Module 11

278 Volume 42 • Number 2 • June 2007

Journal of Athletic Training 2007;42(2):278–285 � by the National Athletic Trainers’ Association, Inc www.journalofathletictraining.org

Descriptive Epidemiology of Collegiate Women’s Soccer Injuries: National Collegiate Athletic Association Injury Surveillance System, 1988–1989 Through 2002–2003 Randall Dick, MS, FACSM*; Margot Putukian, MD, FACSM†; Julie Agel, MA, ATC‡; Todd A. Evans, PhD, ATC§; Stephen W. Marshall, PhD��

*National Collegiate Athletic Association, Indianapolis, IN; †Princeton University, Princeton, NJ; ‡University of Minnesota, Minneapolis, MN; §University of Northern Iowa, Cedar Falls, IA; �University of North Carolina at Chapel Hill, Chapel Hill, NC

Objective: To review 15 years of National Collegiate Athletic Association (NCAA) injury surveillance data for women’s soccer and identify potential areas for injury prevention initiatives.

Background: The number of NCAA schools sponsoring women’s soccer has grown tremendously, from 271 in 1988– 1989 to 879 schools in 2002–2003. During that time, the NCAA Injury Surveillance System has collected game and practice in- jury data for women’s soccer across all 3 NCAA divisions.

Main Results: The rate of injury was more than 3 times high- er in games than in practices (16.44 versus 5.23 injuries per 1000 athlete-exposures, rate ratio � 3.2, 95% confidence in- terval � 3.1, 3.4, P � .01), and preseason practices had an injury rate that was more than 3 times greater than the rate for in-season practices (9.52 versus 2.91 injuries per 1000 athlete- exposures, rate ratio � 3.3, 95% confidence interval � 3.1, 3.5, P � .01). Approximately 70% of all game and practice injuries affected the lower extremities. Ankle ligament sprains (18.3%), knee internal derangements (15.9%), concussions (8.6%), and leg contusions (8.3%) accounted for a substantial portion of game injuries. Upper leg muscle-tendon strains (21.3%), ankle ligament sprains (15.3%), knee internal derangements (7.7%),

and pelvis and hip muscle strains (7.6%) represented most of the practice injuries. Injuries were categorized as attributable to player contact, ‘‘other contact’’ (eg, contact with the ball, ground, or other object), or no contact. Player-to-player contact accounted for more than half of all game injuries (approximately 54%) but less than 20% of all practice injuries. The majority of practice injuries involved noncontact injury mechanisms. Knee internal derangements, ankle ligament sprains, and concus- sions were the leading game injuries that resulted in 10 or more days of time lost as a result of injury.

Recommendations: Ankle ligament sprains, knee internal derangements, and concussions are common injuries in wom- en’s soccer. Research efforts have focused on knee injuries and concussions in soccer, and further epidemiologic data are needed to determine if preventive strategies will help to alter the incidence of these injuries. Furthermore, the specific nature of the player contact leading to concussions and lower extrem- ity injuries should be investigated. Preventive efforts should continue to focus on reducing knee injuries, ankle injuries, and concussions in women collegiate soccer players.

Key Words: athletic injuries, injury prevention, knee injuries, ankle injuries, concussions

T he National Collegiate Athletic Associate (NCAA) con- ducted its first women’s soccer championship in 1982. In the 1988–1989 academic year, 271 schools were

sponsoring varsity women’s soccer teams, with a total of ap- proximately 5976 participants. By 2002–2003, the number of varsity teams had increased 226% to 879, involving 19 871 participants.1 Participation growth during this time has oc- curred in all 3 NCAA divisions.

SAMPLING AND METHODS

Over the 15-year period studied, an average of 13.9% of schools sponsoring varsity women’s soccer programs partici- pated in annual NCAA Injury Surveillance System (ISS) data collection (Table 1). Women’s soccer data were not collected during the 2003–2004 year as a result of pilot testing for con- version to a Web-based system. The sampling process, data collection methods, injury and exposure definitions, inclusion

criteria, and data analysis methods are described in detail in the ‘‘Introduction and Methods’’ article in this special issue.2

RESULTS

Game and Practice Athlete-Exposures

The average annual numbers of games, practices, and ath- letes participating for each NCAA division, condensed over the study period, are shown in Table 2. The 3 divisions av- eraged a similar number of game and practice participants and a similar number of games played annually. Division I and Division II averaged a higher number of practices each year than Division III.

Injury Rate by Activity, Division, and Season

Game and practice injury rates over time combined across divisions, with 95% confidence intervals (CIs), are displayed

Journal of Athletic Training 279

Table 1. School Participation Frequency (in Total Numbers) by Year and National Collegiate Athletic Association (NCAA) Division, Women’s Soccer, 1988–1989 Through 2002–2003*

Academic Year

Division I Schools

Participating Sponsoring

Division II Schools

Participating Sponsoring

Division III Schools

Participating Sponsoring

All Divisions

Participating Sponsoring Percentage

1988–1989 14 72 4 43 21 155 39 271 14.4 1989–1990 11 75 6 44 23 175 40 294 13.6 1990–1991 14 82 11 51 26 185 51 318 16.0 1991–1992 22 91 10 60 30 199 62 350 17.7 1992–1993 20 103 9 69 31 215 60 387 15.5 1993–1994 23 131 7 79 24 236 54 446 12.1 1994–1995 30 154 13 97 36 264 79 515 15.3 1995–1996 31 189 15 127 45 315 91 631 14.4 1996–1997 35 217 16 146 42 331 93 695 13.4 1997–1998 38 233 17 154 38 337 93 724 12.8 1998–1999 24 251 15 177 46 362 8 5 790 10.8 1999–2000 43 260 19 182 41 369 103 811 12.7 2000–2001 35 274 17 199 34 378 86 851 10.1 2001–2002 33 280 25 201 44 387 102 868 11.8 2002–2003 56 288 25 199 77 392 158 879 18.0

Average 29 180 14 122 37 287 80 589 13.9

*‘‘Participating’’ refers to schools that provided appropriate data to the NCAA Injury Surveillance System; ‘‘Sponsoring’’ refers to the total number of schools offering the sport within the NCAA divisions.

Table 2. Average Annual Games, Practices, and Athletes Participating by National Collegiate Athletic Association Division, Women’s Soccer, 1988–1989 Through 2002–2003

Division Games Athletes

per Game Practices Athletes

per Practice

I 18 16 52 21 II 18 16 50 20 III 17 16 44 20

Figure 1. Injury rates and 95% confidence intervals per 1000 athlete-exposures by games, practices, and academic year, women’s soccer, 1988–1989 through 2002–2003 (n � 5373 game and 5836 practice injuries). Game time trend P � .59. Average annual change in game injury rate � 0.4% (95% confidence interval � �1.1, 1.9). Practice time trend P � .28. Average annual change in practice injury rate � �0.9% (95% confidence interval � �2.5, 0.7).

in Figure 1. Over the 15 years, the rate of injury was 3 times higher in a game than in a practice (16.4 versus 5.2 injuries per 1000 athlete exposures [A-Es], rate ratio � 3.2, 95% CI � 3.1, 3.4). A nonsignificant average annual increase in game (0.40%, P � .59) and nonsignificant average annual decrease in practice (�0.90%, P � .28) injury rates occurred over the

sample period. Based on visual inspection of Figure 1, injury rates appear to have decreased over the past few years.

The total number of games and practices and associated injury rates, condensed over years by division and season (pre- season, in season, and postseason), are presented in Table 3. Over the 15-year period, 5373 injuries from more than 20 000 games and 5836 injuries from more than 54 000 practices were reported. Practice injury rates were similar across all 3 divi- sions (P � .72), but game injury rates were higher in Division I than in Division III (P � .01). For games, the preseason injury rate was higher than that for the in season, and the in- season rate was higher than the postseason rate (preseason ver- sus regular season: 19.65 versus 16.56 injuries per 1000 A-Es, rate ratio � 1.19, 95% CI � 1.04, 1.36, P � .01; in season versus postseason: 16.56 versus 11.67 injuries per 1000 A-Es, rate ratio � 1.4, 95% CI � 1.22, 1.65, P � .01). For

280 Volume 42 • Number 2 • June 2007

Table 3. Games and Practices With Associated Injury Rates by National Collegiate Athletic Association Division and Season, Women’s Soccer, 1988–1989 Through 2002–2003*

Total No. of Games

Reported

Game Injury Rate per 1000

Athlete-Exposures

95% Confidence

Interval Total No. of

Practices Reported

Practice Injury Rate per 1000

Athlete-Exposures

95% Confidence

Interval

Division I

Preseason 263 24.04 19.48, 28.59 7495 9.1 8.63, 9.56 In season 6980 17.85 17.07, 18.63 13 619 3.04 2.84, 3.25 Postseason 369 13.99 11.00, 17.01 653 1.92 1.18, 2.66

Total Division I 7612 17.89 17.14, 18.64 21 767 5.2 5.00, 5.41

Division II

Preseason 140 21.62 15.50, 27.74 3541 9.69 8.97, 10.40 In season 3327 16.67 15.56, 17.78 6169 2.69 2.39, 2.98 Postseason 143 9.21 5.27, 13.15 276 1.47 0.45, 2.49

Total Division II 3610 16.48 15.43, 17.53 9986 5.25 4.93, 5.56

Division III

Preseason 266 14.18 10.65, 17.72 7424 9.88 9.39, 10.37 In season 8464 15.45 14.78, 16.11 14 636 2.88 2.69, 3.08 Postseason 399 10.41 7.90, 12.92 741 1.01 0.50, 1.52

Total Division III 9129 15.21 14.58, 15.84 22 801 5.25 5.04, 5.46

All Divisions

Preseason 3203 19.65 17.04, 22.23 21 242 9.52 9.21, 9.83 In season 16 252 16.56 16.10, 17.02 29 562 2.91 2.79, 3.04 Postseason 757 11.67 9.91, 13.43 1360 1.45 1.04, 1.85

Total 20 447 16.44 16.00, 16.88 54 750 5.23 5.09, 5.36

*Wald �2 statistics from negative binomial model: game injury rates differed among divisions (P � .01) and within season (P � .01). Practice injury rates did not differ among divisions (P � .72) but did differ within season (P � .01). Postseason sample sizes are much smaller (and have a higher variability) than preseason and in season sample sizes because only a small percentage of schools participated in the postseason tournaments in any sport and not all of those were a part of the Injury Surveillance System (ISS) sample. Numbers do not always sum to totals because of missing division or season information.

Table 4. Percentage of Game and Practice Injuries by Major Body Part, Women’s Soccer, 1988–1989 Through 2002–2003

Body Part Games Practices

Head/neck 13.8 3.9 Upper extremity 6.3 4.2 Trunk/back 8.4 13.2 Lower extremity 67.8 72.0 Other/system 3.7 6.7

practices, the preseason injury rate was significantly higher than that for the in season or postseason (preseason versus in season: 9.52 versus 2.91 injuries per 1000 A-Es, rate ratio � 3.27, 95% CI � 3.09, 3.45, P � .01; preseason versus post- season: 9.52 versus 1.45 injuries per 1000 A-Es, rate ratio � 6.57, 95% CI � 4.96, 8.71, P � .01).

Body Parts Injured Most Often and Specific Injuries

The frequency of injury to 5 general body parts (head/neck, upper extremity, trunk/back, lower extremity, and other/sys- tem) for games and practices, with years and divisions com- bined, is shown in Table 4. Approximately 70% of all game and practice injuries were to the lower extremity. Head and neck injuries accounted for another 13.8% of game injuries but only 3.9% of practice injuries.

The most common body part and injury type combinations for games and practices with years and divisions combined are displayed in Table 5. All injuries that accounted for at least 1% of reported injuries over the 15-year sampling period were

included. In games, ankle ligament sprains (18.3%), knee in- ternal derangements (15.9%), and concussions (8.6%) account- ed for the majority of injuries. Contusions to the upper and lower leg and upper leg muscle-tendon strains also were sig- nificant categories. In practices, upper leg muscle-tendon strains (21.3%), ankle ligament sprains (15.3%), knee internal derangements (7.7%), and pelvis and hip muscle strains (7.6%) represented more than 50% of all reported injuries, with con- cussions accounting for only 2.2%. A participant was almost 12 times more likely to receive a concussion in a game than in a practice (1.42 versus 0.12 injuries per 1000 A-Es, rate ratio � 11.8, 95% CI � 11.4, 12.3), more than 6 times more likely to sustain a knee internal derangement in a game than in a practice (2.61 versus 0.40 per 1000 A-Es, rate ratio � 6.5, 95% CI � 6.3, 6.8), almost 4 times as likely to sustain an ankle ligament sprain in a game than in a practice (3.01 versus 0.80 per 1000 A-Es, rate ratio � 3.8, 95% CI � 3.6, 3.9), and equally likely to sustain an upper leg muscle-tendon strain in a game or a practice (1.14 versus 1.11 per 1000 A-Es, rate ratio � 1.0, 95% CI � 1.0, 1.1).

Mechanism of Injury

The 3 primary injury mechanisms—player contact, other contact (eg, contact with balls, goals, or the ground), and non- contact mechanisms—in games and practices, with division and years combined, are presented in Figure 2. Most game injuries (approximately 54%) resulted from player contact. The remaining game injuries were equally distributed between noncontact mechanisms and other contact mechanisms (ap-

Journal of Athletic Training 281

Table 5. Most Common Game and Practice Injuries, Women’s Soccer, 1988–1989 Through 2002–2003*

Body Part Injury Type Frequency Percentage of

Injuries

Injury Rate per 1000

Athlete-Exposures 95% Confidence

Interval

Games

Ankle Ligament sprain 984 18.3 3.01 2.82, 3.20 Knee Internal derangement 852 15.9 2.61 2.43, 2.78 Head Concussion 463 8.6 1.42 1.29, 1.55 Upper leg Muscle-tendon strain 374 7.0 1.14 1.03, 1.26 Lower leg Contusion 246 4.6 0.75 0.66, 0.85 Upper leg Contusion 198 3.7 0.61 0.52, 0.69 Unspecified† Unspecified 139 2.6 0.43 0.35, 0.50 Pelvis, hip Muscle-tendon strain 120 2.2 0.37 0.30, 0.43 Knee Contusion 91 1.7 0.28 0.22, 0.34 Patella Patella or patella tendon injury 91 1.7 0.28 0.22, 0.34 Foot Contusion 90 1.7 0.28 0.22, 0.33 Lower leg Muscle-tendon strain 69 1.3 0.21 0.16, 0.26 Lower back Muscle-tendon strain 68 1.3 0.21 0.16, 0.26 Ankle Contusion 59 1.1 0.18 0.13, 0.23 Nose Fracture 57 1.1 0.17 0.13, 0.22 Pelvis, hip Contusion 55 1.0 0.17 0.12, 0.21 Foot Ligament sprain 53 1.0 0.16 0.12, 0.21

Practices

Upper leg Muscle-tendon strain 1243 21.3 1.11 1.05, 1.18 Ankle Ligament sprain 892 15.3 0.80 0.75, 0.85 Knee Internal derangement 449 7.7 0.40 0.36, 0.44 Pelvis, hip Muscle-tendon strain 444 7.6 0.40 0.36, 0.43 Unspecified† Unspecified 271 4.6 0.24 0.21, 0.27 Patella Patella or patella tendon injury 166 2.8 0.15 0.13, 0.17 Head Concussion 130 2.2 0.12 0.10, 0.14 Lower leg Muscle-tendon strain 129 2.2 0.12 0.10, 0.14 Lower back Muscle-tendon strain 94 1.6 0.08 0.07, 0.10 Knee Tendinitis 91 1.6 0.08 0.06, 0.10 Heel/Achilles tendon Tendinitis 83 1.4 0.07 0.06, 0.09 General body Heat illness 70 1.2 0.06 0.05, 0.08 Lower leg Inflammation 70 1.2 0.06 0.05, 0.08 Lower leg Contusion 67 1.2 0.06 0.05, 0.07 Lower leg Stress fracture 67 1.2 0.06 0.05, 0.07

*Only injuries that accounted for at least 1% of all injuries are included. †‘‘Unspecified’’ indicates injuries that could not be grouped into existing categories but that were believed to constitute reportable injuries.

Figure 2. Game and practice injury mechanisms, all injuries, wom- en’s soccer, 1988–1989 through 2002–2003 (n � 5373 game injuries and n � 5836 practice injuries). ‘‘Other contact’’ refers to contact with items such as balls, goals, or the ground. Injury mechanism was unavailable for 2% of game injuries and 5% of practice inju- ries.

proximately 22% each). Noncontact injury mechanisms were the primary mechanism for injuries sustained during practices (56%).

Severe Injuries: 10� Days of Activity Time Loss

The most common injuries that resulted in at least 10 con- secutive days of restricted or total loss of participation and their primary injury mechanisms, combined across divisions and years, are shown in Table 6. Time loss of 10� days was, for this analysis, considered a measure of severe injury. Ap- proximately 22% of game and 17% of practice injuries re- stricted participation for at least 10 days. In both games and practices, knee internal derangements accounted for the high- est percentage of these more severe injuries (44.1% and 25.5%, respectively).

Ankle ligament sprains accounted for similar percentages of game (13.3%) and practice (13.8%) 10� day time-loss in- juries. Concussions represented 6.0% of severe game injuries. The most frequent severe game injuries were all associated with player contact, whereas the top severe practice injuries were associated with noncontact injury mechanisms.

282 Volume 42 • Number 2 • June 2007

Table 6. Most Common Game and Practice Injuries Resulting in 10� Days of Activity Time Loss, Women’s Soccer, 1988–1989 Through 2002–2003

Body Part Injury Type Frequency Percentage of Severe Injuries

Most Common Injury Mechanism

Games (21.8% of all injuries required 10� days of time loss)

Knee Internal derangement 518 44.1 Player contact Ankle Ligament sprain 156 13.3 Player contact Head Concussion 70 6.0 Player contact Other 431 36.7 Total 1175

Practices (16.5% of all injuries required 10� days of time loss)

Knee Internal derangement 245 25.5 No contact Ankle Ligament sprain 133 13.8 No contact Upper leg Muscle-tendon strain 92 9.6 No contact Other 491 51.1 Total 961

Figure 3. Game concussion injury mechanisms, women’s soccer, 1988–1989 through 2002–2003 (n � 463).

Figure 4. Game and practice anterior cruciate ligament injury mechanisms, women’s soccer, 1988–1989 through 2002–2003 (n � 298).

Game Injuries

The mechanisms of game concussions over all years are displayed in Figure 3. A total of 67.7% of reported concus- sions were due to player contact; another 18.3% were asso- ciated with contact with the ball, and 13.4% were associated with contact with the playing surface. Less than 1% were as- sociated with contacting the goal.

The mechanisms of anterior cruciate ligament (ACL) inju- ries over all years are presented in Figure 4. These injuries accounted for 6% of game injuries and 2% of practice injuries. Most game (53%) and practice (65%) ACL injuries resulted from noncontact mechanisms.

Regarding activity at the time of injury, across all types of game injuries, approximately 13% were associated with either attempting or receiving a slide tackle (data not shown).

COMMENTARY

Despite tremendous growth in participation, the injury rate and injury profile in women’s collegiate soccer players have remained relatively stable over the past 15 years, with a non- significant increase in game injury rates and a nonsignificant

Journal of Athletic Training 283

decrease in practice injury rates over the sample period. Al- though it would be difficult to confirm, we speculate that the recent emphasis on preventive strategies and programs that include flexibility, plyometric, strength, and neuromuscular training specifically designed for reducing ACL injuries and ankle sprains may have contributed to the fact that injury rates have not risen, despite an increase in the intensity of compe- tition over the 15-year period. The game injury rate was just over 3 times higher than that observed during practice, and this relationship has also remained stable over time. This re- lationship is also consistent with recent reports of adolescent soccer players indicating a predominance of lower extremity injuries that are, for the most part, minor.3–5

For a variety of reasons, however, caution should be used when comparing this current NCAA ISS data with previous descriptive injury studies. Often the injury definitions and methods were different among studies. Several authors did not use a time-loss definition for injury, and many did not incor- porate A-Es as the denominator. Furthermore, data collection for previous studies was not performed by certified athletic trainers, and the data entry intervals were not consistent with those used in this current NCAA ISS report. The NCAA ISS system is unique in that it relies on certified athletic trainers to collect data, and data entry occurs in a timely fashion, as opposed to investigations by other researchers, who may have relied upon nonmedical personnel for providing data such as that included in insurance claims or coaches’ reports.

Despite these limitations of previous studies, the current in- jury distribution is similar to that reported at other levels of soccer play, demonstrating that more than two thirds of all injuries occurred in the lower extremities. Ankle sprains were the most common game injury, and knee internal derange- ments resulted in the greatest time loss,3,4,6,7 as demonstrated in both outdoor and indoor soccer games8,9 and at all levels of competition.3,4,7

For games, the regular-season injury rate was significantly higher than that for the postseason, whereas for practices, the preseason injury rate was significantly higher than that for the regular season or postseason. Some speculate that increased ability is associated with a higher incidence of injury, but these current results indicate no difference, at least in practice injury rates, among Divisions I through III. Furthermore, the as- sumption that Division I athletes are more skilled than those in Divisions II or III has not been established.

The most common injuries in games were ankle ligament sprains, knee internal derangements, and concussions. These results are not surprising and underscore the need for preven- tion of lower extremity injuries and concussions. Soccer play- ers are often resistant to using ankle braces or to having their ankles taped for activity, but the high incidence of ankle lig- ament sprains emphasizes the importance of preventive pro- grams to identify athletes with injuries that may not have been properly rehabilitated or for whom taping or bracing might be appropriate. These programs have been successful in decreas- ing injuries in soccer players.10

For practices, the most common injuries were upper leg muscle-tendon strains, ankle ligament sprains, and knee inter- nal derangements, again underscoring the need for future re- search to determine methods to prevent these injuries. Con- cussions and other facial injuries did not occur commonly in practices.

These data also highlight the frequency and effect of knee ligament injuries in female soccer players. These injuries re-

mained mostly noncontact in both practices and games. This game ACL injury mechanism is consistent with that recently reported by Fauno and Wulff Jakobsen,11 who noted that for 113 confirmed ACL game injuries, the mechanism was pre- dominantly noncontact.

The prominence of ACL injuries in women’s sports has driven research initiatives aimed at identifying risk factors, which could help us to develop preventive measures.12–17 In 1999, Hewett et al18 provided neuromuscular training to soc- cer, basketball, and volleyball players for sessions of 60 to 90 minutes, administered 3 times per week for 6 weeks, and dem- onstrated a 72% decrease in noncontact ACL injuries. This type of injury risk information has led many NCAA schools to incorporate preventive neuromuscular control exercises and agility tasks during practices and conditioning. These pro- grams all have strength, flexibility, agility, aerobic condition- ing, plyometrics, and risk awareness training in common.16

Preliminary reports do support the effectiveness of such neu- romuscular training programs in preventing ACL injury.12,14,17

Mandelbaum et al17 demonstrated that in 14-year-old to 18- year-old soccer players, an intervention program (Prevent In- jury and Enhance Performance Program) emphasizing propri- oception and neuromuscular training was associated with a 74% reduction in ACL tears over the subsequent 2 years. The intervention program included 20 minutes of soccer-specific agility drills, plyometrics, lower extremity and trunk stretch- ing, strengthening exercises, and general warm-up activities. However, additional research using randomized, controlled de- signs is necessary to evaluate the effectiveness of these types of programs in reducing the rate of ACL injuries in female collegiate athletes.

Although knee internal derangement injuries resulted in the greatest time loss per incident, ankle ligament sprains re- mained the most common injury seen in practices and games. Ankle ligament sprains are typically considered less severe than knee internal derangements, but they accounted for a con- siderable portion of time-loss injuries. Significant research has focused on the effectiveness of preseason screening for ankle laxity and/or inadequate rehabilitation from prior ankle injuries in preventing future ankle sprains in soccer.10,19 Unfortunately, many of these injuries are recurrent and occur even when pro- tective strapping is in place.20 Neuromuscular training strate- gies, however, do offer promise in reducing ankle injury and reinjury. McGuine and Keene21 found that a combined pre- season and in-season balance training program significantly reduced the rates of both first-time and recurrent ankle sprains. Given the frequency and severity of ankle injuries in women’s collegiate soccer players, athletic trainers should focus on the implementation and the effect of preventive measures in lim- iting the occurrence and recurrence of ankle sprains.

Concussions are another frequent and important injury in collegiate female soccer players, accounting for 8.6% of game injuries overall and 6.0% of game injuries resulting in more than 10 days of time loss. The primary mechanism of head injury in this study, player contact, was also identified as such by previous authors investigating collegiate soccer.22,23 Fuller et al23 studied videotapes of international men’s and women’s soccer games (19 802 player-hours of match-exposures) and evaluated the mechanisms of head and neck injuries. Concus- sions accounted for 11% of the injuries, and the most common mechanisms involved (sometimes overlapping) challenges while both athletes were in the air (55%) and the use of the upper extremity (33%) or the head (30%). Of all player ac-

284 Volume 42 • Number 2 • June 2007

tions, unfair use of the upper extremity was most commonly associated with injury. Similarly, Anderson et al24 reported that heading duels accounted for 58% of head injuries, with upper extremity contact accounting for 41% and contact with the opponent’s head accounting for 32% (again, the types of contact can overlap). Although player-to-player contact has been consistently identified as a head injury mechanism, con- tact with the ball has not. Fuller et al23 found that only 1 cervical strain of 248 head and neck injuries could be attri- buted to purposeful heading of the ball. Anderson et al24 did not identify heading the ball as a mechanism for head injury. These results support those of previous researchers, who have failed to identify purposeful heading as a primary cause of con- cussion.22,25–28

Specific circumstances and player actions have been rec- ognized as risk factors. The risk of injury is considered to be highest in the first and last 15 minutes of play, when players are fighting for possession of the ball in the attacking and defending areas close to the goal.29 Players are at an increased risk for injury when they receive or deliver a tackle or charge and when they are involved in play that is unfair or ille- gal.23,29–32 Anderson et al32 reported that 20% of head injuries due to elbow-to-head contact were related to illegal, purpose- ful use of the upper extremity during an aerial heading chal- lenge. Fauno and Wulff Jakobsen11 noted that 11% of ACL injuries were associated with the administration of a red or yellow card to the opponent. Therefore, as in other contact and collision sports, proper enforcement of the rules by officials is likely important in decreasing the risk for injury.

Player contact appeared to account for the majority of game injuries, whereas injuries from noncontact mechanisms (no di- rect contact to the injured body part) were predominant in practices. This may be because overuse injuries are more likely to be reported by players during practices and less likely to be reported during games.

Muscle-tendon strain injuries are common in soccer because of the nature of the sport, which involves running, sprinting, and sport-specific skills that often require the player to kick or strike the ball with full force. Strains involving the lower extremity predominate, again because of the acceleration and deceleration forces required during running and cutting and the overuse of these muscles with soccer-specific play. Many of these muscle strains can be addressed with better stretching and other injury prevention measures.

Given the contact nature of soccer, contusions are also com- mon, frequently involving the lower extremity. Large muscle contusions involving the quadriceps are typical.

For both games and practices, fractures are relatively un- common in women’s soccer players. When they do occur, they are more likely during games and are also more likely to affect the upper extremity. The mechanism of these injuries, although not reported, is most likely due to falling on an outstretched hand (hand, wrist, and finger injuries) or landing on the shoul- der (clavicle fracture). Lower leg fractures are uncommon and most often occur as a result of trauma to the lower leg. Shin guards may be useful in protecting against lower leg injuries and fractures.

Prior injury has also been associated with an increased risk of injury.11,33–35 This factor emphasizes the need to evaluate athletes before the competitive season to identify those at risk based on a previous injury history, specifically focusing on injuries that have not been effectively rehabilitated. Hagglund et al33 found a 2-fold to 3-fold increase in injury in soccer

players with a history of hamstring strain, groin injury, or knee joint trauma, with the injury occurring in the previously in- jured site. Injury prevention strategies specific to hamstring injuries,36 ankle sprains,19,20,37,38 and ACL injuries14,17,18,39

are all promising areas of further research. Inadequate reha- bilitation and preexisting ligamentous laxity from prior injuries are thought to be risk factors for knee and ankle injuries,19,38

underscoring the importance of detecting these problems in preseason evaluations. Athletic trainers can play a significant role in screening for injury history, preexisting injuries, and injuries that have not been appropriately rehabilitated.

In summary, most of the injuries in women’s soccer affected the lower extremities, with ankle ligament sprains and knee internal derangements representing the most common game injuries. Furthermore, concussions continue to be a concern during games. Despite increased focus and research addressing knee internal derangements and concussions in women’s sports, evidence to indicate that preventive measures have re- duced the risk of these injuries is limited. The lack of a sig- nificant upswing in injury rates over the past few years, despite the escalating intensity of competition, may reflect the benefits of injury prevention strategies. However, additional research is needed to evaluate mechanisms of concussion and knee in- juries and the preventive effect of current programs, such as those emphasizing neuromuscular control or cognitive testing, on injury prevention.

DISCLAIMER

The conclusions in the Commentary section of this article are those of the Commentary authors and do not necessarily represent the views of the National Collegiate Athletic Asso- ciation.

REFERENCES

1. National Collegiate Athletic Association. 1981-82–2004-05 NCAA Sports Sponsorship and Participation Rates Report. Indianapolis, IN: National Collegiate Athletic Association; 2006.

2. Dick R, Agel J, Marshall SW. National Collegiate Athletic Association Injury Surveillance System commentaries: introduction and methods. J Athl Train. 2007;42:173–182.

3. Emery CA, Meeuwisse WH, Hartmann SE. Evaluation of risk factors for injury in adolescent soccer: implementation and validation of an injury surveillance system. Am J Sports Med. 2005;33:1882–1891.

4. Soderman K, Adolphson J, Lorentzon R, Alfredson H. Injuries in ado- lescent female players in European football: a prospective study over one outdoor soccer season. Scand J Med Sci Sports. 2001;11:299–304.

5. Le Gall F, Carling C, Reilly T, Vandewalle H, Church J, Rochcongar P. Incidence of injuries in elite French youth soccer players: a 10-season study. Am J Sports Med. 2006;34:928–938.

6. Elias SR. 10 year trend in USA Cup soccer injuries: 1988–1997. Med Sci Sports Exerc. 2001;33:359–367.

7. Peterson L, Junge A, Chomiak J, Graf-Baumann T, Dvorak J. Incidence of football injuries and complaints in different age groups and skill-level groups. Am J Sports Med. 2000;28:S51–S57.

8. Putukian M, Knowles WK, Swere S, Castle NG. Injuries in indoor soccer: The Lake Placid Dawn to Dark Soccer Tournament. Am J Sports Med. 1996;24:317–322.

9. Lindenfeld TN, Schmitt DJ, Hendy MP, Mangine RE, Noyes FR. Inci- dence of injury in indoor soccer. Am J Sports Med. 1994;22:364–372.

10. Ekstrand J, Gillquist J. Prevention of sport injuries in football players. Int J Sports Med. 1984;5(suppl):140–144.

11. Fauno P, Wulff Jakobsen B. Mechanism of anterior cruciate ligament in- juries in soccer. Int J Sports Med. 2006;27:75–79.

12. Hewett TE, Myer GD, Ford KR, Heidt RS, Colosimo AJ, Succop P. Bio-

Journal of Athletic Training 285

mechanical measures of neuromuscular control and valgus loading of the knee predict anterior cruciate ligament injury risk in female athletes. Am J Sports Med. 2005;33:492–501.

13. Griffin LY, Albohm MJ, Arendt EA, et al. Understanding and preventing noncontact anterior cruciate ligament injuries: a review of the Hunt Valley II meeting, January 2005. Am J Sports Med. 2006;34:1512–1532.

14. Myklebust G, Engebretsen L, Braekken IH, Skjolberg A, Olsen OE, Bahr R. Prevention of anterior cruciate ligament injuries in female team hand- ball players: a prospective intervention study over three seasons. Int J Sports Med. 2003;13:71–78.

15. Hewett TE, Myer GD, Ford KR. Anterior cruciate ligament injuries in female athletes, part 1: mechanisms and risk factors. Am J Sports Med. 2006;34:299–311.

16. Hewett TE, Ford KR, Myer GD. Anterior cruciate ligament injuries in female athletes, part 2: a meta-analysis of neuromuscular interventions aimed at injury prevention. Am J Sports Med. 2006;34:490–498.

17. Mandelbaum BR, Silvers HJ, Watanabe DS, et al. Effectiveness of a neu- romuscular and proprioceptive training program in preventing anterior cruciate ligament injuries in female athletes: 2-year follow-up. Am J Sports Med. 2005;33:1003–1010.

18. Hewett TE, Lindenfeld TN, Riccobene JV, Noyes FR. The effect of neu- romuscular training on the incidence of knee injury in female athletes: a prospective study. Am J Sports Med. 1999;27:699–706.

19. Surve I, Schwellnus MP, Noakes T, et al. A fivefold reduction in the incidence of recurrent in ankle sprains in soccer players using the sport- stirrup orthosis. Am J Sports Med. 1994;22:601–606.

20. Woods C, Hawkins R, Hulse M, Hodson A. The Football Association Medical Research Programme: an audit of injuries in professional foot- ball. An analysis of ankle sprains. Br J Sports Med. 2003;37:233–238.

21. McGuine TA, Keene JS. The effect of a balance training program on the risk of ankle injury in high school athletes. Am J Sports Med. 2006;34: 1103–1111.

22. Boden BP, Kirkendall DT, Garrett WE Jr. Concussion incidence in elite college soccer players. Am J Sports Med. 1998;26:238–241.

23. Fuller CW, Junge A, Dvorak J. A six year prospective study of the in- cidence and causes of head and neck injuries in international football. Br J Sports Med. 2005;39(suppl 1):3–9.

24. Anderson TE, Amason A, Engebretsen L, Bahr R. Mechanisms of head injuries in elite football. Br J Sports Med. 2004;38:690–696.

25. Putukian M, Echemendia RJ, Mackin S. The acute neuropsychological effects of heading in soccer: a pilot study. Clin J Sport Med. 2000;10: 104–109.

26. Schmitt DM, Hertel J, Evans TA, Olmsted LC, Putukian M. Effect of an acute bout of soccer heading on postural control and self reported symp- toms of concussion. Int J Sports Med. 2004;25:326–331.

27. Straume-Naesheim TM, Anderson TE, Dvorak J, Bahr R. Effects of head- ing exposure and previous concussion on neuropsychological perfor- mance among Norwegian elite footballers. Br J Sports Med. 2005;39:70– 77.

28. Broglio SP, Guskiewicz KM, Sell TC, Lephart SM. No acute changes in postural control after soccer heading. Br J Sports Med. 2004;38:561–567.

29. Rahnama N, Reilly T, Lees A. Injury risk associated with playing actions during competitive soccer. Br J Sports Med. 2002;36:354–359.

30. Fuller CW, Junge A, Dvorak J. An assessment of football referees’ de- cisions in incidents leading to player injuries. Am J Sports Med. 2004; 32(suppl 1):S17–S22.

31. Fuller CW, Smith GL, Junge A, Dvorak J. The influence of tackle param- eters on the propensity for injury in international football. Am J Sports Med. 2004;32(suppl 1):S43–S53.

32. Anderson TE, Engebretsen L, Bahr R. Rule violations as a cause of in- juries in male Norwegian professional football: are the referees doing their job? Am J Sports Med. 2004;32(suppl 1):S62–S68.

33. Hagglund M, Walden M, Ekstrand J. Previous injury as a risk factor for injury in elite football: a prospective study over two consecutive seasons. Br J Sports Med. 2006;40:767–772.

34. Walden M, Hagglund M, Ekstrand J. High risk of new knee injury in elite footballers with previous anterior cruciate ligament injury. Br J Sports Med. 2006;40:158–162.

35. Dvorak J, Junge A, Chomiak J, et al. Risk factor analysis for injuries in football players: possibilities for a prevention program. Am J Sports Med. 2000;28(suppl 5):S69–S74.

36. Petersen J, Holmich P. Evidence based prevention of hamstring injuries in sport. Br J Sports Med. 2005;39:319–323.

37. Murphy DF, Connolly DA, Beynnon D. Risk factors for lower extremity injury: a review of the literature. Br J Sports Med. 2003;37:13–29.

38. Caraffa A, Cerulli G, Projetti M, Aisa G, Rizzo A. Prevention of anterior cruciate ligament injuries in soccer: a prospective controlled study of proprioceptive training. Knee Surg Sports Traumatol Arthrosc. 1996;4: 19–21.

39. Ekstrand J, Gillquist J, Moller M, Oberg B, Liljedahl SO. Incidence of soccer injuries and their relation to training and team success. Am J Sports Med. 1983;11:63–67.

Randall Dick, MS, FACSM, contributed to conception and design; analysis and interpretation of the data; and drafting, critical revision, and final approval of the article. Margot Putukian, MD, FACSM, contributed to analysis and interpretation of the data and drafting, critical revision, and final approval of the article. Julie Agel, MA, ATC; Todd A. Evans, PhD, ATC; and Stephen W. Marshall, PhD, contributed to conception and design; analysis and interpretation of the data; and drafting, critical revision, and final approval of the article. Address correspondence to Margot Putukian, MD, FACSM, Princeton University, McCosh Health Center, Princeton, NJ 08544. Address e- mail to [email protected].