Use of protective equipment is an important sports injury prevention strategy, yet use of protective equipment by high school athletes has seldom been studied. The authors analyzed data from a 3-year (1996–1999), stratified, two-stage cluster sample of athletes from 12 organized sports in 100 North Carolina high schools (n = 19,728 athlete-seasons). Information on each athlete's use of protective equipment and prior injury was collected during the preseason. Prospective information on injuries and weekly participation in games and practices was collected during the playing season. Use of lower extremity discretionary protective equipment tended to decrease the overall rate of lower extremity injury (rate ratio (RR) = 0.91, 95% confidence interval (CI): 0.72, 1.15). However, this slight protective effect was entirely due to kneepad use (for knee injury, RR = 0.44, 95% CI: 0.27, 0.74).  Knee brace use and ankle brace use were associated with increased rates of knee injury (RR = 1.61, 95% CI: 1.08, 2.41) and ankle injury (RR = 1.74, 95% CI: 1.11, 2.72), respectively. This could be due to slippage of the brace during use, increased fatigue due to the energy cost of wearing a brace, or bias in the study. Further investigation into the effects of brace use is warranted.
Youth sports injury has emerged as a public health problem in the last three decades, with detrimental effects on the health and well-being of young athletes and enormous economic costs to society (1–9). Sports and recreational activities are widely promoted as part of a healthy lifestyle for young people, but the physical and psychological benefits gained from participating in sports may be diminished by injuries (10–14).
Approximately two thirds of youth sports injuries occur in organized sports, and such injuries predominantly affect the lower extremities (15–20). Each year, approximately seven million high school students participate in organized sports (21). It is estimated that in an average year, 41–61 percent of football players, 40–46 percent of wrestlers and gymnasts, and 31–37 percent of basketball players sustain an injury while participating in organized high school sports (1, 22).
In many sports, particularly sports with full-body contact such as football, protective equipment is an integral component of the game and its use is required by national and state sports associations. In addition, many high school athletes use optional protective equipment that is not mandated by sports rules (though a given coach may require its use by his/her players). This discretionary use of protective equipment was the exposure examined in this study.
Although many high school athletes use discretionary protective equipment in an effort to prevent sports injuries, there is continuing debate about whether to recommend the use of certain types of protective equipment and, if so, what would constitute appropriate recommendations (23–28). Most sports injury studies to date have addressed the clinical aspects of injuries rather than prevention strategies (29–31). Very few studies have examined the use of discretionary protective equipment to prevent sports injury.  Prior research either has been limited to a specific piece of equipment or has focused on a particular sport (e.g., use of a knee brace in football or a mouth guard in basketball) and often has not distinguished whether the protective equipment studied was mandatory or discretionary (27, 32–34). The populations studied have often involved elite athletes, resulting in findings that may not be applicable to youth populations (35–38). Injury severity has seldom been reported or analyzed (17, 39).
The purpose of this study was to determine the relation between use of lower extremity discretionary protective equipment and the rate and severity of lower extremity injury among high school athletes during their participation in organized sports.
MATERIALS AND METHODS
Data and study design
In this study, we utilized data from the North Carolina High School Athletic Injury Study (1996–1999), a 3-year prospective cohort study of a stratified, two-stage cluster sample of North Carolina high school athletes. The study design involved first assigning high schools to 50 strata based on school size and region. Two schools were then randomly selected from each stratum. Second, six team sports in each study school were selected using systematic sampling. A list of existing sport programs in selected schools at the start of the 1996–1997 school year was sorted by season and sport to ensure that the sample spanned all seasons and included both girls' and boys' teams. Finally, all athletes on each selected team were included in the sample as study athletes. Each selected team was followed for 3 years. A detailed description of the study design and methods has been published elsewhere (40).
Twelve varsity sports were studied, with six male sports and six female sports. These included boys' and girls' soccer, track, and basketball; boys' baseball, wrestling, and football; and girls' softball, volleyball, and cheerleading. Four questionnaires were used in data collection: the Athlete's Demographic Form and the Coach's Form, which were completed by self-report prior to each season, and the Weekly Exposure Form and the Injury Report Form, which were administered during the season by trained data collectors, who were either athletic directors or athletic trainers employed by the school.
In this study, a lower extremity injury was defined as any new injury sustained between the hip and the toes that occurred in an organized sport and required medical attention or restricted participation on the day after the injury. Information on injury was collected at the time the injury occurred (40, 41).
The rate of lower extremity injury was one of two outcome variables in this study. The injury rate was calculated as the number of incident lower extremity injuries in a season divided by the total number of athlete-exposures in that season multiplied by 100,000. In this study, attending one coach-directed session of either a game or practice was defined as one athlete-exposure (40).
The severity of lower extremity injury, the other outcome variable in this study, was defined as the number of days lost from sports participation due to an incident lower extremity injury (39, 42). Lower extremity injury severity was evaluated for each injury and measured at four levels: “no time lost,” if an athlete lost no time; “minor injury,” if an athlete lost less than 1 week of participation time; “moderate injury,” if an athlete lost 1–3 weeks; and “serious injury,” if an athlete lost more than 3 weeks (43, 44). The analysis of injury severity included only those athletes who sustained lower extremity injuries during a given season.
Use of lower extremity discretionary protective equipment, the main exposure variable in this study, was defined as any self-reported usual use of lower extremity protective equipment not required by sports rules (45). For example, rules mandate the use of kneepads in football and shin guards in soccer; therefore, using such equipment in those sports was not classified as use of lower extremity discretionary protective equipment in this study.
We assessed use of lower extremity discretionary protective equipment during the preseason by asking athletes, “What protective equipment do you usually use?”  The athletes participating in a specific sport were asked to select the protective equipment they used from a checklist of items. The checklist varied by sport and could include the following items: helmet, headgear, face mask, mouth guard, shoulder pads, elbow brace, wrist guard, hip pads, kneepads, shin guards, knee brace, ankle brace, pads, and other. We manually reviewed the written-in responses in the “pads” and “other” categories to determine use of discretionary protective equipment. Because rules vary across sports, the same piece of protective equipment may be required in one sport yet optional in another. We determined whether athletes' use of a given piece of protective equipment was discretionary or mandatory based on the rules governing mandatory protective equipment use in each sport.
We limited discretionary protective equipment to the lower extremities because they are the most commonly injured body parts among high school athletes (15, 20). Use of lower extremity discretionary protective equipment was coded dichotomously, with “yes” representing self-reported usual use of any piece of lower extremity protective equipment that was not mandated by the rules across all sports studied.  The four types of lower extremity discretionary protective equipment most frequently used by high school athletes in this study were kneepads, shin guards, knee brace(s), and ankle brace(s). However, the subanalyses on use of specific types of lower extremity discretionary protective equipment were limited to kneepads, knee braces, and ankle braces because of small counts for nonmandatory use of shin guards.
A history of lower extremity injury, a covariate in this study, was measured during the preseason by asking each athlete whether he or she had previously sustained any injuries. The response categories were presented as a checklist specifying concussion, heat stroke, fracture, shoulder injury, elbow injury, wrist injury, knee injury, ankle injury, and other. Athletes who checked the “other” category were prompted to indicate up to three other injuries; these responses were manually reviewed and classified. In the case of athletes who remained in the study for more than 1 year, we updated the injury history variable to reflect the athletes' known prior injuries. Only athletes with a history of lower extremity injury were classified as having a history of injury.
We included four demographic variables in the analysis: sex (male or female), grade (ninth, tenth, eleventh, or twelfth), type of sport (full-contact, limited-contact, or noncontact), and whether the athlete had played multiple sports in the past (yes or no) (45). In this study, we categorized football and wrestling as full-contact sports, basketball, soccer, baseball, and softball as limited-contact sports, and track, volleyball, and cheerleading as noncontact sports, based on the amount of body contact the rules allow an athlete to have with his or her opponent (46).
We conducted separate analyses for the two outcome variables, injury rate and injury severity. To determine the rate of lower extremity injury, we performed descriptive analyses to characterize the frequency and rate per 100,000 athlete-exposures of lower extremity injury, knee injury, and ankle injury sustained during the sports season. We used Poisson regression to determine the effect of use of discretionary protective equipment on the prospective lower extremity injury rate. We modeled the rates of lower extremity injury sustained in games, in practices, and overall, taking into account game injuries, practice injuries, and all injuries, respectively, and adjusting denominators (games or practices) as appropriate. We excluded injuries that occurred in settings other than games or team practices (e.g., personal workouts) in the analysis because of the absence of time-at-risk (rate denominator) measurements for these injuries in this study.
We calculated unadjusted and adjusted lower extremity injury rate ratios from the Poisson regression models with no use of discretionary protective equipment as a referent. The demographic variables included in the adjusted analysis were sex, grade, past participation in multiple sports, and type of sport (45).
Athletes who have experienced a previous injury appear to be at increased risk of reinjury and more motivated to protect themselves by using discretionary protective equipment (37, 47). We performed subgroup analyses to compare the effect of use of discretionary protective equipment in participants with and without a history of lower extremity injury. Since most reported lower extremity injuries in this study were knee or ankle injuries, we conducted further analyses to examine the effects of knee brace use on knee injuries, kneepad use on knee injuries, and ankle brace use on ankle injuries.
To examine injury severity as an outcome, we limited the scope of the analysis to athletes injured in a given season, characterizing the severity of lower extremity injury among athletes who sustained lower extremity injuries. We used logistic regression to predict the effect of use of discretionary protective equipment on the probability of serious injury (>3 weeks lost) versus nonserious injury (≤3 weeks lost) given an occurrence of injury. The model was adjusted for athletes' demographic characteristics. Odds ratios were estimated with no discretionary protective equipment use as a referent (48).
We used SAS-Callable SUDAAN 8.0 computer software for all statistical analyses to account for the stratified two-stage cluster sampling design and for within-subject correlation (49). Data were weighted to account for the sampling design and for nonresponse.
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A total of 19,728 athlete-seasons and 1,104,354 athlete-exposures were included in the data analysis. The demographic characteristics of the study population and their use of lower extremity discretionary protective equipment are presented in table 1.
Of a total of 2,698 reported injuries, 1,083 were lower extremity injuries. Knee and ankle injuries accounted for most of the lower extremity injuries. After the data were weighted for the sampling design and nonresponse, ankle injuries accounted for 40.5 percent of all reported lower extremity injuries, followed by injuries to the knee (29.1 percent), the upper leg (9.6 percent), the lower leg (8.9 percent), the foot or toe (8.8 percent), and other lower extremity sites (3.5 percent). Table 2 shows rates of lower extremity injury by athletes' demographic characteristics. The overall rate of lower extremity injury was 117.0 per 100,000 athlete-exposures (95 percent confidence interval (CI): 100.4, 136.4). Athletes injured their lower extremities more often in games (n = 568) than in practices (n = 334), and injury rates were much higher in games than in practices: approximately four times higher for the lower extremities (204.4 vs. 49.2 per 100,000 athlete-exposures), six times higher for knees (66.7 vs. 10.8 per 100,000 athlete-exposures), and five times higher for ankles (85.6 vs. 16.2 per 100,000 athlete-exposures).
Male athletes had higher rates of injury to the lower extremities, knees, and ankles than did female athletes (table 2). Playing full-contact sports and being seniors were also associated with an increased rate of lower extremity injuries. The overall rates of lower extremity injury in the highest-risk sports (soccer and football) were approximately 4–5 times higher than in the least risky sports, boys' baseball and boys' wrestling (table 2).
Both the unadjusted and adjusted rate ratios indicated that a history of injury was positively associated with prospective lower extremity injuries (table 3). Athletes with a history of lower extremity injury had almost double the rate of lower extremity injuries compared with those without a history of injury (rate ratio (RR) = 1.96, 95 percent CI: 1.62, 2.37). Athletes with a history of knee or ankle injury had an approximately three times' greater rate of prospective knee injury (RR = 2.92, 95 percent CI: 2.09, 4.09) or ankle injury (RR = 3.42, 95 percent CI: 2.44, 4.80).
Use of discretionary protective equipment tended to be associated with a 9 percent decrease in the overall rate of lower extremity injury (RR = 0.91, 95 percent CI: 0.72, 1.15) and a 19 percent decrease in the rate of game injury for all athletes (RR = 0.81, 95 percent CI: 0.57, 1.16) (table 4). The protective effect of use of discretionary protective equipment seemed to be stronger during game sessions, possibly because of an elevated intensity of competition in the game settings, particularly for athletes with no history of lower extremity injuries (RR = 0.74, 95 percent CI: 0.49, 1.09).
Subgroup analysis by equipment item
Analysis of the injury rate according to specific equipment item revealed that the overall 9 percent decrease was an amalgam of two separate effects: a protective effect for kneepad use and an increase in the injury rate associated with brace use. Kneepad use was strongly associated with a reduced rate of knee injury in both game and practice sessions, with the exception of practice injuries among athletes with a history of knee injury (table 5). After adjustment for athletes' demographic characteristics, the overall knee injury rate was 56 percent lower for athletes who used kneepads (RR = 0.44, 95 percent CI: 0.27, 0.74). This protective effect was stronger during game sessions and for athletes with no history of knee injury. The rate of knee injuries in games was 67 percent lower for athletes who reported using kneepads (RR = 0.33, 95 percent CI: 0.16, 0.67). For athletes with no history of knee injuries, kneepad use was associated with a 59 percent reduced rate of knee injury (RR = 0.41, 95 percent CI: 0.23, 0.74).
Use of knee braces or ankle braces, on the other hand, was associated with increased rates of knee and ankle injury, respectively (table 5). The use of knee braces was associated with an elevated rate of knee injury among athletes with no history of knee injury, with an adjusted injury rate ratio of 2.24 (95 percent CI: 1.35, 3.71). Ankle brace use was similarly associated with a higher rate of ankle injury among athletes with no history of ankle injury, with an adjusted injury rate ratio of 2.29 (95 percent CI: 1.24, 4.24).
Of 1,083 reported lower extremity injuries, 14.8 percent (95 percent CI: 10.7, 18.8) were serious injuries. More time was lost due to knee injuries than to ankle injuries, and the proportion of serious (>3 weeks lost) knee injuries was approximately four times higher than that of serious ankle injuries (27.5 percent vs. 6.5 percent).
We used logistic regression to examine the association between use of discretionary protective equipment and the severity of lower extremity injury among injured athletes. After adjustment for sex, grade, type of sport, and past participation in multiple sports, use of discretionary protective equipment tended to be associated with 22 percent lower odds of sustaining serious injury in injured athletes with a history of lower extremity injury (odds ratio (OR) = 0.78, 95 percent CI: 0.41, 1.49) and with 46 percent lower odds for those with no history of lower extremity injury (OR = 0.54, 95 percent CI: 0.26, 1.10). A history of lower extremity injury seemed to be associated with increased odds of sustaining serious injury (OR = 1.34, 95 percent CI: 0.76, 2.37), and a history of knee injury tended to be associated with greater odds of sustaining a serious knee injury (OR = 1.57, 95 percent CI: 0.77, 3.17). However, a history of ankle injury was not associated with increased odds of sustaining a serious ankle injury (OR = 0.90, 95 percent CI: 0.28, 2.91).
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In this study, we determined the rate and severity of lower extremity injuries among athletes in 100 North Carolina high schools participating in 12 organized sports and examined the effect of use of lower extremity discretionary protective equipment. Our findings provide an empirical basis for future research on the effectiveness of discretionary protective equipment and have implications for future intervention strategies. In particular, the finding that kneepad use was associated with a reduced rate of knee injury suggests that consideration should be given to developing and implementing effective intervention strategies to promote kneepad use in high school sports. However, the finding that knee brace use and ankle brace use were associated with increased rates of injury was surprising. Further research is needed to examine this result in more detail.
Use of discretionary protective equipment and injury rate
Consistent with previous research (23–27, 50), the findings from our study indicated that use of lower extremity discretionary protective equipment was associated with a reduced rate of lower extremity injury, as well as with a reduced proportion of serious injuries. The protective effects seemed to be more apparent during games and for athletes with no history of lower extremity injury. However, the positive effect of discretionary protective equipment was largely due to the use of one item, kneepads.
Pads can minimize the effects of direct contact by dissipating impact forces and reducing the force transmitted to soft and hard tissue (30, 31, 36). The highest usage of kneepads was in boys' baseball and girls' softball, sports in which more than 80 percent of players reported having used kneepads (45). Interestingly, these sports also had the lowest knee injury rates. Since so many players used kneepads voluntarily and seemed to benefit, we recommend that the National Federation of State High School Associations review the rules for baseball and softball with a view to requiring kneepad use.
The effect of wearing a brace on the risk of injury is complex and probably depends on the design of the brace, the physical conditioning and dynamic movement characteristics of the athlete, the type of footwear worn, and environmental conditions such as surfacing and weather.  A number of studies have found that braces may minimize knee or ankle injuries (25, 28, 35). However, the evidence for efficacy is generally considered too weak to recommend universal prophylactic knee brace use (28, 50, 51). To our knowledge, this study is one of the first to have examined brace use in high school athletes.
There are at least two plausible mechanisms through which brace use may increase injury risk for the high school athlete. Wearing a brace can increase the athlete's energy expenditure (28, 51, 52). In treadmill tests, oxygen consumption and heart rate were 3–8 percent higher when using a knee brace while running (53). It is therefore plausible that brace use may increase fatigue, which may lead to an increased risk of injury. The plausibility of this mechanism depends upon the weight of the brace and the physical fitness of the athlete; these factors vary greatly between athletes. A second potential mechanism, particularly for knee braces, is slippage or migration of the brace during use. Maintaining the correct position of a knee brace is problematic (26), and some types of knee braces exhibit migration up and down the leg during running (54). Slippage will diminish the protective function of the brace and could conceivably increase injury risk through contact with the hard surfaces of the brace or inappropriate restriction of range of motion.
However, the elevated injury rate we observed with brace use may also be the result of bias from one or more sources (28). First, skilled football players (receivers, kickers, and running backs) may avoid routine brace usage, fearing that braces will limit their speed and agility. Those football players who wear knee braces most frequently may actually be at greater risk for injury (offensive and defensive linemen) (26). Second, many players use knee braces inconsistently. Often, they wear braces in practices but not in games. Third, we examined only “self-reported” use without knowing whether the brace was used on one leg or both. When only one leg is braced, differences in injury risk may affect both the braced leg and the unbraced leg. Albright et al. (28) have noted that an athlete wearing a knee brace may face a higher risk of injury to the unbraced knee.  Fourth, players recovering from injury may return to play earlier if they feel that braces afford protection. Thus, some brace users may be injured players who would not otherwise play. Any or all of these factors could have confounded the association observed in this study. Future research is needed to investigate the relation between brace use and knee and ankle injury, as well as more effectively control for these sources of bias.
Use of discretionary protective equipment and injury severity
Our findings suggest that use of lower extremity discretionary protective equipment was associated with decreased odds of sustaining serious injury to the lower extremities. Although high school sports injuries are seldom severe enough to require hospitalization, the direct medical costs of outpatient treatment and the indirect cost of lost productivity can be high (7, 55). Therefore, modest reductions in injury severity, such as we observed here, may translate into a greatly reduced burden on the health care system and society. Injured athletes' suffering may also be reduced.
Although the North Carolina data allowed us to examine the relations between high school athletes' use of discretionary protective equipment and the rate and severity of lower extremity injuries, these data have several limitations. First, the use of discretionary protective equipment was self-reported and might have been subject to social desirability bias. Second, an athlete's exposure measured in this study used the number of coach-directed game or practice sessions, regardless of the athlete's actual playing time. Because the duration and intensity of each session may vary both within a team and across teams, our assessment of exposure could have been imprecise, particularly for those athletes who “sit on the bench” during game sessions (56). Third, the effect of using discretionary protective equipment may potentially be confounded by behavioral biases: Athletes who choose to use discretionary protective equipment may also adopt other safety behaviors (e.g., warm-ups or stretching) that may reduce their risk of injury. In contrast, users of discretionary protective equipment may believe they are less vulnerable and play more aggressively during games, which may increase their risk of injury. Finally, data on the laterality of use were not collected. In practice, athletes often wear kneepads bilaterally, but they generally wear knee braces and ankle braces unilaterally.
This study found that use of lower extremity discretionary protective equipment tended to be associated with reduced rates of lower extremity injury and reduced odds of serious lower extremity injury. The protective effect of discretionary equipment use was particularly apparent during game sessions and among athletes with no history of lower extremity injury. We found that kneepad use reduced the rate of knee injury, but use of braces was associated with an increased rate of knee or ankle injury. Prospective, well-controlled epidemiologic studies are needed to better address the numerous complex factors underlying the effectiveness of knee braces and ankle braces in high school athletes.
This text is an excellent teaching reference for athletic training students or any person interested in the taping intervention. The author establishes a foundation for the reader, beginning with the basic knowledge of anatomical structures and the biomechanics of the joints and then discussing the appropriate application of tape and braces for treatment or prevention of injuries. There are numerous color illustrations of step-by-step instructions for each taping procedure described; the tape in the illustrations is outlined in black, making it easier for the reader to follow along. The anatomy pictures, published by Primal Pictures, are used to enhance the discussion of the bony, muscular, and surface anatomy for each joint. The text is augmented by palpation landmarks that are highlighted in a table, while new terms are bolded throughout the text and defined in a separate block to provide an easy reference for definitions. The book illustrates normal range of motions for each joint and includes the stretching and strengthening exercises that supplement taping and bracing. The format for each chapter is similar, making the book easy to follow and facilitating the use of the material by the student.
The book is divided into 7 chapters. Chapter 1 establishes the foundation for athletic taping and bracing.  Anatomic knowledge is stressed so that the reader understands the effect of tape and braces on performance. Application and removal techniques are stressed to enhance patient comfort. Chapters 2 through 7 address the 6 major areas of the body that are taped and braced: the foot, ankle, and leg; the knee; the thigh, hip, and pelvis; the shoulder and arm; the elbow and forearm; and the wrist and hand. The most commonly used procedures are discussed. The closed, open, and alternative basket weave taping procedure is emphasized for lateral ankle injuries in chapter 2. This chapter also includes taping procedures for shin splints, the Achilles tendon, heel pain, plus various arch taping and support techniques, as well as an introduction to orthotics. A valid caution is included for a referral to an experienced clinician for the fabrication of orthoses.
The author presents the most common taping techniques for the knee in chapter 3. These include athletic taping for the collateral and cruciate ligaments and the hyperextended knee.  Functional knee braces are discussed as well for the prevention of ligamentous injury or in the athlete's rehabilitation. Using leukotape according to McConnell procedures to control patellofemoral dysfunction also is described, along with typical knee sleeves with straps to help control the patella.
 Chapter 4 covers the use of an elastic wrap to support the thigh, hip, and pelvis and the use of straps for groin, hamstring, and quadriceps strains. Protective pads are discussed for a quadriceps femoris contusion and the bony prominence of the anterior superior iliac spine in a hip pointer. The author follows up with the shoulder in chapter 5, describing the shoulder spica for the glenohummoral joint and similar protective pad construction for the acromioclavicular (AC) joint. A nice addition to this chapter is the description of how to use McConnell taping for the AC joint.
The sixth chapter features the elbow and provides helpful advice about limitations.  For example, the author states that the elbow is difficult to control with tape for collateral ligament injury, but the tape may provide some comfort. Counterforce bracing or taping for epicondylitis is described with a caution for the young athlete and the possibility of an avulsion fracture. The final chapter includes taping for wrist, thumb, and finger sprains. The only finger splint described is that used for a mallet finger.
Overall, this book provides an excellent learning opportunity in basic taping and wrapping techniques, with illustrations that are easy to follow. The anatomy and biomechanics-based rationale for application can help the student to integrate this skill into their problem solving, not only to apply the taping procedures discussed in this book, but to expand this knowledge to new situations.