Background:Shoulder and elbow injuries (SEIs) remain prevalent among high school (HS) baseball players. Pitching restriction (PR) policies were mandated by the National Federation of State High School Associations (NFHS) in 2016 as an injury prevention strategy to set workload limits and reduce overuse injuries. The effect of PR policies on HS baseball SEIs remains unknown. Hypotheses:(1) SEI rates in HS baseball players would be lower in the 3 seasons after PR policy implementation when compared with the 3 seasons before PR policy implementation and (2) specific components of PR policies would be associated with statistically significant decreases in SEI rates. Study Design:Descriptive epidemiological study. Methods:NFHS member state PR policies were obtained from publicly available websites, and components of each policy were analyzed for similarities and differences. SEI/exposure data for US HS baseball players were obtained from High School Reporting Information Online, a sports injury surveillance system. Athletic trainers reported practice and competition injury and athlete-exposure (AE) data from a national school sample during the 2013-2014 through 2018-2019 academic years. Results:During the study period, 295 (164 shoulder, 131 elbow) injuries occurred during 1,554,708 AEs. No statistically significant changes were found in SEI rates, shoulder-specific rates, or elbow-specific injury rates after PR policy mandates were implemented. When analyzing injury rates for practices and competitions collectively, consecutive pitching day rest rules (incidence rate ratio [IRR], 0.32; 95% CI, 0.22-0.46), ≤105 pitch daily maximum (IRR, 0.40; 95% CI, 0.31-0.51), different PR policy rules for regular versus postseason (IRR, 0.43; 95% CI, 0.27-0.65), varsity versus subvarsity pitch count maximums (IRR, 0.46; 95% CI, 0.35-0.59), and ≥4 days' rest if >105 pitch count (IRR, 0.53; 95% CI, 0.42-0.68) provided protective effects against SEIs compared with PR policies without these components. Conclusion:Specific components of PR policies rather than a national PR policy mandate were associated with significant reduction in SEI rates in HS baseball players. The presence of a consecutive pitching day rest rule and daily maximum pitch count of ≤105 pitches were associated with significant reductions in SEIs based on total (practice and competition) exposures, practice exposures, and competition exposures.

Background:The 15-to-19-year-old age group of baseball pitchers has an annual ulnar collateral ligament reconstruction (UCL-R) surgical incidence that is higher than any other demographic, and recent trends among elite pitchers show steady declines in average age of first UCL-R. There is a paucity of literature evaluating the impact of early-career UCL-R on an elite pitcher's professional career, including performance, career longevity, and career earnings. Methods:Demographic, high school showcase, professional performance, injury data, and earnings from pitchers selected in the first 5 rounds of the Major League Baseball (MLB) draft (2011-2020) were gathered from publicly available databases. One-way between-groups analysis of variance for continuous variables comparing 3 UCL-R groups (early, middle, and late career) with a control group (no UCL-R) was performed, and multivariable linear regression for outcomes significant upon analysis of variance was conducted. Standard deviations (SDs) of ±1 SD were used to define early, middle, and late career UCL-R subgroups after normal distribution was confirmed (Shapiro-Wilk test, P = .188). The early-career UCL-R group was defined as ≤ -1 SD (19.49 years), while the late-career UCL-R group was defined as ≥ +1 SD (25.67 years). Results:Of 851 pitchers, 281 (33.0%) had undergone primary UCL-R at manuscript preparation. Compared to early-career UCL-R pitchers, median MLB career earnings (adjusted for inflation) were significantly higher for middle- (P = .047) and late-career UCL-R pitchers (P < .001) following adjustment for confounders including age. UCL-R return to sport recovery time (any level) for primary reconstruction was significantly longer for early-career UCL-R compared to late-career UCL-R pitchers (19.79 ± 5.69 vs. 15.36 ± 3.45 months, P = .023). Conclusion:Early-career UCL-R may be associated with lower MLB career earnings compared to middle-to-late-career UCL-R surgery in a cohort of high-round MLB draft pitchers. In addition, prolonged recovery time following early-career UCL-R may result in an increased mental health burden that warrants further investigation.

BACKGROUND:Previous studies have reported that spondylolysis occurs predominantly at the L5 and L4 levels, with defects at higher levels occurring in <5% of cases. However, computed tomography and radiography were the primary imaging modalities in these studies. Current evidence regarding diagnostic imaging for pediatric lumbar spondylolysis suggests that magnetic resonance imaging (MRI) is as accurate as computed tomography in detecting early stress reactions of the pars interarticularis or pedicles without fractures while avoiding radiation exposure. The early detection of spondylolysis results in a higher likelihood of bony union and a decreased likelihood of spondylolisthesis. HYPOTHESIS:The increased use of MRI may reveal a larger proportion of spondylolysis in patients who experience an injury at a higher spinal level than previously reported. STUDY DESIGN:Cross-sectional study; Level of evidence, 3. METHODS:The medical records of 902 pediatric and adolescent athletes (364 female, 538 male) diagnosed with symptomatic pars interarticularis and pedicle stress injuries at 2 academic medical centers between 2016 and 2021 were retrospectively reviewed. All patients had MRI scans taken at the time of diagnosis. Only patients with pars/pedicle edema on MRI were included. Data regarding spondylolysis stage, spinal level of injury, unilateral versus bilateral injury, sport participation, and MRI protocol over the 5-year study period were analyzed. RESULTS:Male patients presented at older ages than female patients (P < .001). Soccer was the most common sport at symptom onset and the second most common single-sport activity among those who specialized (participating in 1 sport year-round at the exclusion of others), behind gymnastics. The mean symptom duration was 4.0 months. Although most patients (83.5%) had exclusively lower lumbar stress injuries, 9.1% of injuries occurred at or above the L3 level. Over half of the patients had active single-level pars/pedicle fractures on MRI, with a mean symptom duration before presentation in this subgroup of 4.0 months. Even when pars/pedicle stress reactions were excluded from analysis, 7.1% of patients were injured at or above the L3 level. CONCLUSION:Among male and female athletes aged 8 to 21 years presenting with symptomatic pars interarticularis and pedicle stress injuries evaluated by MRI at the time of initial diagnosis, there was a higher incidence of upper lumbar stress injuries than previously reported.

BACKGROUND:Recent studies utilizing magnetic resonance imaging (MRI) for the evaluation of symptomatic lumbar spondylolysis in pediatric and adolescent athletes have indicated that upper level lumbar involvement has a higher incidence than previously reported. There has been a paucity of literature evaluating sport-specific patterns of lumbar spondylolysis, specifically upper versus lower level involvement. PURPOSE:To assess the potential risk factors for upper level stress injuries of the lumbar spine in pediatric and adolescent athletes. STUDY DESIGN:Cross-sectional study; Level of evidence, 3. METHODS:The medical records of 902 pediatric and adolescent athletes (364 female, 538 male; mean age, 14.5 ± 2.1 years) diagnosed with symptomatic pedicle and pars interarticularis stress injuries at 2 academic medical centers (July 2016 to June 2021) were reviewed. All patients had undergone MRI at the time of diagnosis. Only patients with pars/pedicle edema on MRI were included. Data regarding single-sport specialization, sport participation, sport category by biomechanics (axial rotation vs extension/axial loading), and vertebral level of injury over the 5-year period were analyzed. Stress reaction or active spondylolysis (SRAS) was the terminology used to designate grade 1, 2a, or 3 stress injuries according to the adapted Hollenberg classification system on MRI. Upper level vertebrae were defined as L3 or superior, whereas lower level vertebrae included L4 or inferior. RESULTS:Of the 902 patients with SRAS injuries, most (n = 753 [83.5%]) had exclusively single-level lower stress injuries, while 67 (7.4%) had multilevel stress injuries. There were 82 athletes (9.1%) who had single-level upper stress injuries. Athletes with upper level pars/pedicle stress injuries were older at the time of diagnosis (15.8 ± 1.9 vs 14.3 ± 2.1 years, respectively; P < .001), had a shorter duration of low back pain before presentation (2.50 ± 2.70 vs 4.14 ± 6.73 months, respectively; P < .001), were more likely to specialize in a single sport (43.9% vs 32.3%, respectively; P = .046), and had a lower incidence of active spondylolysis on MRI at the time of diagnosis (42.7% vs 59.8%, respectively; P = .004) compared with athletes with lower level stress injuries. Athletes with lumbar stress injuries who specialized in a single sport had nearly twice the odds of having upper level involvement compared with multiple-sport athletes (adjusted odds ratio, 1.80 [95% CI, 1.06-3.04]; P = .03). Athletes with active spondylolysis on MRI at the time of diagnosis had nearly half the odds of having upper level involvement (adjusted odds ratio, 0.55 [95% CI, 0.33-0.91]; P = .02). CONCLUSION:Age at the time of diagnosis, duration of low back pain, single-sport specialization, and presence/absence of active spondylolysis on MRI at the time of diagnosis were primary predictors of whether an athlete's lumbar stress injury was classified as either upper or lower level involvement. Overall, the variables included in multivariate analysis were modest predictors, explaining only 15.1% of the variance in the rates of lumbosacral stress injuries classified by spinal level. These specific biomechanical factors and other potential contributors to these findings warrant further investigation.

INTRODUCTION The development of pitch counts (PCs) was instituted as 1 approach to combat throwing-related overuse injuries in baseball. Pitch count were first introduced in 1996 based on small sample survey data and opinion.1 Two years later, data showed that injury risk in a game increased 20% for every inning pitched and 10% for every 10 pitches thrown.2 Thus, this evidence indicated that PC could be a potential guardrail for overuse injury risk. In 2006, USA Baseball published recommendations that further provided guidance of pitches per game based on age level.1 In 2010, Little League Baseball followed suit and updated PC recommendations even further.3 Research has shown an association between pitchers reporting pain and pitches per game, per season, pitching months per year, games per year, innings per game, and warm-up pitches before a game.4,5 As PC began to develop into 1 of the primary approaches to reduce overuse injuries, suboptimal compliance and enforcement of these guidelines became a concern for all parties involved (eg, sports medicine team members, athletes, coaches, league and tournament administrators, and caregivers).6 Data published in 2015 indicated that in addition to overuse, pitchers with greater velocity were at an increased risk of throwing-related injury.7 As the evolution of PC continued to progress, further guidelines were introduced. In 2014, Major League Baseball (MLB) introduced Pitch Smart, a collaborative effort between USA Baseball and MLB to produce a comprehensive resource for safe pitching practices.8 In 2016, the National Federation of State High School Associations followed this example with its Pitching Policy Rule 6-2-6.9 99.9 In 2019, the Japanese National High School Baseball Federation enacted its own PC policy as a measure to reduce overuse throwing-related injuries.10 Unfortunately, despite tremendous outreach, publicity, evidence-based data, and endorsement from professional athletes, overuse pitching injuries have not declined. For example, ulnar collateral ligament (UCL) injuries in nonprofessional pitchers continue to rise.11,12 In particular, 1 of the most well-known sports medicine practices in the United States has documented the increasing percentage of UCL reconstructions among youth and HS pitchers despite the evolution of pitch restriction policies (Figure). Therefore, despite well-intentioned overuse throwing injury prevention policies, 1 must entertain other potential risk factors beyond voluminous pitching practices.Figure.: UCL surgeries for baseball pitchers at youth and high-school level.NONCOMPLIANCE AND GAPS IN POLICIES As more guidelines are implemented, it is understandably challenging, and at times perplexing, for athletes, coaches, caregivers, and tournament administrators to stay consistent with adherence, particularly across different leagues with decreased consistency across state and tournament guidelines. In tournament settings, noncompliance with Pitch Smart guidelines has been documented to involve more than 90% of teams and almost half of all pitchers in a single state over a single summer season.13 Inadequate rest was the most common violation, with other noncompliance factors including/involving pitching in consecutive games, volume of pitching, and younger age of pitchers.13 It should be noted and emphasized that upward of 4 million athletes participate in Pitch Smart-compliant baseball leagues.14 Further challenges and confusion may occur because there is inconsistency across states with varying PC guidelines at the HS level (Table 1). TABLE 1. - Pitch Count and Days of Rest Protocols by State52–95 State 1st Season Implemented Version Reviewed Rules Vary by Month? Max Pitches 0 1 2 3 4 Consecutive Pitching Days Rest Rule Weekly Max Pitch Count AL 2016-2017 2023 No 100ab, 120cd 1-25 26-50 51- 75 76+ None None AK 2016-2017 2022 Yes 100e, 120f 1-25e, 1-30f 26-45e, 31-55f 46-65e, 56-80f 66-85e, 81-105f 86-100e, 106-120f Mandatory 1 day rest for pitcher pitching 2 consecutive days None AZ 2016-2017 2023 No 95 ab, 105 cd 1-20a, 1-30bcd 21-35a, 31-45bcd 36-50a, 46-60bcd 51-65a, 61-75bcd 66+a, 76+bcd None None AR 2016-2017 No 85g, 110h 1-30 31-60 61-85 86-110 None None CA 2016-2017 No 90g, 110h 1-30 31-50 51-75 76+ None 30 outs and/or 3 appearances per calendar week CO 2015-2016 2023 No 85g, 110h 1-25g, 1-35h 26-35g, 36-60h 36-60g, 61-85h 61-85g, 86-110h 60+ pitches over 2 d-> 1 d resth, 35+ pitches over 2 d-> 2 d restg None CT 2016-2017 2023 No 110 1-25 26-50 51-75 76+ None None DE 2016-2017 Yes 105 1-25 26-50 51-80 81-105 None 205/w FL 2015-2016 No 95ab, 105cd 1-20a, 1-30bcd 21-35a, 31-45bcd 36-50a, 46-60bcd 51-65a, 61-75bcd 66+a, 76+bcd None None GA 2016-2017 No 90g, 110h 1-24g, 1-35h 25-44g, 36-60h 45-64g, 61-85h 65-90g, 86-110h 110h/90g pitch max in 2 d; mandatory 1 d rest for pitcher pitching 2 consecutive days None HI 2016-2017 2017 No 110 1-35 36-60 61-85 86+ 110 pitches in 2 d; no pitcher eligible for pitching 3 consecutive days None ID 2016-2017 2023 Yes 85g, 110h 1-25g, 1-35h 26-35g, 36-60h 36-60g, 61-85h 61-85g, 86-110h 100h/60g pitch max in 2 d; no pitcher eligible for pitching 3 consecutive days None IL 2016-2017 No 95g, 105h 1-30 31-45 46-60 61-75 76+ Pitch cap of 45 pitches on 3rd consecutive day 4 appearances per calendar week IN 2016-2017 2017 No 90g, 120h 1-25g, 1-35h 26-35g, 36-60h 36-60g, 61-80h 61-80g, 81-100h 81-90 + g, 101-120 + h 60+ pitches over 2 d-> 1 d rest None IA 2016-2017 2019 No 90a, 110bcd 1-25 26-40 41-65 66-90 91-110bcd 110h/90g pitch max in 2 d; 2 or more-day total would determine # of required rest days 150/wka, 180/wkbcd (through 1st week of June) KS 2016-2017 2017 No 105 1-30 31-45 46-60 61-75 76+ None None KY 2015-2016 No 110g, 120h 1-25 26-40g, 26-50h 41-65g, 51-75h 66 + g, 76 + h None None LA 2017-2018 No 125 1-30 31-50 51-75 76+ None None ME 2016-2017 2020 No 90g, 110h 1-15g, 1-20h 16-35g, 21-40h 36-55g, 41-65h 76-90g, 96-110h None None MD 2016-2017 2019 No 95a, 105bcd 1-30 31-45 46-60 61-75 76+ None None MA 2019-2020 2020 No 95g, 115h 1-25 26-40 41-55 56-70 71-95g, 71-115h None If pitcher threw 71-90 pitches on last day he pitched, on his 4th day of rest, he wouldd be eligible to throw 25 pitches max MI 2016-2017 No 105 1-25 26-50 51-75 76+ None None MN 2016-2017 2021 No 85g, 105h 1-25g, 1-30h 26-35g, 31-50h 36-60g, 51-75h 61-85g, 76-105h Mandatory 1 d rest for pitcher pitching 2 consecutive days None MS 2016-17 2017 No 120 1-25 26-50 51-75 76-105 106-120 None None MO 2016-2017 2020 No 95ab, 105cd 1-30 31-45 46-60 61-75 76+ Mandatory 1 d rest for pitcher pitching 2 consecutive days None NE 2016-2017 2021 Yes 90g, 110h 1-30h 1-30g, 31-50h 31-50g, 51-70h 51-70g, 71-90h 71-90g, 91-110h No player may make more than 2 appearances as a pitcher during any consecutive 3-d period None NV 2016-2017 2023 No 110 Pitcher may not throw >140/>150 pitches during any 4 consecutive days of regular season/postseason play. In addition, no more than 11 innings/33 outs during 4 consecutive days NH 2016-2017 2022 No 100g, 120h 1-25 26-40 41-65g, 51-75h 66 + g, 76 + h None None NJ 2016-2017 2022 No 110 1-30 31-50 51-70 71-90 91-110 A pitcher cannot pitch on 3 consecutive calendar days 150 pitches in a 5-d calendar period NM 2016-2017 No 105g, 120h 1-40 41-60 61-90 91+ If pitcher pitches on consecutive days and exceeds 60 pitches over 2 d, the cumulative pitch count must be used to calculate required rest period. If a pitcher pitches 2 consecutive days AND is eligible to pitch a 3rd consecutive day, the max pitch count on day 3 will be 60 None NY 2016-2017 2022 Yes 85g, 125h 1-30g, 1-40h 31-45g, 41-71h 46-75g, 72-102h 76-85g, 103-125h None None NC 2016-2017 2020 No 105 1-30 31-45 46-60 61-75 76+ Mandatory 1 d rest for pitcher pitching 2 consecutive days None ND 2016-2017 2017 No 120 1-30 31-45 46-60 61-75 76-120 None None OH 2016-2017 No 125 1-30 31-50 51-75 76+ None None OK 2016-2017 2023 No 120 1-35 36-50 51-75 76-100 101-120 None None OR 2016-2017 2023 No 110 1-25 26-45 46-60 61-85 88-110 None If pitcher threw 61-85 pitches on last day he pitched, on his 3rd day of rest, he would be eligible to throw max 45 pitches. If he threw <25 pitches on that 3rd rest day, he would be eligible to throw the next day with 110-pitch maximum. If he threw 26-45 pitches on that 3rd rest day, he would need 1 full day of rest before pitching again PA 2016-2017 2020 No 100 1-25 26-50 51-75 76-100 No pitcher may appear on more than 2 consecutive days of competition 200 pitches in a calendar week (Sunday-Saturday) RI 2016-2017 2023 No 110 1-25 26-50 51-75 76-110 None None SC* 2016-2017 No 75g, 110h 1-30 31-45 46-60 61-75 76-90h If pitcher throws in consecutive days, his cumulative total of pitches for those 2 d will determine the # of days of rest required None SD 2008-2009 2022 No 105 1-30 31-45 46-60 61-80 81+ No player may make more than 2 appearances as a pitcher during any consecutive 3-day period None TN 2016-2017 No 100g, 120h 1-25 26-40g, 26-55h 41-65g, 56-75h 66-80g, 76-105h 81-100g, 106-120h A pitcher cannot pitch on 3 consecutive calendar days None TX 2016-2017 2017 No 110 1-30 31-45 46-65 66-85 86-110 If pitcher is used twice in a 3-day series, the rest day start period will begin after the second appearance even if there was a day of rest in between In multigame series or tournament, pitch count can be divided into separate appearances as long as combined total does not exceed appropriate pitch count max. Days of rest will be determined by FINAL pitch count of the series or tournament UT 2016-2017 2017 No 110 1-35 36-60 61-85 86-110 No pitcher may throw more than 75 pitches in 2 d; if this occurs, there will be 1 d of required rest None VT 2007-2008 2023 No 110g, 120h 1-25 26-40g, 26-50h 41-65g, 51-75h 66 + g, 76 + h None None VA 2016-2017 2022 No 110 1-25 26-50 51-75 76-100 101+ If a pitcher throws 51+ pitches over 2 consecutive days, at least 1 calendar day of rest must be observed, with days of rest required determined by # of pitches thrown on day 2 of consecutive days. If 3rd consecutive day of pitching occurs, pitcher is limited to 25 pitch max on that 3rd consecutive day. At least 1 d of rest must be observed after 3 consecutive days of pitching None WA 2016-2017 2023 No 105 1-30 31-50 51-75 76-105 None None WV 2016-2017 No 110 1-30 31-50 51-75 76-110 No pitcher can pitch 4 (4) consecutive days None WI 2016-2017 No 100 1-30 31-49 50-75 76-100 None None Key: a-freshman, b-sophomore, c-junior, d-senior; e-early season (3/17-4/28), f-late season (4/28-end); g-Sub-Varsity (eg, fresh, soph, JV teams), h-Varsity; i-first 30 days of season, j-after 30 d.*South Carolina mandates 5 days of rest if pitching 91 to 110 pitches. Like any well-intended guideline or injury prevention policy, pitching restriction policies, whether at the youth, adolescent, or HS level, are subject to interpretation. Consequently, gaps (or loopholes) are often inadvertently created, which can weaken the policies and increase injury risk, solely based on interpretation. For example, days of rest are frequently calculated as “per calendar day” in pitching restriction policies, including Pitch Smart and for most NFHS-sanctioned HS baseball leagues.8,59 However, a calendar day is not the same as a 24-hour period. Unless the pitching restriction policy discretely defines a calendar day as a 24-hour period (eg, 24 hours since the pitcher's last pitch, or beginning at midnight after the day pitched and ending at midnight the following evening), days of rest based on calendar days can be subject to loose interpretation. Furthermore, the intent of pitching restriction policies is that no pitching is allowed to occur on a day of rest. Compounding this dilemma is that pitching restriction policies only include in-game pitches and often underestimate workload on a given day's outing. Data at the high school and major league levels indicate that 42% to 45% were not accounted for in PC monitoring when including nonlive game pitches.60,61 VELOCITY AND WEIGHTED BALL PROGRAMS A significant amount of emphasis has been placed on throwing velocity in recent years. Many players see throwing velocity gains as a means to improve performance and advance to higher levels of baseball. Therefore, weighted ball velocity throwing (WBV) programs have gained in popularity across all levels of baseball as they have been shown to enhance throwing velocity.62–67 Pitchers drafted in the top 5 MLB rounds reached 90 mph at the average age of 16.7 years in 2020, the youngest age when assessing HS showcase data from 2011 to 2020 (range of 16.7-17.3 years).68 There has been concern from noted experts in the baseball throwing community that the rise in baseball pitching injuries is associated in part because of the rise in pitching velocity.7,64,69 One culprit for this velocity spike in recent years is the growth, interest, and utilization of WBV programs. Although WBV programs allow pitchers to achieve higher pitch velocity, they have also been associated with greater injury risk and increased stress on the throwing shoulder and elbow.70–73 These effects on the throwing arm have been believed to be because of a significant gain in shoulder external rotation (ER) range of motion. In fact, data have demonstrated that enhanced shoulder ER PROM correlates with increased pitch velocity and increased shoulder and elbow forces.74–77 Hence, a risk versus reward discussion is warranted in relation to WBV programs, especially in skeletally immature baseball players.78 Specifically, epiphyses are 2 to 5 times weaker than the neighboring osseous tissue. Regarding the elbow, the medial epicondylar epiphysis does not fuse until approximately 15 to 16 years of age, putting this aspect of the elbow at risk of osseous injury in overhead throwers.79 Therefore, as a sports medicine community, we need to consider the velocity improvements imparted by WBV programs when developing updated PC guidelines. WORKLOAD Workload has been defined as the sport and nonsport burden as a stimulus that is applied to an individual human biological system over varying time periods and with varying magnitude (ie duration, frequency, and intensity).80 Although there has been growing interest and study on the importance of PC in the prevention of overuse throwing-related injuries in baseball, an equally exciting and evolving area of throwing medicine involves workload in the throwing athlete. Research has indicated that high workloads are associated with injury in numerous sports.81–84 However, there have been limited data until recently on the concept of workload and its application to baseball pitchers. Furthermore, there is at times potential confusion of how to define workload in a baseball pitcher. Volume of pitches thrown (aka the PC) has at times been believed to be analogous to workload.85 However, this should be clarified. Although PC are an important factor in the workload of a baseball pitcher, they are but 1 component of workload.86,87 Workload, as it pertains to baseball pitchers, includes the combination of PC, velocity, fatigue levels, effort, and other internal and external factors that should be taken into consideration in workload management.7,60,88–92 Further research is needed to accurately quantify workload with relation to baseball pitchers and injury risk. OFF-SEASON TRAINING PROGRAMS: TO THROW OR NOT TO THROW? For the adolescent and HS pitcher, debate continues regarding the ideal amount of throwing during a calendar year to allow development but not increase injury risk. Pitch Smart guidelines for 15 to 18-year-olds recommend that players take at least 4 months off from competitive pitching each year, including at least 2 to 3 continuous months off from all overhead throwing.61 There is an important distinction between year-round throwing and year-round pitching. Proponents of year-round throwing for amateur pitchers cite benefits of a 3-to-4-month off-season throwing program, which allows adequate time for “on-ramping” (eg progression from no/low-volume throwing to max-effort throwing) over the first 1 to 2 months, followed by 3 to 4 weeks of velocity training (ie, pushing boundaries via scheduled throwing at max effort), followed by 1 to 4 weeks of mound development (ie, pitch design, command work, or bullpens getting ready for season).93 Critics of year-round throwing explain that pitchers need time off from throwing to gain anterior shoulder stability (by avoiding activities like throwing that increase shoulder external ROM), improve rotator cuff strength and scapular stability, perform manual resistance rotator cuff exercises, restore shoulder and elbow ROM, reduce muscle damage resulting from in-season throwing volumes over 8 to 9 months, to allow low-grade injuries to heal, and to prioritize other competing demands (eg, strength and conditioning).94,95 RECOMMENDATIONS Challenges to reduce overuse throwing injuries, in particular at the adolescent levels, are numerous. As previously elaborated, PC policies from well-known and respected baseball medicine associations alone have not been enough to alter the trajectory of overuse throwing injuries. However, the authors propose the following recommendations to provide a progression in the PC policies already implemented (Table 2). TABLE 2. - Additional Recommendations for Reducing Overuse Throwing Injuries Enforcement of PC policies in non–high-school baseball competition including tournaments, which are not under the regulations of state high-school associations with penalties applied to the coach and team if not followed Consistency and standardization of PC policy guidelines by state including non–high-school baseball programs based on age level, similar to MLB PitchSmart. This will ease confusion, particularly when traveling across state lines96 If any pitcher throws 25 pitches in a game, no live game pitching the next day if 14 years or older* No pitching off a mound on consecutive days if less than 14 years old Recommend all HS state athletic associations allow for a formalized 4-wk preseason throwing ramp up period before the first day of practice for pitchers and catchers to minimize preseason and early season overuse throwing injuries97–100 WBV programs should be avoided in preadolescent and adolescent throwing athletes. If used, particularly in skeletally immature athletes, WBV programs should be combined with an overall kinetic chain training program under the supervision of experts and focusing on efficient throwing mechanics63,78,101–103 *Of note, the average number of HS live game pitches per inning is between 17 and 18.60 CONCLUSIONS As overuse injury data have evolved since PC introduction, PC policies remain inconsistent across states, and opinions by well-respected members of the baseball training community remain conflicted. Thus, it is understandable that a standardized approach to overuse injury prevention in pitchers remains elusive. With the growth of performance programs including WBV training coupled with PC policies that have not been updated since 2014, there is a critical need for sports medicine researchers to partner with the baseball training community to evaluate the effectiveness of such injury prevention programs, including an evolution of PC policies that consider year-round and/or off-season workloads and WBV training.

Background: Showcase participation has been considered a risk factor for elbow injuries. It remains unclear whether high school (HS) showcase volume negatively affects pitchers’ career paths. Because pitchers are achieving 90 mph thresholds at younger ages, it is unknown whether shorter time intervals between achieving 90 mph thresholds and dates of ulnar collateral ligament reconstruction (UCL-R), known as time to tear (TTT), may affect career trajectory. Hypothesis: Elite pitchers with higher HS showcase volumes would be less likely to reach Major League Baseball (MLB) level compared with elite pitchers with fewer HS showcase appearances. Elite pitchers with longer TTT intervals would be more likely to achieve MLB level. Study Design: Cohort study; Level of evidence, 3. Methods: Demographic, HS showcase and professional performance, and injury data from pitchers selected in the first 5 rounds of the MLB draft (2011-2017) were gathered from publicly available databases. Continuous and categorical variables were compared for the following subgroups: UCL-R group and pitcher group not undergoing UCL-R; “early” and “late” UCL-R groups; and pitchers achieving and pitchers not achieving MLB level. Multivariable analysis was performed using logistic regression. Standard deviations of ±1 SD were used to define early career versus late career UCL-R subgroups after normal distribution was confirmed (Shapiro-Wilk test; P = .227). The early UCL-R group was defined as those pitchers undergoing UCL-R ≤−1 SD from the mean age at first injury (group mean age, 19.43 years), whereas the late UCL-R group was defined as ≥+1 SD from that age (group mean age, 25.19 years). Results: Of 611 pitchers, 455 (74.5%) had HS showcase performance data, and 608 (99.5%) had professional performance data. In total, 184 (30.1%) pitchers underwent UCL-R. Fewer pitchers who underwent early UCL-R achieved the MLB level compared with pitchers who underwent late UCL-R (48.1% vs 86.2%; P = .006). Elite pitchers who pitched in ≥10 showcases in HS had half the odds of achieving the MLB level compared with pitchers who participated in <10 HS showcases (adjusted odds ratio, 0.50; 95% CI, 0.29-0.86; P = .012). For every year longer that an elite pitcher did not tear his UCL after achieving the 90 mph threshold at an HS showcase (TTT after 90 mph [per year]), the likelihood of achieving the MLB level increased by 24% (adjusted odds ratio, 1.24; 95% CI, 1.02-1.52; P = .032). Conclusion: Higher HS showcase volume in elite pitchers was associated with a lower likelihood of achieving MLB level. A longer TTT after 90 mph (per year) was significantly associated with achieving MLB level in elite pitchers.

Background: Ulnar collateral ligament reconstruction (UCLR) surgeries have increased significantly in amateur and professional baseball pitchers. Although showcase participation has been considered an injury risk factor, limited data are available to corroborate this association. Hypothesis: Elite pitchers achieving fastball velocities ≥90, ≥92, and ≥95 mph at younger ages would be more likely to undergo UCLR earlier in their careers compared with pitchers not achieving these velocity thresholds at younger ages. Elite pitchers participating in high showcase volumes would be more likely to undergo UCLR compared with elite pitchers participating in fewer showcases. Study Design: Cohort study; Level of evidence, 3. Methods: Descriptive, showcase performance, and injury data from pitchers selected in the first 5 rounds of the Major League Baseball draft (2011-2020) were gathered from publicly available databases. Continuous and categorical variables for pitchers undergoing UCLR and those not undergoing UCLR were compared, and multivariable analysis was performed using logistic regression. We used standard deviations (SDs) of ±1 SD of mean age at first UCLR to define early-career versus late-career UCLR subgroups after normal distribution was confirmed (Shapiro-Wilk test; P = .183). The “early” UCLR group was defined as ≤−1 SD (19.09 years), whereas the “late” UCLR group was defined as ≥+1 SD (24.79 years). Trends in time were evaluated using linear regression. Results: Of the 845 pitchers selected, 659 pitchers (78.0%) had retrievable showcase performance data. Of the 845 pitchers, 229 (27.1%) underwent UCLR. Peak fastball velocity recorded at showcases was the strongest predictor of UCLR (adjusted odds ratio, 1.19; 95% CI, 1.02 to 1.39; P = .03). Peak fastball velocity in high school (HS) was significantly higher among pitchers who underwent UCLR compared with pitchers in the no-UCLR group (91.57 vs 90.71 mph, respectively; 95% CI, −1.43 to −0.29; P < .01). Age at which pitchers participated in their first HS showcase was significantly younger for the early versus the late UCLR group (15.53 vs 16.51 years, respectively; 95% CI, −1.53 to −0.41; P < .01). Elite pitchers with early UCLR participated in nearly twice as many showcases compared with the late UCLR group (5.38 vs 2.89, respectively; 95% CI, 0.43 to 4.54; P = .02). The mean number of HS showcases that elite pitchers attended more than doubled during the 2011-2020 study period (from 2.88 to 6.00 total showcases; P < .001). Mean age at which pitchers attended their first HS showcase steadily declined as well over the 10-year period (from 16.52 to 15.63 years; P < .001). Conclusion: Peak fastball velocity was the strongest predictor of UCLR in elite pitchers before initiating professional careers. Elite amateur pitchers attended more showcases at younger ages in a decade-long trend. Overall, the variables included in this multivariable analysis were weak predictors, explaining only 3.8% of the variance in UCLR rates.

Background: BEAR (bridge-enhanced anterior cruciate ligament [ACL] restoration), a paradigm-shifting technology to heal midsubstance ACL tears, has been demonstrated to be effective in a single-center 2:1 randomized controlled trial (RCT) versus hamstring ACL reconstruction. Widespread dissemination of BEAR into clinical practice should also be informed by a multicenter RCT to demonstrate exportability and compare efficacy with bone--patellar tendon–bone (BPTB) ACL reconstruction, another clinically standard treatment. Purpose: To present the design and initial preparation of a multicenter RCT of BEAR versus BPTB ACL reconstruction (the BEAR: Multicenter Orthopaedic Outcomes Network [BEAR-MOON] trial). Design and analytic issues in planning the complex BEAR-MOON trial, involving the US National Institute of Arthritis and Musculoskeletal and Skin Diseases, the US Food and Drug Administration, the BEAR implant manufacturer, a data and safety monitoring board, and institutional review boards, can usefully inform both clinicians on the trial’s strengths and limitations and future investigators on planning of complex orthopaedic studies. Study Design: Clinical trial. Methods: We describe the distinctive clinical, methodological, and operational challenges of comparing the innovative BEAR procedure with the well-established BPTB operation, and we outline the clinical motivation, experimental setting, study design, surgical challenges, rehabilitation, outcome measures, and planned analysis of the BEAR-MOON trial. Results: BEAR-MOON is a 6-center, 12-surgeon, 200-patient randomized, partially blinded, noninferiority RCT comparing BEAR with BPTB ACL reconstruction for treating first-time midsubstance ACL tears. Noninferiority of BEAR relative to BPTB will be claimed if the total score on the International Knee Documentation Committee (IKDC) subjective knee evaluation form and the knee arthrometer 30-lb (13.61-kg) side-to-side laxity difference are both within respective margins of 16 points for the IKDC and 2.5 mm for knee laxity. Conclusion: Major issues include patient selection, need for intraoperative randomization and treatment-specific postoperative physical therapy regimens (because of fundamental differences in surgical technique, initial stability construct, and healing), and choice of noninferiority margins for short-term efficacy outcomes of a novel intervention with evident short-term advantages and theoretical, but unverified, long-term benefits on other dimensions.

Background: Pediatric sports-related injuries are common, yet prevention efforts too often go unevaluated. Collins et al. studied nine U.S. high school (HS) sports during 2005/06-2006/07, finding boys’ and girls’ soccer had the highest injury rates related to illegal activity. Several states have implemented yellow card accumulation policies (YCPs) in an effort to prevent injuries. Hypothesis/Purpose: Purpose: Evaluate the effectiveness of YCPs in reducing HS soccer competition injuries by comparing injury rates and patterns in states with and without YCPs. Hypotheses: Athlete-athlete contact injury rates are lower in states with YCPs Severe injuries (concussion, fracture, ACL, injury requiring surgery, injury resulting in > 3 weeks’ time loss) are less prevalent in states with YCPs Gender differences influence the effectiveness of YCPs Methods: Retrospective cohort study of NHFS member state association HS soccer players injured during competition in 2005/06-2017/18. Athlete exposure (AEs) and injury data collected from a national sports injury surveillance system, High School RIO. Poisson regression assessed the effects of YCPs on injury rates and patterns. Results: Of 50 NFHS member states associations, high schools from 47 were represented. Overall, 901 athlete-athlete contact injuries occurred during 352,775 competition AEs in states with YCPs and 3,525 during 1,459,708 AEs in states without YCPs. There was no significant difference in overall contact injury rates (rate ratio [RR] 1.06; 95% confidence interval [CI]: 0.98-1.14) between schools in states with and without YCPs. A small, significant increase in overall contact injury rates was discernable after states’ adoption of YCPs (RR 1.17; 95% CI: 1.03, 1.34), particularly in boys’ soccer (RR 1.32; 95% CI 1.08-1.62). A significantly lower proportion of injuries resulting in > 3 weeks’ time loss occurred in states with YCPs (injury proportion ratio [IPR] 0.81; p=0.047), while other severe injuries did not differ. There were no significant differences in YCPs’ effect by gender (p=0.319). Conclusion: Among HS boys’ and girls’ soccer players, playing in states with YCPs did not lower athlete-athlete contact injury rates, although injuries resulting in > 3 weeks’ time loss were less prevalent in states with YCPs. Athlete-athlete contact injury rates were slightly higher in states following adoption of YCPs, particularly in boys’ soccer. Enactment of YCPs alone, without proper enforcement, may not be a sufficient injury prevention strategy. Further studies assessing the impact of HS soccer YCPs need to consider the effects of state level YCP enforcement, documented illegal activity/foul play, and Fair Play education. Tables/Figures: Table 1. Rate of Athlete-Athlete Contact Injuries Sustained During Soccer Competition in High Schools in States with and without Yellow Card Policies, National High School Sports-Related Injury Surveillance Study, USA, 2005/06-2017/18 # Injuries # Competition AEs Rate per 10,000 AE RR (95% CI) a Overall With YCP 901 352775 25.5 1.06 (0.98, 1.14) Without YCP 3525 1459708 24.1 Ref Boys’ Soccer With YCP 430 188626 22.8 1.10 (0.99, 1.22) Without YCP 1625 783851 20.7 Ref Girls’ Soccer With YCP 471 164149 28.7 1.02 (0.92, 1.13) Without YCP 1900 675857 28.1 Ref aRate Ratio (RR) is the ratio of total injury rate in YCP schools to total injury rate in No YCP schools. Table 2. Rate of Athlete-Athlete Contact Injuries Sustained During Soccer Competition in High Schools in states with Yellow Card Policies Pre- and Post- Policy Enactment, National High School Sports-Related Injury Surveillance Study, USA, 2005/06-2017/18 # Injuries # Competition AEs Rate per 10,000 AE RR (95% CI) a Overall Post-YCP 901 352775 25.5 1.17 (1.03, 1.34) Pre-YCP 285 130686 21.8 Ref Boys’ Soccer Post-YCP 430 188626 22.8 1.32 (1.08, 1.62) Pre-YCP 118 68262 17.3 Ref Girls’ Soccer Post-YCP 471 164149 28.7 1.07 (0.90, 1.28) Pre-YCP 167 62424 26.8 Ref aRate Ratio (RR) is the ratio of total injury rate in Post YCP enactment to total injury rate in Pre YCP enactment. Table 3. Severe Athlete-Athlete Contact Injuries Sustained During Soccer Competition in High Schools in states with and without Yellow Card Policies, National High School Sports-Related Injury Surveillance Study, USA, 2005/06-2017/18 Injury YCP# (%)b No YCP# (%) IPR (95% CI)a Concussion 247 (27.4) 945 (26.8) 1.03 (0.88,1.22) Fracture 72 (8.0) 321 (9.1) 0.87 (0.66,1.13) ACL 34 (3.8) 120 (3.4) 1.11 (0.76,1.64) Injury required surgical intervention 51 (5.7) 199 (5.7) 1.00 (0.73,1.38) Injury resulting in >3 weeks’ time lossc 124 (13.8) 581 (16.5) 0.81 (0.66, 1.00)d aInjury Proportion Ratios (IPRs). For all IPRs, No YCP is the referent category. bFor each category of injury above, % indicates what proportion of all athlete-athlete contact injuries sustained during soccer competition were accounted for by the specific injury category. cInjury resulting in >3 weeks’ time loss includes the following categories: “Returned to activity in 22 days or more,” “medical disqualification for season,” or “medical disqualification for career.” dAn upper limit of 95% CI equals 0.997, which is less than 1.00.

Youth elbow throwing injuries have been increasing among the pediatric population as more children participate in overhead sports, compete at high levels, and specialize in a single sport at an earlier age. The majority of these elbow injuries are attributable to overuse. In order to decrease the incidence of elbow injuries, recommendations and guidelines have been established and adopted by the Little League Baseball organization and other youth baseball organizations in America. There has been some success with these guidelines as they have been shown to decrease the risk of developing injury. Despite having guidelines, however, adolescents who compete in overhead sports remain at high risk of developing overuse injury, and the spectrum of injury is commonly seen in pediatric orthopedic offices. In this review, we describe six different elbow injuries associated with overuse and their specific management and treatment strategies: medial epicondyle apophysitis, medial epicondyle fracture, capitellar osteochondritis dissecans, Panner’s disease, UCL sprain, and olecranon stress injury. The purpose of this review is to highlight the spectrum of overuse elbow injuries seen in the pediatric population and briefly summarize the management of each injury.

Background: As the incidence of youth pitching injuries and surgical procedures attributed to overuse has drastically increased, there are quality concerns about popular internet resources regarding arm care for youth pitchers. Purpose/Hypothesis: To assess the medical advisability of online arm care recommendations for youth pitchers. It was hypothesized that websites contain misleading arm-care information that is discordant with medical advice. Study Design: Cross-sectional study. Methods: We reviewed the first 100 websites populated after a Google search for youth pitching recommendations. Websites were categorized by type (athletic organization, commercial, or educational) and content quality (medically advisable, discordant, or neutral), the latter with respect to the Pitch Smart guidelines used by Major League Baseball. Chi-square tests of independence and z tests of independent proportions were used to compare column proportions among categories of website content quality for each type of website source. Given the small sample sizes in some instances, the Fisher-Freeman-Halton exact test was performed to assess the relationship between website source type and quality of information. Results Of the 99 qualifying websites, 76 were categorized as medically advisable, 16 as discordant, and 7 as neutral. In addition, 92% of educational websites and 94.7% of athletic organization websites featured exclusively advisable content, whereas only 54.8% of commercial websites were advisable. Of the 16 discordant websites, 15 were commercial sites. Educational websites were significantly more advisable and neutral in content when compared with discordant information, while commercial websites were significantly predictive of discordant content. Among the first 50 websites populated according to Google, 42 (84%) were advisable, 6 (12%) discordant, and 2 (4%) neutral. The remaining websites (n = 49) featured 34 (69.4%) that were advisable, 10 (20.4%) discordant, and 5 (10.2%) neutral. Conclusion: Study findings indicated that websites of an educational nature are predictive of medically advisable content, while commercial websites (eg, blogs) are associated with discordant information. The abundance and availability of inaccurate internet information should be appreciated by medical professionals and parents/coaches of youth baseball players.

Background Improper pitching mechanics are a risk factor for arm injuries. While 3-dimensional (3D) motion analysis remains the gold standard for evaluation, most pitchers and clinicians do not have access to this costly technology. Recent advances in 2-dimensional (2D) video technology provide acceptable resolution for clinical analysis. However, no systematic assessment tools for pitching analysis exist. Purpose To determine the reliability of the Assessment of biomeChanical Efficiency System (ACES) screening tool using 2D video analysis to identify common biomechanical errors in adolescent pitchers. Study Design Cross-sectional. Methods Adolescent baseball pitchers underwent analysis using 2D video in indoor settings. Observational mechanics were collected using a 20-item scoring tool (ACES) based on 2D video analysis. Fleiss’ kappa, interclass correlation coefficients (ICC), and frequencies were used to examine intra-/interrater reliability based on common pitching errors. Results Twenty asymptomatic pitchers ages 12-18 years were included. Total ACES scores ranged from 1 to 13, normally distributed. ACES total score demonstrated excellent intra-rater reliability within each rater (ICC for rater 1 = 0.99 (95% CI; 0.98, 0.99); ICC for rater 2 = 0.94; 95% CI: 0.84, 0.97); ICC for rater 3 = 0.98 (95% CI: 0.96, 0.99)). There was excellent interrater reliability across the trials and raters (ICC = 0.91; 95% CI: 0.82, 0.96). The ACES tool demonstrated acceptable kappas for individual items and strong ICC 0.91 (95% CI: 0.82, 0.96) for total scores across the trials. Regarding identification of biomechanical errors, “front side position” was rated erroneous in 84/120 ratings (70%), stride length in 52/120 ratings (43.3%) and lead hip position in 53/120 ratings (44.2%). Conclusions The 20-item ACES scoring tool with 2D video analysis demonstrated excellent intra- and interrater reliability when utilized by raters of different musculoskeletal disciplines. Future studies validating 2D vs. 3D methodology are warranted before ACES is widely disseminated and utilized for adolescent pitchers. ACES is a practical and reliable clinical assessment tool utilizing 2D video analysis for coaches, instructors, and sports medicine providers to screen adolescent pitchers for common biomechanical errors. Level of Evidence 3b

Outpatient sports-related concussion (SRC) management continues to evolve as evidence emerges supporting a multidisciplinary approach to the clinical assessment of SRC. Early active rehabilitation has replaced strict cognitive and physical rest. With this paradigm shift in management, pragmatic approaches are highly sought by busy clinicians that provide direction to individualized treatment, which can potentially expedite symptom resolution. Treatment strategies that address domain-based symptom constellations continue to be developed by clinician researchers. Although the optimal timing and dose of these domain-specific therapies has yet to be determined, future directions of SRC treatment will answer these and other questions regarding SRC management.

BACKGROUND:The Major League Baseball (MLB) All-Star Game (ASG) Home Run Derby (HRD) remains a highly anticipated event, during which contestants can take hundreds of maximum-effort swings en route to hitting a multitude of home runs. Critics have openly questioned the risk-benefit of HRD participation as it pertains to injury, alterations in swing mechanics, and timing. PURPOSE:To determine whether participation in the MLB ASG HRD was associated with both increased injury risk and decline in second-half performance in MLB players. STUDY DESIGN:Cohort study; Level of evidence, 3. METHODS:MLB players who participated in the HRD between 2006 and 2019 were identified through publicly available internet databases. A control group of ASG participants who had the highest home run totals in the first half of the corresponding MLB season were selected as a control group. Multivariable linear regression was used to determine independent associations between HRD participation and batting metrics in the second half of the season. Multivariable logistic regression also assessed the impact of HRD participation on injured list placement during the second half of the concurrent MLB season. RESULTS:A total of 114 HRD participants and 114 ASG participant controls competed during the study period. No statistically significant differences were seen in batting metrics in the second half of the MLB season between HRD participants and ASG controls, although HRD participants had a significantly lower wins-above-replacement statistic for the season compared with controls (4.69 ± 2.06 vs 5.33 ± 2.08; P = .021). HRD participation was not significantly associated with injury during the second half. The number of HRD rounds in which a player participated did not result in a statistically significant increased odds of injury during the second half of the MLB season. CONCLUSION:HRD participants did not have increased odds of being placed on the injured list during the second half of the MLB season compared with controls, nor did they experience second-half performance declines in offensive production versus controls when multivariable linear regression analysis was performed.

Concussion remains a common injury among sports participants. Implementing risk-reduction strategies for sport-related concussion (SRC) should be a priority of medical professionals involved in the care of athletes. Over the past few decades, a multifaceted approach to reducing SRC risk has been developed. Protective equipment, rule and policy change/enforcement, educational programs, behavioral modifications, legislation, physiologic modifications, and sport culture change are a few of the programs implemented to mitigate SRC risk. In this article, the authors critically review current SRC risk-reduction strategies and offer insight into future directions of injury prevention for SRC.

In December 2019 a respiratory illness known as Coronavirus 2 (SARS-CoV-2, COVID-19) broke out in a region in China and rapidly spread to become a pandemic affecting all sporting events worldwide. The Summer Olympics scheduled to be held in Tokyo were postponed until 2021, and all professional leagues in the United States postponed or canceled events. As the United States has begun to open up, there remains uncertainty of when sporting events can safely be held. Many professional leagues and the National Collegiate Athletic Association have established guidelines and recommendations for their athletes to compete safely. In this article, we review the protocols that have been established to allow athletes to return to play, and we review briefly the effects COVID-19 infection may have on athletes.

Shoulder and elbow injuries in the adolescent population can be generally divided into skeletally immature and skeletally mature. Skeletally immature injuries refer to damage to the open growth plate (physis) in the young athlete, which have distinct differences in long-term risks if not managed correctly due to the potential for growth disturbance. Skeletally mature injuries occur in athletes with closed growth plates and are less likely to limit growth potential. It is important to recognize these different types of injuries, as well as the patients most at risk for each type because treatment may vary significantly between the two groups. The main skeletally immature injuries covered by this review will include: medial epicondyle apophysitis ("Little Leaguer's elbow), medial epicondyle fractures, olecranon stress fractures, capitellar osteochondritis dissecans (OCD), and proximal humeral apophysitis ("Little Leaguer's shoulder"). The skeletally mature injuries discussed will include: valgus extension overload syndrome (VEOS), ulnar collateral ligament (UCL) tear, shoulder instability, and superior labral anterior-posterior (SLAP) tears. We will review the history and presentation of the injuries as well as different treatment strategies and return to play guidelines for both primary care sports physicians as well as orthopedic surgeons.

OBJECTIVES:We sought to investigate the incidence and characteristics of traumatic brain injuries [mild traumatic brain injury (MTBI)] presenting to the emergency department as a result of boxing, wrestling, and martial arts (MA). DESIGN:Retrospective cross-sectional study of MTBI in combat sport athletes who were evaluated in emergency departments in the United States. SETTING:Patient data were taken from the National Electronic Injury Surveillance System. PARTICIPANTS:All patients with MTBI from 2012 to 2016, which occurred during participation in boxing, MA, or wrestling. INTERVENTIONS:None. MAIN OUTCOME MEASURES:The incidence of combat sport-related MTBI presenting to emergency departments in the United States. RESULTS:The mean annual incidence of MTBI due to wrestling was significantly larger (269.3 per 100 000 person-years) than boxing (85.6 per 100 000 person-years) and MA (61.0 per 100 000 person-years) (P < 0.01). The average age at injury was significantly lower for wrestling compared with boxing and MA (15.0 years [SD ± 3.9] vs 21.7 years [SD ± 8.2] vs 19.9 years [SD ± 10.5]; P < 0.01). A significantly larger proportion of MTBIs (95.3%; P < 0.01) in patients younger than 20 years were related to wrestling, compared with boxing (55.8%) and MA (54.1%). Most patients with combat sport-related MTBIs were treated and discharged (96.3%), with only 1.7% of patients being admitted and 0.6% of patients being held for observation. CONCLUSION:Combat sports athletes are at high risk of sustaining an MTBI. Such athletes presenting to the emergency department for combat sport-related MTBI were more likely to be male and younger than 20 years. Of these athletes, wrestlers experience the highest incidence of MTBI-related emergency department visits.