Shoulder Injuries Among United States High
School Athletes During the 2005–2006 and
2006–2007 School Years
John E. Bonza, MPH*; Sarah K. Fields, JD, PhD*; Ellen E. Yard, MPH?;
R. Dawn Comstock, PhD*?
*The Ohio State University, Columbus, OH;3The Research Institute at Nationwide Children’s Hospital, Columbus, OH
Context: The shoulder is one of the most commonly injured
body sites among athletes. Little previous research describes
shoulder injury patterns in high school athletes.
Objective: To describe and compare shoulder injury rates
and patterns among high school athletes in 9 sports (football,
soccer, basketball, baseball, and wrestling for boys and soccer,
volleyball, basketball, and softball for girls).
Design: Prospective injury surveillance study.
Setting: Injury data were collected from 100 nationally
representative US high schools via High School Reporting
Patients or Other Participants: Athletes from participating
high schools injured while involved in a school-sanctioned
practice or competition in 1 of the above sports during the 2005–
2006 and 2006–2007 school years.
Main Outcome Measure(s): Shoulder injury rates, diagno-
ses, severity, and mechanisms.
Results: During the 2005–2006 and 2006–2007 school
years, athletes in this study sustained 805 shoulder injuries
during 3550141 athlete-exposures (AEs), for an injury rate of
2.27 shoulder injuries per 10000 AEs. This corresponds to an
estimated 232258 shoulder injuries occurring nationwide during
this time. Shoulder injuries were more likely to occur during
competition than practice (rate ratio 5 3.01, 95% confidence
interval 5 2.62, 3.46). Shoulder injury rates per 10000 AEs
were highest in football (5.09), wrestling (4.34), and baseball
(1.90). Common shoulder injury diagnoses included sprains/
strains (39.6%), dislocations/separations (23.7%), contusions
(11.5%), and fractures (6.6%). Although 44.8% of athletes
sustaining a shoulder injury returned to play in less than 1 week,
22.9% were out of play for more than 3 weeks, and 6.2% of
shoulder injuries required surgery. Common mechanisms of
shoulder injury included player-to-player contact (57.6%) and
contact with the playing surface (22.8%).
Conclusions: High school shoulder injury rates and patterns
varied by sport. Continued surveillance is warranted to
understand trends and patterns over time and to develop and
evaluate evidence-based preventive interventions.
Key Words: epidemiology, injury surveillance
The shoulder injury rate was 2.27 per 10000 athlete-exposures.
Shoulder injuries were more likely to occur during competition than practice.
Shoulder injury rates were highest in football, wrestling, and baseball.
Common shoulder injury diagnoses included sprains/strains, dislocations/separations, contusions, and fractures.
health,2athletes are at risk for sport-related injuries. With
participation rates in high school sports on the rise,1the
number of student-athletes exposed
shoulder injuries is likely to increase unless effective
preventive interventions are developed.
Shoulder injuries are the fifth most common injury
among high school athletes.3The majority of shoulder
injuries result from participation in contact sports such as
football, in which high-speed collisions and falls are
common.4 However, chronic-overuse shoulder injuries
can occur in sports that require the shoulder to perform
similar motions repeatedly.5Negative effects of shoulder
injury can range from a significant reduction in playing
time to lifelong shoulder instability or shoulder degener-
ation over time.
ore than half of all US high school students
compete on school athletic teams.1 Although
sport participation promotes fitness and better
Authors of previous shoulder injury studies have focused
on specific sports,4,6–13the mechanics of the shoulder in
body sites in several sports,3,18–20diagnosis of different types
of shoulder injuries,5,21,22or comparisons of surgical proce-
dures in treating different shoulder injuries.8,23,24To date, no
researchers have described and compared shoulder injury
rates and patterns across sports using a nationally represen-
tative sample of high school athletes.
Our study goal was to describe and compare the
epidemiology of shoulder injuries among US high school
athletes participating in 9 highschool sports(football, soccer,
basketball, baseball, and wrestling for boys and soccer,
representative sample. The specific aims were to (1) calculate
shoulder injury rates during the 2005–2006 and 2006–2007
academic years, (2) describe shoulder injury patterns, and (3)
compare shoulder injury rates and patterns by sport and sex.
Journal of Athletic Training
gby the National Athletic Trainers’ Association, Inc
76Volume 44 N Number 1 N February 2009
Understanding the epidemiology of shoulder injuries is an
important first step in developing targeted, evidence-based
interventions to reduce such injuries.
Reporting Information Online (RIO; The Research
Institute at Nationwide Children’s Hospital, Columbus,
OH), an Internet-based, sports-related injury surveillance
system, captured injuries during the 2005–2006 and 2006–
2007 school years from 100 nationally representative US
high schools. The study methods have been described in
detail previously.25–30Briefly, eligible schools (ie, US high
schools with a National Athletic Trainers’ Association
[NATA]–affiliated certified athletic trainer [AT] willing to
serve as reporter) were categorized by geographic loca-
tion31and school size (enrollment less than or equal to
1000 students or more than 1000 students). Schools were
then randomly selected from each stratum to obtain a
nationally representative study sample of 100 study
schools. If a school dropped out of the surveillance study,
a replacement school from the same sampling stratum was
enrolled. Participating ATs logged into RIO weekly to
report injury and exposure data in 9 high school sports
(football, soccer, basketball, baseball, and wrestling for
boys and soccer, volleyball, basketball, and softball for
Definition of Injury and Exposure
An athlete-exposure (AE) consisted of 1 athlete partic-
ipating in 1 practice or competition. An injury met all of the
following criteria: (1) occurred as a result of participation
in an organized high school practice or competition, (2)
required medical attention by an AT or a physician, and (3)
resulted in restriction of the student-athlete’s participation
for at least 1 day beyond the day of the injury. If multiple
injuries were sustained during the same injury event, the
AT was instructed to use his or her opinion as a sports
medicine professional to identify and report only the most
serious injury. For each injury, a detailed injury report
describing characteristics of the injured player (eg, age,
year in school), the injury (eg, site, diagnosis, severity), and
the event leading to the injury (eg, mechanism, presence of
illegal activity) was completed by the AT. Although the
surveillance system captured 29 distinct injury diagnoses,
for the purposes of this study, shoulder injury diagnoses
were categorized as sprains/strains (including incomplete
and complete ligament sprains, muscle strains, and tendon
strains), dislocations/separations, contusions, fractures,
and other (ie, all other injury diagnoses accounting for
less than 5% of all injuries, such as stress fracture and
tendinitis). Because all reporters were trained sports
medicine professionals, diagnoses, whether made by a
physician or an AT, were based on accepted clinical
standards. Throughout the study, ATs were able to view all
data they submitted and update reports as required (eg,
need for surgery, days until return to play). Efforts to
ensure high-quality data included weekly data audits
during the study and an internal validity check after the
first year of data collection.
Data were analyzed using SPSS (version 14.0; SPSS Inc,
Chicago, IL) and Epi Info (version 6.0; Centers for Disease
Control and Prevention, Atlanta, GA). All rate calculations
and rate comparisons used unweighted injury counts.
Additional analyses used a weighting factor to produce
national estimates, with the standard errors for comparison
among sports and between sexes adjusted for the High School
RIO sampling plan using the SPSS Complex Samples module.
This weighting factor was based on the inverse probability of
selection into the study sample, taking into account the total
number of US schools by sampling stratum and by sport.
Relative standard errors (RSEs), calculated as the standard
error of the national estimate divided by the national estimate
itself, are presented to demonstrate the reliability of these
estimates. A higher RSE indicates less stability, and RSEs
higher than 30% are potentially unreliable.
Injury rates were calculated as the ratio of injuries per
10000 AEs. Rate ratios (RRs) and proportion ratios (PRs)
were calculated with 95% confidence intervals (CIs). An RR
or PR greater than 1.00 indicates a risk association, whereas
an RR or PR less than 1.00 indicates a protective
association. Confidence intervals not including 1.00 were
considered statistically significant. The following are exam-
ples of an RR calculation comparing the rate of competition
shoulder injuries to the rate of practice shoulder injuries and
a PR calculation comparing the overall proportion of
shoulder fractures among boys and girls, respectively:
RR~ No: competition shoulder injuries=
No: competition AEsÞ|10000?
7 No: practice shoulder injuries=
No: practice AEsÞ|10000?
PR~ National estimated No: boys,shoulder fractures=
National estimated total No: boys,shoulder injuriesÞ?
7 National estimated No: girls,shoulder fractures=
National estimated total No: girls,shoulder injuriesÞ?
This study was approved by the Institutional Review Board
During the 2005–2006 and 2006–2007 school years,
athletes in this study sustained 805 shoulder injuries during
3550141 AEs, for an injuryrate of 2.27 shoulder injuries per
10000 AEs in sampled sports (Table 1). These 807 injuries
correspond to an estimated 232258 shoulder injuries
occurring nationwide during this period. Overall, shoulder
injuries accounted for 8.0% of all injuries sustained by high
school athletes. Shoulder injuries made up the greatest
proportionof all injuries in boys’baseball (17.7%), wrestling
(17.5%), and football (11.7%) and in girls’ softball (10.4%).
Most shoulder injuries occurred during the playing season
(72.0%); however, 24.6% occurred during preseason.
Shoulder injuries were assessed solely by ATs 45.4% of the
time, by ATs and physicians 27.8% of the time, solely by
Journal of Athletic Training77
physicians 25.9% of the time, and by another medical
professional the remaining 1.0% of the time.
Overall, shoulder injuries were 3 times more likely to
occur during competition (4.41 per 10000 AEs) than during
practice (1.46 per 10000 AEs) (RR 5 3.01, 95% CI 5 2.62,
3.46) (Table 1). Only volleyball had a higher shoulder injury
rate during practice than competition. The highest shoulder
injury rates per 10000 AEs occurred in football (5.09),
wrestling (4.34), and baseball (1.90) for boys and in softball
(1.10) and volleyball (1.07) for girls. Shoulder injuries were
13 times more likely to occur in football, the sport with the
highest shoulder injury rate, than in girls’ soccer, the sport
with the lowest rate (RR 5 12.9, 95% CI 5 7.28, 22.9)
(Table 2). In the 3 boys’ sports with the highest injury rates,
shoulder injuries were more likely to occur in football than
in baseball (RR 5 2.68, 95% CI 5 2.07, 3.47), but
differences between football and wrestling, the sports with
the highest shoulder injury rates, were not significant (RR 5
1.17, 95% CI 5 0.97, 1.41). Among girls, shoulder injuries
were more likely to occur in softball, the sport with the
highest shoulder injury rate, than in soccer (RR 5 2.79, 95%
CI 5 1.42, 5.49) and basketball (RR 5 2.46, 95% CI 5 1.33,
4.54). However, differences between softball and volleyball
were insignificant (RR 5 1.03, 95% CI 5 0.61, 1.72).
When considering sex differences in comparable sports
(ie, soccer, basketball, and baseball/softball), boys had a
higher shoulder injury rate (0.95 per 10000 AEs) than girls
(0.61 per 10000 AEs) (RR 5 1.55, 95% CI 5 1.12, 2.15).
More specifically, boys’ baseball had a higher shoulder
injury rate than girls’ softball (RR 5 1.73, 95% CI 5 1.11,
2.69); boys’ soccer had a higher rate than girls’ soccer (RR
5 1.45, 95% CI 5 0.70, 2.98), although it was statistically
insignificant; and girls’ basketball had a similar rate to
boys’ basketball (RR 5 1.06, 95% CI 5 0.55, 2.04).
The RSEs were fairly low in most sports: football (3.9%),
(23.0%), boys’ basketball (24.2%), boys’ soccer (27.7%), and
girls’ basketball (27.8%). Because of a relatively high RSE in
girls’ soccer (44.5%), analyses using nationally estimated girls’
soccer shoulder data should be interpreted cautiously.
Common shoulder injury diagnoses included sprains/
strains (39.6%), dislocations/separations (23.7%), contu-
States, 2005–2006 and 2006–2007 School Years
Shoulder Injury Rates by Sport and Exposure Type, National High School Sports–Related Injury Surveillance Study, United
Sport Exposure Typen Athlete-Exposures
Injury Rate (per 10000
Rate Ratio (95%
5.97 (4.98, 7.15)
Boys’ soccer3.94 (1.55, 10.7)
3.01 (1.23, 7.53)
3.34 (2.40, 4.65)
Boys’ baseball1.46 (0.89, 2.38)
Girls’ soccer4.70 (1.42, 17.9)
Girls’ volleyball 300.58 (0.23, 1.31)
16Girls’ basketball2.41 (0.87, 6.67)
1.61 (0.75, 3.42)
Girls’ sports 1.54 (1.00, 2.36)
Boys’ sports 3.58 (3.09, 4.15)
Overall3.01 (2.62, 3.46)
aPractice was used as the referent category.
78Volume 44 N Number 1 N February 2009
sions (11.5%), and fractures (6.6%) (Figure 1). Other
diagnoses reported included tendinitis (3.5%), nerve
injuries (2.5%), inflammation (2.8%), and torn cartilage
(1.9%). Most shoulder injuries were new (85.2%), with
14.8% being recurrent injuries. Recurrent shoulder injuries
were most common in boys’ basketball (27.0%), baseball
(22.0%), girls’ basketball (18.6%), and softball (18.6%).
all girls’ soccer shoulder injuries), volleyball (58.7%), baseball
separations were most common in girls’ basketball (38.9%),
boys’ soccer (35.7%), football (29.0%), and wrestling (25.8%).
Contusions were most common in girls’ basketball (19.7%),
football (15.9%), and boys’ soccer (15.5%). Fractures were
most common in boys’ soccer (33.7%).
Diagnoses differed by sport and sex, although most
differences between the sexes were not statistically signif-
icant (Figure 1). In soccer, boys sustained a higher
proportion of fractures (PR 5 3.47, 95% CI 5 0.57,
21.1), while girls sustained a higher proportion of sprains/
strains (PR 5 12.9, 95% CI 5 2.79, 59.7). In basketball,
boys sustained a higher proportion of sprains/strains (PR
5 1.43, 95% CI 5 0.36, 5.67), while girls sustained a higher
proportion of dislocations/separations (PR 5 2.69, 95% CI
5 0.56, 13.0). In baseball/softball, softball players had 4
times the proportion of dislocations/separations (PR 5
4.03, 95% CI 5 0.55, 29.8).
Severity of Injury
Although shoulder injuries commonly allowed athletes
to return to play in less than 1 week (44.8%), 22.9% of
injuries kept athletes out of play for more than 3 weeks.
Athletes in volleyball (66.0%), boys’ basketball (60.2%),
girls’ basketball (59.1%), and softball (51.1%) most
frequently returned to play less than 1 week after the
injury (Figure 2). Athletes in girls’ soccer (56.2%), boys’
soccer (49.2%), boys’ basketball (32.0%), and wrestling
(31.8%) most frequently required longer recovery periods
(more than 3 weeks) after their injuries.
Injuries that required time loss of less than 1 week were
(20.9%), and dislocations/separations (15.8%). Disloca-
tions/separations (33.7%), fractures (27.5%), and sprains/
strains (21.2%) were diagnoses that most frequently
resulted in time loss of more than 3 weeks. Surgery was
required for 6.2% of all shoulder injuries, with dislocations/
separations accounting for 53.4% of all surgeries. Sports
with the largest percentage of shoulder injuries requiring
surgery were wrestling (8.5%), girls’ basketball (7.8%), and
Although they were statistically insignificant, potentially
clinically significant sex differences existed. In soccer, time
loss did not vary between boys and girls. Compared with
girls, boys were more likely to miss more than 3 weeks of
playing time in basketball (PR 5 4.13, 95% CI 5 0.49,
34.6) and baseball/softball (PR 5 1.49, 95% CI 5 0.46,
4.79). When combining all 3 sports, boys were more likely
to sustain a shoulder injury requiring surgery (PR 5 1.48,
95% CI 5 0.27, 8.01).
Mechanism of Injury
Common mechanisms of shoulder injuries included
player-to-player contact (57.6%), contact with the playing
surface (22.8%), no contact (eg, improper shoulder
rotation) (10.0%), overuse/chronic (4.6%), and contact
with a playing apparatus (eg, tackling dummy, soccer goal,
basketball hoop) (2.9%). Player-to-player contact was the
primary mechanism for shoulder injuries that required
surgery (59.8% of shoulder injuries requiring surgery),
followed by contact with the playing surface (20.0%).
High School Sports–Related Injury Surveillance Study, United
States, 2005–2006 and 2006–2007 School Years
Shoulder Injury Rate Comparisons by Sport, National
Overall Injury Rate (per
Rate Ratio (95%
12.9 (7.28, 22.9)
11.0 (6.11, 19.9)
4.82 (2.61, 8.93)
2.79 (1.42, 5.49)
2.72 (1.39, 5.31)
1.45 (0.70, 2.98)
1.20 (0.59, 2.45)
1.14 (0.54, 2.40)
aGirls’ soccer was used as the referent category.
Figure 1. Diagnoses of athletes with shoulder injuries by sport and sex, National High School Sports–Related Injury Surveillance Study,
United States, 2005–2006 and 2006–2007 school years. Data are based on weighted national estimates and include competition and
practice exposures.aCaution should be used when interpreting national estimates for girls’ soccer, because they are based on small case
counts and have a relative standard error greater than 30%.
Journal of Athletic Training 79
Player-to-player contact accounted for 58.0% of injuries
resulting in more than 3 weeks of time loss.
Player-to-player contact resulting in shoulder injuries
was most frequently seen in football (76.2% of all football
shoulder injuries), girls’ basketball (66.6%), wrestling
(59.5%), and boys’ soccer (53.2%). Shoulder injuries that
resulted from contact with the playing surface were most
common in girls’ soccer (87.7%), boys’ soccer (45.8%),
wrestling (30.5%), and girls’ basketball (24.6%). Noncon-
tact shoulder injuries were most commonly seen in baseball
(43.7%), volleyball (37.2%), softball (30.2%), and boys’
basketball (13.9%). Shoulder injuries caused by contact
with a playing apparatus were most common in boys’
basketball (30.2%) and volleyball (26.3%).
Sprains/strainswere frequently causedbyplayer-to-player
contact (50.1%), contact with the playing surface (23.5%),
and no contact (17.1%). Dislocations/separations were
frequently caused by player-to-player contact (64.1%) and
contact with the playing surface (29.5%). All contusions
resulted from either player-to-player contact (83.8%) or
contact with the playing surface (16.2%). Similarly, all
fractures resulted from player-to-player contact (56.7%) or
contact with the playing surface (42.3%).
As seen in Table 3, there was little overall difference in
shoulder injury mechanism by sex when combining
comparable sports. However, sport-specific differences
existed. In soccer, boys were more likely to sustain shoulder
injuries after contact with another player (PR 5 5.91, 95%
CI 5 1.07, 32.7), whereas girls were more likely to sustain a
shoulder injury after contact with the playing surface (PR
5 1.92, 95% CI 5 1.00, 3.68). In basketball, boys were
more likely to sustain shoulder injury after contact with a
playing apparatus (PR 5 9.91, 95% CI 5 1.05, 93.2), while
girls were more likely to sustain shoulder injuries after
contact with the playing surface (PR 5 2.90, 95% CI 5
0.51, 16.5) and player-to-player contact (PR 5 1.41, 95%
CI 5 0.74, 2.68), although the latter were statistically
insignificant. In baseball/softball, boys were more likely to
sustain a shoulder injury after contact with the playing
surface (PR 5 3.26, 95% CI 5 0.59, 18.1) or via
noncontact mechanisms (PR 5 1.45, 95% CI 5 0.67,
3.14), while girls sustained a higher proportion of shoulder
injuries as a result of overuse/chronic mechanisms (PR 5
1.38, 95% CI 5 0.50, 3.81) and contact with another player
(PR 5 1.65, 95% CI 5 0.42, 6.47), although these
differences were statistically insignificant.
Specifically, the most common activities leading to
(26.0%), and blocking (20.6%). The most common activities
leading to boys’ soccer shoulder injuries were goaltending
(35.9%), chasing a loose ball (21.7%), and defending
(17.6%). In girls’ soccer, the most common activities leading
to shoulder injuries were ball handling/dribbling (46.2%)
and goaltending (20.4%). In volleyball, the most common
activities leading to injury were serving (44.7%) and spiking
(30.7%). In boys’ and girls’ basketball, the most common
activities leading to shoulder injury were defending (20.9%
and 37.8%, respectively) and rebounding (16.2% and 40.9%,
respectively). In wrestling, takedowns (32.4%), near falls
(15.8%), and sparring (14.1%) caused the majority of
shoulder injuries. In baseball and softball, most shoulder
injuries resulted from throwing (excluding pitching) (24.3%
and 50.2%, respectively), pitching (32.6% and 12.5%,
respectively), and fielding (25.2% and 9.2%, respectively).
In this study, the first in a decade to compare shoulder
injury rates and patterns across 9 high school sports
(football, soccer, basketball, baseball, and wrestling for
boys and soccer, volleyball, basketball, and softball for
girls), we found nearly a quarter of a million shoulder
injuries occurred among high school athletes nationwide
during the 2005–2006 and 2006–2007 school years. Shoulder
injury rates and patterns varied by sport and sex. With more
than half of all US high school students competing in high
school sports,1it is important to understand sport-specific
shoulder injury patterns to assist coaches, ATs, physicians,
and policy makers in developing targeted interventions to
prevent shoulder injuries in this population.
Shoulder injuries occurred at an overall rate of 2.27 per
10000 AEs (4.41 for competition and 1.46 for practice).
Figure 2. Time loss due to shoulder injury by sport and sex, National High School Sports–Related Injury Surveillance Study, United
States, 2005–2006 and 2006–2007 school years. Data are based on weighted national estimates and include competition and practice
exposures.aIncludes season-ending and career-ending injuries.bIncludes injuries with which the athlete continued playing and for which
the athlete had surgery after the season or injuries with which the athlete continued playing, but with modified activities to accommodate
the injury.cCaution should be used when interpreting national estimates for girls’ soccer, because they are based on small case counts
and have a relative standard error greater than 30%.
80Volume 44 N Number 1 N February 2009
This is less than half the shoulder injury rate reported in a
prior study3of high school athletes (5.4). Additionally, the
percentage of all injuries accounted for by shoulder injuries
was slightly lower in our study (8.1%) than in the prior
study (10.2%).3Part of this decrease may be due to study
design variables, such as a slightly broader definition of
injury in the previous study or differences in the relative
amount of competition and practice exposures between
studies. However, at least part of this decrease is likely due
to improved prevention efforts (eg, protective equipment,
practice methods, rule modifications) and improvements in
early diagnosis and treatment of minor injuries that may
prevent more serious time-loss shoulder injuries.5,8,14,21,24,32
For example, new detection methods for rotator cuff tears
have led to multiple arthroscopic techniques for shoulder
In our study, the sports in which shoulder injuries
accounted for large proportions of total injuries (baseball,
wrestling, football, and softball) were also shown recently
to have high percentages of shoulder injuries at the
collegiate level.12,13,33,34Similar to our findings, collegiate
shoulder injuries are predominately sprains/strains and
tendinitis,12,13,33–35with football and wrestling shoulder
injuries often resulting from player-to-player contact,
whereas baseball and softball injuries occurred most often
from noncontact mechanisms.12,13,33,35Also similar to our
findings, shoulder injuries in collegiate baseball often
resulted in longer periods of time loss than did collegiate
softball shoulder injuries.12,13
Shoulder injury rates in this study were higher in
competition than in practice for 8 of the 9 sports studied.
This result confirms findings previously reported at both
the high school and collegiate levels and was expected, as
competitions tend to be more physically demanding, with
greater risk taking and, thus, higher injury rates.12,33,36
Volleyball was the exception, with a 1.7 times greater
shoulder injury rate in practice. Although this finding is
similar to that of a previous study3in which volleyball
injury rates were 2.3 times greater in practice than
competition, prior results have been inconsistent, with at
least one previous group37reporting no difference between
collegiate practice and competition volleyball shoulder
injury rates. One potential explanation for the difference
between volleyball and the other sports studied may be the
no-contact nature of volleyball competitions. Additionally,
compared with competitions, volleyball practices consist of
many more repetitions of various skills, such as serving,
spiking, and blocking, that may lead to chronic and
overuse injuries as well as acute injuries.
Shoulder injury rates were highest in football and
wrestling, sports with frequent player-to-player contact
and frequent impacts with the playing surface. This result is
consistent with the findings of Powell and Barber-Foss.3
Shoulder injury rates were also high in baseball, softball,
and volleyball. Although baseball, softball, and volleyball
tend not to involve the player-to-player contact associated
Basketball, and Baseball/Softball), National High School Sports–Related Injury Surveillance Study, United States, 2005–2006 and 2006–
2007 School Yearsa
Shoulder Injury Diagnosis, Injury Mechanism, Year in School, and Need for Surgery for Sports Played by Both Sexes (Soccer,
Boys, % (n 5 36213)Girls, % (n 5 22727) Proportion Ratio (95% Confidence Interval)b
1.24 (0.78, 1.98)
1.62 (0.66, 4.00)
1.25 (0.32, 4.86)
4.32 (0.86, 21.7)
1.33 (0.65, 2.74)
Contact with playing surface
Contact with playing apparatus
1.18 (0.58, 2.41)
1.03 (0.53, 2.02)
1.59 (0.74, 3.45)
1.19 (0.42, 3.37)
10.9 (1.25, 95.0)
4.93 (0.90, 27.1)
Year in school
1.82 (0.76, 4.36)
1.39 (0.55, 3.56)
1.01 (0.55, 1.84)
1.67 (0.88, 3.17)
1.48 (0.27, 8.01)
aData based on weighted national estimates and include competition and practice exposures.
bBolded group used as referent (for example: for sprains/strains, boys were used as the referent group).
cOther diagnoses accounting for less than 5% of all injuries (eg, stress fracture, tendinitis).
dNo-contact mechanisms include improper shoulder rotation, etc.
Journal of Athletic Training81
with football and wrestling, continued stress on the
shoulder as a result of repetitive movements in these sports
likely plays a crucial role in shoulder injury.7,9,10,17
Sport-specific preventive interventions incorporated into
the practice setting may reduce the high competition
shoulder injury rates. For example, because most football
shoulder injuries were sustained while the players were
tackling or blocking, football coaches should emphasize
proper tackling and blocking techniques during practice.
Similarly, wrestling coaches should focus on safe, effective
takedown maneuvers. Because athletes in baseball, softball,
and volleyball typically spend large amounts of practice
time performing repetitive motions that involve the
shoulder (eg, throwing, pitching, serving, spiking), coaches
and ATs in these sports should ensure that players do not
overuse their shoulders. One way to do this may be to place
increased emphasis on the quality of the player’s technique
rather than the number of repetitions.34 Continued
research in developing high-quality, impact-attenuating
protective gear (such as football shoulder pads that lessen
the force of high-impact blows to the shoulder) could also
be effective in decreasing shoulder injury rates in contact
Consistent with prior research,3shoulder injury rates in
soccer, basketball, and baseball/softball were higher among
boys than girls (0.95 and 0.61 per 10000 AEs, respectively).
This could be due to boys using their shoulders more
forcibly and more often in contact situations.
We found that 6.2% of all shoulder injuries required
surgery, with boys who sustained a shoulder injury being
48% more likely to require surgery than girls. This
comparison was statistically insignificant, but this finding
is likely clinically important. Because dislocations/separa-
tions accounted for almost half of all shoulder surgeries,
research focusing on causes and preventive interventions
for shoulder dislocations and/or separations would have a
large effect in decreasing the high monetary and participa-
tion-related cost of shoulder surgeries.
Shoulder injury patterns differed within sex-comparable
sports. In soccer, girls were more likely to sustain sprains/
strains, and their shoulder injuries were more likely to
result from contact with the playing surface. Conversely,
boys were more likely to sustain fractures, and their
shoulder injuries were more likely to result from player-to-
player contact, indicating that boys may be more likely to
use their shoulders during aggressive, physical play.24In
basketball, boys were more likely than girls to incur
shoulder injuries resulting from contact with a playing
apparatus. In baseball/softball, boys were more likely to
sustain shoulder injuries from contact with the playing
Because males and females differ both in shoulder
anatomy and in the way they use their shoulders, coaches
and ATs should consider implementing shoulder strength
and flexibility programs that are sex, sport, and position
specific. For example, because the pitching motion is very
different between baseball and softball, and because
baseball and softball pitchers put different stresses on their
shoulders compared with their teammates, baseball and
softball pitchers would likely benefit from tailored shoulder
strength and flexibility programs. In addition, continued
research to identify the biomechanics leading to shoulder
injury among males and females in specific sports should
provide coaches with further insights into preventing these
Like all studies, this study had limitations. Only schools
with an NATA-affiliated AT were eligible for participa-
tion, so the findings may not be generalizable to US high
schools without an AT. However, data quality was
improved by including only trained sports medicine
professionals, NATA-affiliated ATs, as reporters. Our
definition of an AE as a single athlete’s participation in 1
practice or 1 competition is less precise than a time-based
measure. However, our definition was more feasible for
high school ATs, who cannot be present to record minutes
of participation for all athletes in all practices and
competitions in 9 sports, and an athlete is at risk for
injury any time he or she practices or competes. Another
potential limitation was that almost half of all injury
diagnoses were made solely by the AT and not a physician.
Yet because NATA-affiliated ATs are trained sports
medicine professionals, we have confidence in the accuracy
of their diagnoses. Additionally, this study relied on the
reporting AT to choose the most appropriate shoulder
injury diagnosis from the 29 diagnosis categories provided
by the surveillance system. Finally, although we used data
collected from only the first 2 years of a continuing
national study, the nationally estimated number of
shoulder injuries in most sports had RSEs measuring less
than 30%, indicating relatively high data stability. How-
ever, caution should be used when interpreting PRs that
have wide 95% CIs. In particular, the nationally estimated
number of girls’ soccer shoulder injuries has a high RSE
and thus is potentially unstable. However, we believe the
clinical significance of these data outweigh the potential
data instability, as this study presents the largest, most
comprehensive epidemiologic investigation of shoulder
injuries across high school sports to date.
The shoulder is one of the 5 most frequently injured
body sites among high school athletes.3Although sport-
related shoulder injuries will never be completely eliminat-
ed, identifying shoulder injury rates and patterns among
sports will increase our understanding of shoulder injury
risk factors and lead to the development of targeted injury
prevention strategies. Such efforts will provide high school
athletes with the opportunity to compete in sports with
minimized risk of shoulder injury. Thus, continued
surveillance of shoulder injury among high school sports
must be conducted to understand trends, to drive
development and evaluation of evidence-based intervention
strategies, and to gain further knowledge of shoulder
injuries (eg, risk factors for chronic shoulder injuries in
This study was funded in part by the Centers for Disease
Control and Prevention (CDC) grant R49/CE000674-01.
82 Volume 44 N Number 1 N February 2009
The content of this report is solely the responsibility of
the authors and does not necessarily reflect the official
views of the CDC.
1. National Federation of State High School Associations. 2006–07
high school athletics participation survey. http://nfhs.org/core/
October 12, 2007.
2. National Federation of State High School Associations. The case for
high school activities. http://www.nfhs.org/web/2004/01/the_case_for_
high_school_activities.aspx. Accessed February 6, 2007.
a review of the 1995–1997 seasons. J Athl Train. 1999;34(3):277–284.
4. Kaplan LD, Flanigan DC, Norwig J, Jost P, Bradley J. Prevalence
and variance of shoulder injuries in elite collegiate football players.
Am J Sports Med. 2005;33(8):1142–1146.
5. Owens S, Itamura JM. Differential diagnosis of shoulder injuries in
sports. Op Tech Sports Med. 2000;8(4):253–257.
6. Chen FS, Diaz VA, Loebenberg M, Rosen JE. Shoulder and elbow
injuries in the skeletally immature athlete. J Am Acad Orthop Surg.
7. Dahm DL, Lajam CM. Shoulder instability in the female athlete. Op
Tech Sports Med. 2002;10(1):5–9.
8. Nakagawa S, Yoneda M, Mizuno N, Hayashida K, Mac T, Take Y.
Throwing shoulder injury involving the anterior rotator cuff:
concealed tears not as uncommon as previously thought. Arthroscopy.
9. Olsen SJ II, Fleisig GS, Dun S, Loftice J, Andrews JR. Risk factors
for shoulder and elbow injuries in adolescent baseball pitchers.
Am J Sports Med. 2006;34(6):905–912.
10. Sciascia A, Kibler WB. The pediatric overhead athlete: what is the
real problem? Clin J Sport Med. 2006;16(6):471–477.
11. Weldon EJ III, Richardson AB. Upper extremity overuse injuries in
swimming: a discussion of swimmer’s shoulder. Clin Sports Med.
12. Dick R, Sauers EL, Agel J, et al. Descriptive epidemiology of
collegiate men’s baseball injuries: National Collegiate Athletic
Association Injury Surveillance System, 1988–1989 through 2003–
2004. J Athl Train. 2007;42(2):183–193.
13. Marshall SW, Hamstra-Wright KL, Dick R, Grove KA, Agel J.
Descriptive epidemiology of collegiate women’s softball injuries:
National Collegiate Athletic Association Injury Surveillance System,
1988–1989 through 2003–2004. J Athl Train. 2007;42(2):286–294.
14. Baker CL, Merkley MS. Clinical evaluation of the athlete’s shoulder.
J Athl Train. 2000;35(3):256–260.
15. Terry GC, Chopp TM. Functional anatomy of the shoulder. J Athl
16. Werner SL, Guido JA Jr, Stewart GW, McNeice RP, Van Dyke T,
Jones DG. Relationships between throwing mechanics and shoulder
distraction in collegiate baseball pitchers. J Shoulder Elbow Surg.
17. Werner SL, Jones DG, Guido JA Jr, Brunet ME. Kinematics and
kinetics of elite windmill softball pitching. Am J Sports Med. 2006;
18. Boden BP, Tacchetti R, Mueller FO. Catastrophic injuries in high
school and college baseball players. Am J Sports Med. 2004;32(5):
19. Emery CA, Meeuwisse WH. Injury rates, risk factors, and mecha-
nisms of injury in minor hockey. Am J Sports Med. 2006;34(12):
20. Turbeville SD, Cowan LD, Owen WL, Asal NR, Anderson MA. Risk
factors for injury in high school football players. Am J Sports Med.
21. Blevins FT, Hayes WM, Warren RF. Rotator cuff injury in contact
athletes. Am J Sports Med. 1996;24(3):263–267.
22. Moosikasuwan JB, Miller TT, Dines DM. Imaging of the painful
shoulder in throwing athletes. Clin Sports Med. 2006;25(3):vi,
23. Buss DD, Lynch GP, Meyer CP, Huber SM, Freehill MQ.
Nonoperative management for in-season athletes with anterior
shoulder instability. Am J Sports Med. 2004;32(6):1430–1433.
24. Cho NS, Hwang JC, Rhee YG. Arthroscopic stabilization in anterior
shoulder instability: collision athletes versus noncollision athletes.
25. Centers for Disease Control and Prevention (CDC). Sports-related
injuries among high school athletes—United States, 2005–06 school
year. MMWR Morb Mortal Wkly Rep. 2006;55(38):1037–1040.
26. Gessel LM, Fields SK, Collins CL, Dick RW, Comstock RD.
Concussions among United States high school and collegiate athletes.
J Athl Train. 2007;42(4):495–503.
27. Nelson AJ, Collins CL, Yard EE, Fields SK, Comstock RD. Ankle
injuries among United States high school sports athletes, 2005–2006.
J Athl Train. 2007;42(3):381–387.
28. Shankar PR, Fields SK, Collins CL, Dick RW, Comstock RD.
Epidemiology of high school and collegiate football injuries in the
United States, 2005–2006. Am J Sports Med. 2007;35(8):1295–1303.
29. Yard EE, Collins CL, Dick RW, Comstock RD. An epidemiologic
comparison of high school and college wrestling injuries. Am J Sports
30. Fernandez WG, Yard EE, Comstock RD. Epidemiology of lower
extremity injuries among U.S. high school athletes. Acad Emerg Med.
31. United States Census Bureau. Census regions and divisions of the
United States. http://www.census.gov/geo/www/us_regdiv.pdf. Ac-
cessed February 15, 2007.
32. Larrain MV, Montenegro HJ, Mauas DM, Collazo CC, Pavon E.
Arthroscopic management of traumatic anterior shoulder instability
in collision athletes: analysis of 204 cases with a 4- to 9-year follow-up
and results with the suture anchor technique. Arthroscopy. 2006;
33. Agel J, Ransone J, Dick R, Oppliger R, Marshall SW. Descriptive
epidemiology of collegiate men’s wrestling injuries: National Colle-
giate Athletic Association Injury Surveillance System, 1988–1989
through 2003–2004. J Athl Train. 2007;42(2):303–310.
34. Hill JL, Humphries B, Weidner T, Newton RU. Female collegiate
windmill pitchers: influences to injury incidence. J Strength Cond Res.
35. Dick R, Ferrara MS, Agel J, et al. Descriptive epidemiology of
collegiate men’s football injuries: National Collegiate Athletic
Association Injury Surveillance System, 1988–1989 through 2003–
2004. J Athl Train. 2007;42(2):221–233.
36. Rechel JA, Yard EE, Comstock RD. An epidemiologic comparison
of high school sports injuries sustained in practice and competition.
J Athl Train. 2008;43(2):197–204.
37. Agel J, Palmieri-Smith RM, Dick R, Wojtys EM, Marshall SW.
Descriptive epidemiology of collegiate women’s volleyball injuries:
National Collegiate Athletic Association Injury Surveillance System,
1988–1989 through 2003–2004. J Athl Train. 2007;42(2):295–302.
John E. Bonza, MPH, contributed to analysis and interpretation of the data and drafting and final approval of the article. Sarah K. Fields,
JD, PhD, contributed to analysis and interpretation of the data and critical revision and final approval of the article. Ellen E. Yard, MPH,
contributed to acquisition of the data and critical revision and final approval of the article. R. Dawn Comstock, PhD, contributed to
conception and design, acquisition of the data, and critical revision and final approval of the article.
Address correspondence to Ellen E. Yard, MPH, Center for Injury Research and Policy, The Research Institute at Nationwide Children’s
Hospital, 700 Children’s Drive, Columbus, OH 43205. Address e-mail to Ellen.Yard@NationwideChildrens.org.
Journal of Athletic Training83