significant differences found between
Certified Athletic Trainers from different collegiate
governing bodies, gender, years certified, NATA Districts,
and primary sports in the amount of injury risk they
perceive due to athletic turf surface. Based on the results
of this study, we can conclude that Certified Athletic
Trainers’ have similar perceptions of lower limb injuries
that occur on natural grass versus artificial turf.
Regardless of collegiate governing body, gender, years
certified, sport, and NATA District, Certified Athletic
Trainers’ do not significantly perceive artificial turf to
be more dangerous than natural grass in regards to lower
limb injuries. This could be a credit to the evolution of
artificial turf, development of proper footwear, and/or
proper training for a specific sport.

36

Recommendations

The results of this study demonstrate that, in
general, Certified Athletic Trainers’ agree that there is
no significant difference between the potential lower limb
injury risks on natural grass versus artificial turf. In
order to aid in determining if field surfaces play a role
in lower limb injuries, future research could obtain the
perceptions of athletes through a survey similar to the one
used in this study.
In addition, further research should track lower limb
injuries by field surface, sport, collegiate governing
body, gender, shoe manufacturer, and weather conditions.
This would give a better outlook as to whether or not field
surface play a significant role in lower limb injuries and
also determine if there is a difference between Certified
Athletic Trainers’ perceptions and actual injury
prevalence.

A large prospective study examining these

factors would help guide Certified Athletic Trainers in
preventing injuries that might be due to the shoe-surface
interface.

37

REFERENCES

1.

Meyers M. Incidence, mechanisms, and severity of
game-related college football injuries on FieldTurf
versus natural grass: a 3-year prospective study. AM
J SPORT MED. April 2010;38(4):687-697.

2.

Meyers M, Barnhill B. Incidence, causes, and
severity of high school football injuries on
FieldTurf versus natural grass: a 5-year prospective
study. AM J SPORT MED. October 2004;32(7):1626-1638.

3.

Steffen K, Andersen T, Bahr R. Risk of injury on
artificial turf and natural grass in young female
football players. BRIT J SPORT MED. August 2007;41
Suppl 1:i33-i37.

4.

Ekstrand J, Timpka T, Hägglund M. Risk of injury in
elite football played on artificial turf versus
natural grass: a prospective two-cohort study. BRIT
J SPORT MED. December 2006;40(12):975-980.

5.

Villwock M, Meyer E, Powell J, Fouty A, Haut R.
Football playing surface and shoe design affect
rotational traction. AM J SPORT MED. March
2009;37(3):518-525.

6.

Powell J, Schootman M. A multivariate risk analysis
of selected playing surfaces in the National
Football League: 1980 to 1989. An epidemiologic
study of knee injuries. AM J SPORT MED. November
1992;20(6):686-694.

7.

Hagel B, Fick G, Meeuwisse W. Injury risk in men's
Canada West University football. AM J EPIDEMIOL. May
1, 2003;157(9):825-833.

8.

Orchard J. Is there a relationship between ground
and climatic conditions and injuries in football?
SPORTS MED. 2002;32(7):419-432.

9.

Orchard J, Powell J. Risk of knee and ankle sprains
under various weather conditions in American

38
football. MED SCI SPORT EXER. July 2003;35(7):11181123.
10. Queen R, Charnock B, Garrett W, Hardaker W, Sims E,
Moorman C. A comparison of cleat types during two
football-specific tasks on FieldTurf. BRIT J SPORT
MED. April 2008;42(4):278-284.
11. Ford K, Manson N, Evans B, et al. Comparison of inshoe foot loading patterns on natural grass and
synthetic turf. J Sci Med Sport. December
2006;9(6):433-440.
12. Heidt R, Dormer S, Cawley P, Scranton P, Losse G,
Howard M. Differences in friction and torsional
resistance in athletic shoe-turf surface interfaces.
AM J SPORT MED. November 1996;24(6):834-842.
13. de Noronha M, Refshauge K, Herbert R, Kilbreath S,
Hertel J. Do voluntary strength, proprioception,
range of motion, or postural sway predict occurrence
of lateral ankle sprain?. BRIT J SPORT MED. October
2006;40(10):824-828.

39

APPENDICES

40

APPENDIX A
Review of Literature

41

REVIEW OF LITERATURE

On a yearly basis, an increasing number of collegiate
athletic teams are converting from natural grass to
artificial turf surfaces. Although the initial costs are
high, the reduced time and money spent in maintaining
artificial turf is second to none. In order to understand
the potential healthcare benefits and/or risks of
artificial turf compared to natural grass it is important
to examine the perceptions athletic trainers have about
lower body injuries that occur on each type of surface.
The purpose of this Review of Literature is to analyze
how athletic trainers perceive the prevalence of lower body
injuries that occur on natural grass versus artificial
turf. This will be accomplished in the following sections:
Bony and Ligamentous Anatomy, Risk Factors, Artificial
Versus Natural Grass, and Preventative Measures. The review
of literature will end with a summary of the research
performed to date.

42

Bony and Ligamentous Anatomy
Reviewing the literature as it pertains to anatomy is
important to highlight the structures that are at risk with
lower limb injuries. With the ankle and knee commonly
injured during athletic participation, the following
sections will describe some of the structures that an
individual may injure.

Ankle
The distal end of the tibia and fibula, the talus, and
the calcaneus are all bones that make up the ankle.1 The
superior and inferior tibiofibular joints, the talocrural
joint, and the subtalar joint are all made up by the
articulations between those bones. The distal end of the
tibia and the lateral malleolus make up the inferior
tibiofibular joint. The talocrural joint, which is a hinge
joint, is formed by the distal tibia, the trochlea surface
of the talus, and the medial malleolus. Dorsiflexion and
plantar flexion occurs at this joint. The articulation
between the calcaneus and talus forms the subtalar joining.1
Movements that occur at the joint include inversion,
eversion, pronation and supination.

43
There are many ligaments that provide static support
at the ankle. The lateral ligaments include the anterior
talofibular ligament (ATF), posterior talofibular ligament
(PTF), and the calcaneofibular ligament (CF).1 On the medial
side there is one major ligament called the deltoid
ligament.1 This ligament resists eversion and although it
has four parts to it, it is still considered to be one
ligament.

Knee
The knee joint consists of the femur, tibia, fibula,
and the patella. It is one of the most traumatized joints
among the physically active population due to the extreme
stresses exerted on it.1 The articulations that exist at the
knee include; the superior tibiofibular joint, the patella
femoral joint, and the tibiofemoral joint.
Within the articulations of the knee lie many
ligamentous and essential structures. On top of the
articular facets of the tibia are menisci. The medial
meniscus is “C” shaped, whereas the lateral meniscus is “O”
shaped.1 Both provide a larger articulation surface between
the tibia and femur, absorb pressure, and stabilize the
knee. Along with the meniscus, there are four major
ligaments that assist in stabilizing the knee.

The two

44
cruciate ligaments cross each other as they travel through
the joint cavity of the knee.1 The anterior cruciate
ligament (ACL) aids in preventing the femur from
translating posteriorly during weight bearing.1 The ACL
stabilizes the tibia against excessive internal rotation
and serves as a secondary restraint for varus and valgus
forces as well. The posterior cruciate ligament (PCL)
resists hyperextension of the knee and femur. On the medial
aspect of the knee lies the medial collateral ligament
(MCL). The MCL is the primary restraint against valgus
forces and excessive external rotation. The MCL crosses the
medial joint line attaching on the medial epicondyle of the
femur and below on the tibia. Additionally, a portion of
the MCL attaches to the medial meniscus. The lateral
collateral ligament (LCL) attaches from the lateral
epicondyle of the femur to the head of the fibula. The LCL
primary resists varus forces that act on the knee. The
foot, ankle, knee, and hip all compose the lower limb
kinetic chain and when forces act on the foot and ankle it
can

cause additional stress at the knee joint, which may

lead to injury.

45

Risk Factors

Athletes from all sports are susceptible to injuries
at any given time and many times it is too late for them to
prevent the injury from occurring. The literature reviewed
in the following sub-sections will look at shoe-surface
traction and predisposing factors as being risk factors
associated with lower body injuries. Being able to identify
injury risks will justify further research and enable
individuals to take the necessary actions to prevent
injuries.

Shoe-Surface Traction
Not only does the type of surface affect injury risk,
but the shoes utilized by athletes matter as well. In most
cases, a positive correlation exists between shoe-surface
traction and ground hardness.2 There is a higher risk for
the incidence of injury due to an increased surface
hardness and shoe-surface traction. Orchard et al looked at
numerous articles to discover that shoe-surface traction
will be elevated on hard and dry natural grass when grass
cover and root density are at their maximum.2 Plus, cleat

46
length contributes to the amount of shoe-surface traction
an individual exhibits.
In addition, cold weather is associated with an
increased lower limb injury rate for knee and ankle sprains
on both artificial turf and natural grass.3 The higher rate
of lower limb injuries is explained with a decrease in
shoe-surface traction. In order to have the right amount of
traction, a balance between shoe and surface types must be
determined.
Furthermore, footwear should be selected on the amount
of rotational traction and surface type to help decrease
the probability of possible lower limb injury. Villwock et
al examined ten different types of football shoes on four
different types of field surfaces: artificial turf,
FieldTurf, AstroPlay, and natural grass. With the use of a
mobile testing apparatus that applied rotational force and
measured torque at the shoe-surface interface the
researchers were able to collect data on actual surface
installations. Both artificial turf surfaces demonstrated a
greater rotational torque when compared to the natural
grass surfaces.4 A greater rotational torque can augment the
likelihood of lower limb injuries. Most importantly, the
turf-style cleat significantly exhibited the lowest amount
of torque compared to ten different shoe models.4 With

47
artificial surfaces evolving, it is important to continue
to conduct shoe and surface experiments to optimize an
athlete’s performance and reduce the risk of injury.
To reduce injuries on both natural grass and
artificial surfaces it is important to select proper
footwear. A cleat with more spikes may need to be selected
in order to reach desired shoe to surface traction when
cold weather creates a hard surface. A natural grass field
with maximum grass cover and root density may require a
cleat with longer spikes to reduce shoe to surface
traction. Shoe selection for artificial turf is just as
important as well, knowing that a rotational torque on
FieldTurf and AstroPlay is greater than natural grass
surfaces.4 A balance between safety and performance must be
determined when selecting shoes for a specific surface in
order to achieve the lowest amount of injury risks and the
highest amount of athlete success.

Predisposing Factors
Beyond worrying about shoe to surface traction, it is
also important to look at risk factors that may predispose
an athlete to a lower limb injury. de Noronha et al
conducted a systematic review of twenty-one research
studies, aimed to determine if voluntary strength,

48
proprioception, range of motion, or postural sway could
predict the occurrence of lateral ankle sprains. From the
initial results a lack of dorsiflexion was determined to be
the biggest risk factor in predicting lateral ankle
sprains.5
Moreover, Trojian and McKeag used a single leg balance
test to predict ankle sprains in 230 male and female
athletes from one high school and three colleges.

Main

results showed individuals were at risk for future ankle
sprains when a positive single leg balance test was
observed. The researchers also observed an even higher risk
of ankle sprains when athletes did not tape their ankles.6
Trojian and McKeag were able to claim the single leg
balance test as a valid test for predicting ankle sprains.6
Additionally, foot characteristics can be a predictor
for lateral ankle sprains as well. Morrison and Kaminski
looked at high longitudinal arches, greater foot widths,
cavovarus foot deformities, women with increased open chain
calcaneal eversion range of motion, greater
metatarsophalangeal joint extension, and a more laterally
situated gait.7 After Morrison and Kaminski reviewed the
literature, they concluded that more reliable measurement
techniques should be developed and utilized to better

49
understand the relationship between foot characteristics
and lateral ankle sprains.7
Further, an athlete may be at risk for lower limb
injuries based on factors other than their anatomical and
mechanical structure of their bodies. Hagel et al looked at
men’s varsity football players in the Canada West
Universities Athletic Association for five years to
determine the injury risk factors. From the results Hagel
et al collected, injury rates were high during competition
compared to practice periods.8 Lower extremity injury rates
during games were greater on artificial turf than on
natural grass during both wet and dry field conditions.
From the research performed by Hagel et al, they were able
to conclude that the risk factors for injuries included,
but were not limited to participation during games, being a
veteran player, playing on artificial turf, and having a
previous history of injuries.8

Previous Artificial Turf Versus Natural Grass Studies

Due to the evolution of artificial turf, a vast amount
of studies are being developed to determine if each new
artificial turf is safer than natural grass. Many of these
studies take into account, in-shoe to surface loading, the

50
frequency of injuries, the mechanisms of the injuries, and
the severity of the injuries. The following sections will
be broken into comparisons of artificial turf versus
natural grass based on injuries, shoe to surface loading,
and artificial turf comparisons.

Injuries
Long before artificial turf began to evolve into what
it is today, AstroTurf existed and widely became the
popular choice for many collegiate and professional teams.
To determine if AstroTurf increased the incidence of lower
limb injuries, Powell et al used a multivariate risk
analysis to compare the risk factors associated with injury
rates by position in the National Football League on
different playing surfaces. The collected data showed a
significant statistical difference between the higher
injury rates for knee sprains on AstroTurf and natural
grass.9 When knee sprains are divided into MCL and ACL
sprains, only the ACL injuries show a higher injury rate on
AstroTurf compared to natural grass. The researchers were
able to conclude that AstroTurf increased the risk of
anterior cruciate ligaments for National Football League
players from the years 1980-1989.9

51
As artificial turf became popular, Tartan turf was
created. Tartan turf eventually became a competitor of
AstroTurf.

AstroTurf and Tartan turf were primarily the

same type of artificial turf. A retrospective and
prospective comparative study was performed to compare
injuries that occurred on Tartan turf and natural grass at
the University of Wisconsin.10 Retrospective data was
collected through 235 questionnaires that were returned by
athletes who played from 1960 to 1973. Prospective data was
collected through examination of injured athletes from 1975
to 1977. Results showed a significantly higher amount of
serious injuries such as sprains and ligament tears that
were sustained on natural grass compared to minor scrapes
that occurred on the Tartan turf.10 In conclusion, the
researchers suggested that athletes may be returning to
play on grass fields too quickly following the occurrence
of an injury.
FieldTurf is now the dominant choice of artificial
turf for all levels of competition in many different
sports. To compare the incidence, causes, and severity of
high school football injuries on FieldTurf versus natural
grass, Meyers et al utilized a prospective cohort study
during a five year period with eight high schools. Results
showed an injury incidence rate of 15.2 per ten team games

52
on FieldTurf compared to 13.9 per ten team games on natural
grass.11 Meyers et al concluded that although the injury
rates were similar between FieldTurf and natural grass,
each surface displayed distinctive injury patterns that
merit further research.11
When the prevalence of injuries during competition was
examined, Meyers hypothesized that a difference did not
exist between FieldTurf and natural grass.12 The study
Meyers conducted utilized twenty four Division I collegiate
football teams to quantify the incidence, mechanisms, and
severity of collegiate football game related injuries
during a span of three years. To accomplish this, a
prospective cohort study was used with a two-sided single
page injury surveillance form.12 When data analysis
concluded, FieldTurf was determined to be safer than
natural grass when comparing game related injuries.12 It
should also be noted that a bias of results is a limitation
of this study because the research performed was funded by
FieldTurf.
Many other sports utilize artificial turf as well,
which is why Steffen et al conducted a prospective cohort
study. Subjects for this study consisted of 2,020 young
female football athletes from 109 different teams. The
results showed a higher incidence of ankle sprains on

53
artificial turf even though more games and overall injuries
were documented on natural grass.13 Similar results were
found in a two cohort study performed by Ekstrand et al.
Ekstrand et al looked at 290 male European club football
players who competed and trained on artificial turf, where
the control group consisted of 202 male Swedish Premier
League players.14 Overall, results showed no difference
between the incidences of injuries that occurred on
artificial turf versus natural grass, but similar to the
study conducted by Steffen et al; a higher rate of ankle
sprains was reported on artificial turf.13,14

Shoe-Surface Loading
In addition to determining what type of field surface
is safer from an injury standpoint, researchers have found
importance in studying the differences between in-shoe
loading patterns on both artificial turf and natural grass
as well. Ford et al used seventeen male football players to
test in-shoe foot loading patterns while performing cutting
actions in a slalom course.15 The results of the study
showed that artificial turf had significantly higher peak
pressures within the central forefoot and lesser in the
toes when compared to the natural grass.15 In contrast, the
medial forefoot and lateral midfoot exhibited higher

54
relative loads. There was no difference in maximal effort
sprint times. The authors of this study concluded that
different playing surfaces alter the amount of plantar
force and that further research should be conducted to
determine sport specific injuries.15
A study completed by Queen et al aimed to examine the
effect of different cleat plate configurations on plantar
pressure during a cross cut and side cut.

The subjects for

this study consisted of thirty-six healthy athletes who
participated in a cleated sport at least twice a week. All
of the subjects were asked to run a course five times
wearing four different styles of the Nike Vitoria cleats to
that included: bladed, elliptical firm ground, hard ground
and turf.

Pressure was measured using Pedar-X insoles.16

After data was examined, an observed significant variance
in forefoot loading patterns existed among cleat types. The
researchers suggest that it might be advantageous to
increase the forefoot cushioning in cleats to help decrease
forefoot loading.16
Along with testing loading patterns, a study conducted
by Heidt et al examined the shoe-surface interaction of
fifteen football shoes made by three different
manufacturers in both anterior translation and rotation
using a specially designed pneumatic testing system.17 All

55
shoes were tested under a twenty-five pound axial load on
synthetic turf both wet and dry and on natural stadium
grass. The authors also noted that the spatting of a
football shoe resulted in a reduction of forces generated
for both translation and rotation. The authors of this
study determined that improper footwear for specific field
surfaces impose a higher level of injury risk.17 Moreover,
it was also recommended that shoe manufacturers display
suggested indications and ideal surface use for which their
shoes are intended.

Artificial Turf Comparisons
Additionally, due to the evolution of artificial turf
surfaces, it is essential to compare the different types of
artificial turf. To test five different types of
professionally used football turf an instrumented
computerized impact recording device was used to test for
increased or decreased impact attenuation. The impact
recording device was dropped twenty times from a height of
four feet on each surface type. The results of the study
showed no significant difference between older foam turf
and new rubber shredded based turf.18 However, there were
locations within the shredded based turf that was compacted
in which it became a harder surface when compared to the

56
older foam turf. This research concluded that impact
attenuation has not been altered with the production of
newer shredded rubber based turf.18

Preventive Measures

There are many different options an individual can
take to decrease the probability of a lower limb injury.
Utilizing ankle taping and bracing, proprioception
training, and shoe selection are a few of several ways an
individual can help prevent a lower limb injury.
Taping and bracing have long been used to help reduce
the incidence of ankle sprains in athletes. When Kadakia
and Haddad reviewed eight studies, they looked at the role
of ankle bracing and taping in secondary prevention of
ankle sprains in athletes. After reviewing the literature
they determined that that there is enough biomechanical
evidence that supports the mechanical advantage of semirigid orthoses for restriction of inversion and eversion at
the ankle after prolonged and brief stages of exercise.19 It
was also noted that the current experimental data validates
that any taping and bracing is effective in reducing the
incidence of secondary ankle sprains.19 Taping and bracing
are both reasonable options when attempting to prevent

57
ankle sprains, but primary prevention of ankle sprains
should be examined at as well.
Proprioception is often used when treating individuals
for ankle sprains. A review article constructed by Eils
aimed to discover the role of proprioception in the primary
role of preventing ankle sprains in athletes. From eight
studies, Eils was able to conclude that even though
proprioception programs are favored in primary ankle sprain
prevention for healthy subjects, there is no evidence that
supports these proprioception prevention programs.20
However, it was noted that a proprioception program can be
promising for individuals with a history of ankle sprains.20
Prevention of ankle sprain may not even involve bracing,
taping, and/ or proprioception, but rather the
biomechanical aspects of an artificial turf.
Moreover, a review article by Dixon et al, takes a
multidisciplinary approach by looking at the artificial
turf properties from a sports medicine, engineering and
biomechanics point of view. To optimize the sports medicine
field it is necessary for the engineering field to approach
artificial turf on a sport specific basis to help reduce
injuries.21 In conclusion the author recommends shoe and
surface companies to work together to develop an ideal shoe
and surface for a specific group of athletes.21

58

Summary

The technology and advancement of artificial turf has
created many different variables that one must account for
when choosing to participate on a desired field surface.
While many believe artificial turf improves athletic
performance and is safer, others argue that traditional
natural grass still prevails over man-made synthetic field
surfaces. Every year there are new teams at each athletic
level that convert to artificial turf for a variety of
reasons. As more and more teams do begin to utilize
artificial turf it is important that the athletic training
society continues to remain aware of the possible health
risks.
To ensure athletes can reach their fullest potential
of athletic performance while remaining safe, it is
imperative that research continues to better understand the
potential risks involved with artificial turf
participation. Everything from shoes to playing experience
must be considered when determining the variables that
contribute to lower limb injuries on different field
surfaces. More research must be embarked upon to remain at

59
the same level of progression as the artificial turf
market.

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APPENDIX B
The Problem

61

THE PROBLEM

Statement of the Problem
The primary scope of this study is to determine if
Certified Athletic Trainers in the collegiate setting
perceive a difference in lower limb injuries that occur on
artificial turf versus natural grass.

There have been

conflicting reports about whether artificial turf impacts
lower limb injuries more compared to natural grass.

Some

research shows artificial turf to be safer while others
have found it to be unsafe or have no difference compared
to artificial turf.

A study performed by Meyers et al

showed that the injury rate between artificial turf and
natural grass were similar, but each displayed distinctive
injury patterns that merit further research.

It is

important to know the perceptions of Certified Athletic
Trainers in regards to lower limb injuries that occur on
artificial turf versus natural grass because they will
provide an unbiased opinion that will determine if further
research is necessary.

62

Definition of Terms
The following terms will be operationally defined for
this study:
1)

Collegiate Athletic Trainer – Individuals that
are identified by the National Athletic Trainers’
Association as working in a collegiate
environment.

2)

Artificial Turf – Any outdoor field surface that
is manufactured with synthetic fibers to look
like natural grass.

3)

Natural Grass – Any outdoor surface that consists
of grass that is imbedded into soil.

4)

Primary Sport- The sport that an athletic trainer
spends a majority of their time with.

Basic Assumptions
The following are basic assumptions of this study:
1)

All survey questions were answered honestly,
unbiased, and to the best of the ability of the
athletic trainer.

2)

No other individuals, except the participants
will be completing the survey at their own free
will.

63
3)

The sample obtained for research best represents
the athletic training population as a whole.

4)

All participants are Certified Athletic Trainers’
identified by the NATA.

Limitations of the Study
The following are possible limitations of the study:
1)

The quality of natural grass surfaces may vary
based on climatic changes.

2)

The participants may not know what type of field
surface their institution has.

3)

Not all Certified Athletic Trainers’ surveyed
work with an outdoor sport as their primary sport
coverage.

4)

The email address for the selected participants
may no longer be valid.

5)

The participants may no longer work in a
collegiate setting.

Delimitation of the Study
The following statement reflects the delimitations of
the study:
1)

Only collegiate athletic trainers will be
surveyed.

64
2)

All artificial turf types will be grouped
together due to the vast amount of manufacturers.

3)

The validity of the survey instrument has yet to
be established.

Significance of the Study
The primary scope of this study is to examine the
collegiate Certified Athletic Trainers’ perceptions
regarding the prevalence of lower limb injuries that occur
on artificial turf versus natural grass. Knowing how
athletic trainers perceive an increase in lower limb
injuries that occur on artificial turf or natural grass may
influence a collegiate institutions decision to install
artificial turf or natural grass.

In addition, based on

the results of the study, further research may be deemed
necessary to further look at the relationship between lower
limb injuries and field surfaces.

65

APPENDIX C
Additional Methods

66

APPENDIX C1
Institutional Review Board –
California University of Pennsylvania

67

68

69

70

71

72

73

74

75

76

77
Institutional Review Board
California University of Pennsylvania
Psychology Department LRC, Room 310
250 University Avenue
California, PA 15419
instreviewboard@cup.edu
instreviewboard@calu.edu
Robert Skwarecki, Ph.D., CCC-SLP,Chair

Mr. Wildenhain,
Please consider this email as official notification that your proposal titled
Certified Athletic Trainers Perceptions of Lower Limb Injuries that Occur on
Natural Grass versus Artificial Turf” (Proposal #10-032) has been approved
by the California University of Pennsylvania Institutional Review Board as
submitted.
The effective date of the approval is 02-15-2011 and the expiration date is
02-14-2012. These dates must appear on the consent form.
Please note that Federal Policy requires that you notify the IRB promptly
regarding any of the following:
(1) Any additions or changes in procedures you might wish for your study
(additions or changes must be approved by the IRB before they are
implemented)
(2) Any events that affect the safety or well-being of subjects
(3) Any modifications of your study or other responses that are necessitated
by any events reported in (2).
(4) To continue your research beyond the approval expiration date of 02-142012 you must file additional information to be considered for continuing
review. Please contact instreviewboard@calu.edu
Please notify the Board when data collection is complete.
Regards,
Robert Skwarecki, Ph.D., CCC-SLP
Chair, Institutional Review Board

78

APPENDIX C2
Survey

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80

81

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83

84

85

86

87

88

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APPENDIX C3
Cover Letter

91
Dear Fellow Certified Athletic Trainer,
I am a master’s degree candidate at California University of Pennsylvania, requesting your
assistance to complete part of my degree requirements. The primary purpose of this study is to
examine the perceptions athletic trainers have about lower limb injuries that occur on natural
grass versus artificial turf.
This student survey is not approved or endorsed by NATA. It is being sent to you because of
NATA’s commitment to athletic training education and research.
The questionnaire consists of two sections. The first section is comprised of demographic
questions and the second section contains perception questions as they pertain to lower limb
injuries that occur on artificial turf versus natural grass.
A random sample of 1000 Certified Athletic Trainers’ working in the collegiate setting from the
National Athletic Trainers’ Association have been asked to take part in this survey. The California
University of Pennsylvania Institutional Review Board has approved this study for the Protection
of Human Subjects effective 02/14/2011 until 02/15/2012. Completion of the online survey
constitutes informed consent to participate in this study.
Participation within this survey is voluntary. This survey is completely anonymous and upon
submission, neither your name nor email address will be attached to your answers. Your
information will be kept strictly confidential. Further, you will have the option to discontinue
taking the survey at any time without penalty and all data will be discarded.
If at any time you have questions or concerns about the survey you can contact the researcher
by email at wil4430@calu.edu or by telephone at 815.354.5049. If you would like to contact the
research advisor, his name is Tom West and can be contacted by email at west_t@calu.edu or
by telephone at 724.938.5933.
As a fellow certified athletic trainer, your knowledge and opinions regarding this topic makes
your input invaluable. Please take a few minutes to complete the survey by clicking on the link
below.
https://www.surveymonkey.com/s/8VL8JB9
Thank you for your time and consideration,
Ryan JD Wildenhain, ATC, PES
Graduate Athletic Training Education Program
California University of Pennsylvania
250 University Avenue
California, Pennsylvania 15419
Participants for this survey were selected at random by the NATA membership database
according to the selection criteria by the student doing this survey. This student survey is not
approved or endorsed by NATA. It is being sent to you because of NATA’s commitment to athletic
training education and research.

92

APPENDIX C4
Pilot Study Results

93
Table 19: Pearson Product Moment Correlation for Pilot
Study Results
Question #
Pearson Correlation
Significance
Q13

.111

.745

Q14

.049

.886

Q15

.090

.793

Q16

.000

1.000

Q17

.570

.067

Q18

.734

.010

Q19

.510

.109

Q20

-.418

.200

Q22

-.179

.599

Q24

.467

.148

Q25

.707

.015

Q26

.690

.019

Q27

.719

.013

Q28

.517

.103

Q29

.575

.064

Q30

.538

.088

Q31

.266

.429

Q32

.329

.324

Q33

.442

.173

Q34

.405

.216

Q35

.337

.311

Q36

.329

.324

Q37

.705

.015

Q38

.064

.852

Q39

.467

.148

94

REFERENCES

1.

Prentice W. Arnheim’s Principles of Athletic Training
A Competency-Based Approach. 11th ed. New York, NY:
McGraw –Hill Companies, Inc.; 2003.

2.

Orchard J. Is there a relationship between ground and
climatic conditions and injuries in football? SPORTS
MED. 2002;32(7):419-432.

3.

Orchard J, Powell J. Risk of knee and ankle sprains
under various weather conditions in American football.
MED SCI SPORT EXER. July 2003;35(7):1118-1123.

4.

Villwock M, Meyer E, Powell J, Fouty A, Haut R.
Football playing surface and shoe design affect
rotational traction. AM J SPORT MED. March
2009;37(3):518-525.

5.

de Noronha M, Refshauge K, Herbert R, Kilbreath S,
Hertel J. Do voluntary strength, proprioception, range
of motion, or postural sway predict occurrence of
lateral ankle sprain?. BRIT J SPORT MED. October
2006;40(10):824-828.

6.

Trojian T, McKeag D. Single leg balance test to
identify risk of ankle sprains. BRIT J SPORT MED. July
2006;40(7):610-613.

7.

Morrison K, Kaminski T. Foot Characteristics in
Association With Inversion Ankle Injury. J ATHL
TRAINING. January 2007;42(1):135-142.

8.

Hagel B, Fick G, Meeuwisse W. Injury risk in men's
Canada West University football. AM J EPIDEMIOL. May
1, 2003;157(9):825-833.

9.

Powell J, Schootman M. A multivariate risk analysis of
selected playing surfaces in the National Football
League: 1980 to 1989. An epidemiologic study of knee
injuries. AM J SPORT MED. November 1992;20(6):686-694.

95
10.

Keene J, Narechania R, Sachtjen K, Clancy W. Tartan
Turf on trial. A comparison of intercollegiate
football injuries occurring on natural grass and
Tartan Turf. AM J SPORT MED. January 1980;8(1):43-47.

11.

Meyers M. Incidence, mechanisms, and severity of gamerelated college football injuries on FieldTurf versus
natural grass: a 3-year prospective study. AM J SPORT
MED. April 2010;38(4):687-697.

12.

Meyers M, Barnhill B. Incidence, causes, and severity
of high school football injuries on FieldTurf versus
natural grass: a 5-year prospective study. AM J SPORT
MED. October 2004;32(7):1626-1638.

13.

Steffen K, Andersen T, Bahr R. Risk of injury on
artificial turf and natural grass in young female
football players. BRIT J SPORT MED. August 2007;41
Suppl 1:i33-i37.

14.

Ekstrand J, Timpka T, Hägglund M. Risk of injury in
elite football played on artificial turf versus
natural grass: a prospective two-cohort study. BRIT J
SPORT MED. December 2006;40(12):975-980.

15.

Ford K, Manson N, Evans B, et al. Comparison of inshoe foot loading patterns on natural grass and
synthetic turf. J Sci Med Sport. December
2006;9(6):433-440.

16.

Queen R, Charnock B, Garrett W, Hardaker W, Sims E,
Moorman C. A comparison of cleat types during two
football-specific tasks on FieldTurf. BRIT J SPORT
MED. April 2008;42(4):278-284.

17.

Heidt R, Dormer S, Cawley P, Scranton P, Losse G,
Howard M. Differences in friction and torsional
resistance in athletic shoe-turf surface interfaces.
AM J SPORT MED. November 1996;24(6):834-842.

18.

Naunheim R, Parrott H, Standeven J. A comparison of
artificial turf. J Trauma. December 2004;57(6):13111314.

96

19.

Kadakia A, Haddad S. The role of ankle bracing and
taping in the secondary prevention of ankle sprains in
athletes. INT SPORTMED J. September 2003;4(5):1-10.

20.

Eils E. The role of proprioception in the primary
prevention of ankle sprains in athletes. INT SPORTMED
J. September 2003;4(5):1-9.

21.

Dixon S, Batt M, Collop A. Artificial playing surfaces
research: a review of medical, engineering and
biomechanical aspects. Int J Sports Med. May
1999;20(4):209-218.

97
Abstract
Title:

CERTIFIED ATHLETIC TRAINERS PERCEPTIONS
OF LOWER LIMB INJURIES THAT OCCUR ON
NATURAL GRASS VERSUS ARTIFICIAL TURF

Researcher:

Ryan J.D. Wildenhain, ATC, NASM-PES

Advisor:

Thomas F. West, PhD, ATC

Date:

April 2011

Research Type:

Master’s Thesis

Context:

There have been conflicting reports
about whether artificial turf impacts
lower limb injuries more compared to
natural grass. Some research shows
artificial turf to be safer while
others have found it to be unsafe or
have no difference compared to
artificial turf.

Objective:

The primary scope of this study is to
determine if Certified Athletic
Trainers’ (ATC’s) in the collegiate
setting perceive a difference in lower
limb injuries that occur on artificial
turf versus natural grass.

Design:

Descriptive Survey

Setting:

Population-Based Survey

Participants:

1000 randomly selected ATC’s currently
working in the collegiate setting. The
final response rate was 269 with 163
utilized for data analysis.

Interventions:

The dependent variable was the
perceived relationship of lower limb
injuries that occur on natural grass
versus artificial turf by ATC’S. The
independent variables included an
Athletic Trainers’ gender, years
certified, collegiate governing body
affiliation, and playing surface.

98

Main Outcome Measures:
Perceived risk was measured with the
following scale: -2= Significantly Lower
Risk, -1= Moderately Lower Risk, 0=
Same Amount of Risk, 1=Moderately
Higher Risk, 2=Significantly Higher
Risk.
Results:

The overall perceived mean risk score
of .199 was considered insignificant.
The significance level from a one-way
ANOVA between ATC’s overall perceived
mean risk score and a collegiate
governing body was deemed insignificant
at .685. A t-test was calculated
comparing the mean risk scores between
male Certified Athletic Trainers’ and
female Certified Athletic Trainers’.
The results of the t-test showed the
.056 significance level to be
insignificant. A one-way ANOVA
determined the number of years and
Athletic Trainer to be certified did
not play a role in altering their
perceptions of lower limb injuries that
occur on natural grass versus
artificial turf. The significance level
for this one-way ANOVA was .289.

Conclusion:

There were no significant differences
found between Certified Athletic
Trainers’ from different collegiate
governing bodies, gender, years
certified, NATA Districts, and sports.
Based on the results of this study, we
can conclude that Certified Athletic
Trainers’ have similar perceptions of
lower limb injuries that occur on
natural grass versus artificial turf.

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