Abdominal muscle strains in professional baseball: 1991-2010

Is Workload Associated With Oblique Injuries in Professional Baseball Players?

Background

Oblique strains have become a common injury among professional baseball players. The influence of player workload on oblique strains remains unknown.

Purpose/Hypothesis

To determine whether workload is a risk factor for oblique strains in professional baseball players. We hypothesized that fewer days of rest, more innings pitched/fielded per game, and more batters faced/plate appearances per game would significantly increase a player's risk of sustaining an oblique strain.

Study Design

Case-control study; Level of evidence, 3.

Methods

All professional baseball players who sustained an oblique strain between 2011 and 2017 were identified using the Major League Baseball Health and Injury Tracking System. A separate dataset of player usage-days of rest per game, innings pitched or fielded per game, and batters faced or plate appearances per game-was used to determine the workload. We compared these usage variables between player games ≤2, ≤6, ≤12, and >12 weeks before a documented oblique strain with player games from a control group of players with no oblique strains. In a paired analysis, we compared acute (player games ≤2, ≤6, and ≤12 weeks preinjury) versus chronic (player games >12 weeks preinjury) workloads.

Results

There were 311 oblique strains in pitchers and 392 oblique strains in position players during the study period. In pitchers, more innings pitched and more batters faced were associated with a subsequent oblique strain (P < .001 for all). In position players, fewer days of rest, more innings fielded, and more plate appearances were associated with a subsequent oblique strain (P < .001 for all). Pitchers who pitched ≥7 innings per game had a 2.4-fold (95% CI, 1.4-4.9) increased risk of subsequent oblique strain compared with those who pitched 1 inning per game. The percentage of position players with a subsequent oblique strain increased by 2.1-fold (95% CI, 1.3-3.5) with >4 plate appearances compared with 1 plate appearance per game.

Conclusion

Our analysis demonstrated that workload was associated with an increased risk of sustaining an oblique injury in professional baseball players. High workload over time was more predictive of oblique strains compared to acute increases over chronic baseline workload.

The Burden of Back and Neck Strains and Sprains in Professional Baseball Players

STUDY DESIGN

A retrospective case series study.

OBJECTIVE

To analyze the epidemiology of diagnoses of back and neck strains and sprains among Major League (MLB) and Minor League (MiLB) Baseball players.

BACKGROUND

Baseball players perform unique sets of repetitive movements that may predispose to neck and back strains and sprains. Data are lacking concerning the epidemiology of these diagnoses in this population.

MATERIALS AND METHODS

De-identified data on neck/back strains and sprains were collected from all MLB and MiLB teams from 2011 to 2016 using the MLB-commissioned Health and Injury Tracking System database. Diagnosis rates of conditions related to cervical, thoracic, and lumbar musculature and their impact on days missed due to injury, player participation, and season or career-ending status were assessed. Injury rates were reported as injuries per 1000 athlete exposures (AEs).

RESULTS

There were 3447 cases of neck/back strains and sprains in professional baseball players from 2011 to 2016. Seven hundred twenty-one of these occurred in MLB versus 2726 in MiLB. Of injuries 136 were season-ending (26 in MLB, 110 in MiLB); 22 were career-ending (2 in MLB, 20 in MiLB). The total days missed were 39,118 (8838 from MLB and 30,280 from MiLB). Excluding season or career-ending injuries, the mean days missed were 11.8 (12.7 and 11.6 in MLB and MiLB, respectively). The median days missed were 4 (3 and 5 in MLB and MiLB, respectively). Combining MLB and MiLB, the pitcher injury rate was 1.893 per 1000 AEs versus 0.743 per 1000 Aes for other position players (P < 0.0001).

CONCLUSION

There was a high incidence of neck/back strains and sprains in MLB and MiLB players, with nearly 40,000 aggregate days missed in our 6-year study period. The median days missed were lower than the mean days missed, indicating rightward outliers. Pitchers had over double the rates of injuries compared with other position players.

LEVEL OF EVIDENCE

Level III.

Comprehensive Approach to Core Training in Sports Physical Therapy: Optimizing Performance and Minimizing Injuries

This clinical commentary explores the significance of a comprehensive approach to core training in sports physical therapy, focusing on optimizing performance and minimizing injuries. The core, encompassing multiple regions from the scapula to the glutes and beyond, plays a vital role in athletic performance and injury prevention. The commentary provides a thorough understanding of the various "cores" in the body, highlighting their primary functions and the importance of core stability. The commentary delves into the anatomy of the core, its primary functions, common injuries, and clinical evaluation techniques. It aims to define the role of core stability in athletic activities and discusses the prevalence and characteristics of core injuries in various sports such as baseball, basketball, football, hockey, and soccer. Furthermore, the clinical evaluation section describes subjective and objective assessments, functional testing, and special tests used to identify core injuries and determine their root causes. The author introduces a personalized dynamic core assessment to evaluate multiplanar stabilization and proposes a four-phase intervention program called the "Core Four Pyramid Principles." This program includes activation, stabilization, integration, and perturbation phases, each with specific entry criteria, goals, and targeted exercises. This commentary contributes to the body of literature by providing a comprehensive overview of core training in sports physical therapy, highlighting the significance of a systematic and evidence-based approach, and introducing the "Core Four Pyramid Principles" as a guideline for designing effective core training programs for sports therapists to optimize core function, stability and overall athletic performance while reducing the risk of injuries amongst their athletes.

Epidemiology of Lumbar Spine Conditions in Professional Baseball Players

STUDY DESIGN

A retrospective case series study.

OBJECTIVE

To analyze the epidemiology and burden of diagnoses of lumbar spinal conditions affecting Major League Baseball (MLB) and Minor League Baseball players.

SUMMARY OF BACKGROUND DATA

Lumbar spinal conditions are a common cause of low back pain in the general population and can be caused by participation in sports and athletics. Data concerning the epidemiology of these injuries in professional baseball players are limited.

METHODS

We collected deidentified MLB and Minor League Baseball data concerning lumbar spine conditions (lumbar disk herniations, lumbar degenerative disease, or pars conditions) from 2011 to 2017 using the MLB-commissioned Health and Injury Tracking System database. Data concerning days missed because of injury, need for surgery, and player participation and career-ending status were assessed. Injury rates were reported as injuries per 1000 athlete exposures in concordance with prior studies.

RESULTS

Over 2011-2017, 5948 days of play were missed because of 206 lumbar spine-related injuries, of which 60 (29.1%) were season ending. Twenty-seven (13.1%) of these injuries required surgery. The most common injury among both pitchers and position players were lumbar disk herniations (45, 44.1% and 41, 39.4%, respectively). More surgeries were performed for lumbar disk herniations and degenerative disk disease compared with pars conditions (74% and 18.5% vs. 3.7%). Injury rates for pitchers was significantly higher than those of other position players 0.111 per 1000 AEs versus 0.040 per 1000 AEs (P<0.0001). Injuries requiring surgery did not vary significantly by league, age group, or player position.

CONCLUSIONS

Lumbar spine-related injuries incurred substantial disability and days missed from play in professional baseball players. Lumbar disk herniations were the most common injury, and together with pars conditions led to higher rates of surgery compared with degenerative conditions.

LEVEL OF EVIDENCE

III.

Swinging injuries in competitive baseball players

Injuries are common in competitive baseball players and can occur in all facets of the game. The majority of the existing literature on injuries in baseball players has focused on injuries secondary to the overhead throw with very little attention given to injuries sustained while batting. The baseball swing is a complex, often violent, motion that predisposes batters to a variety of injuries affecting the spine, trunk, pelvis, and extremities. Knowledge of injury patterns that commonly occur during the baseball swing and radiologic findings important to the treating physician can help radiologists provide accurate imaging interpretations that appropriately guide patient management.

Rib Fractures in Professional Baseball Pitchers: Mechanics, Epidemiology, and Management

Pitching is a complex kinetic chain activity requiring the transfer of energy from the lower body, through the core and trunk, and finally through the arm to generate explosive acceleration of the baseball. As a result, large forces are generated in the trunk musculature and rib attachments from the late cocking phase of pitching through deceleration. The repetitive cumulative load and high pitch velocities put professional pitchers at risk of rib stress fracture. Given the potential for a prolonged recovery course and high rate of recurrence, early recognition of rib bone stress injury is critical to optimize care. Identifying torso strength imbalances, suboptimal pitching biomechanics (such as late or inadequate pelvic rotation), as well as metabolic deficiencies that may adversely affect bone health are essential to expedite safe return to play and prevent future injury. In this review, we discuss risk factors, mechanism of injury, typical clinical presentation, diagnostic imaging findings, and propose treatment and prevention strategies for rib stress fractures in overhand pitchers.

The Most Common Type, Severity, and Expected Frequency of Injuries Vary by Defensive Position in Professional Baseball Players

BACKGROUND

Location, frequency, and severity of in-game injuries by defensive position played have never been determined in professional baseball players.

HYPOTHESIS

Catchers would have a higher frequency of hip and knee injuries; infielders and outfielders would have a higher frequency of general lower extremity injuries; and pitchers would have a higher frequency and severity of shoulder and elbow/forearm injuries.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

The Major League Baseball Health and Injury Tracking System database was queried for all injuries in Major League Baseball and Minor League Baseball during the 2011-2019 seasons. Injuries were stratified by the following variables: athlete's level of play at the time of injury, anatomic region injured, whether the injury occurred during a game, and position played at the time of injury (infielder, outfielder, catcher, or pitcher). Number of days missed from competition immediately after an injury was used as a surrogate for injury severity: mild (0 days missed), moderate (1-5 days), and severe (>5 days). Observed versus expected injury ratios were calculated for each anatomic region based on position played, and ratios were adjusted by the number of players per position type during a standard inning of play.

RESULTS

A total of 112,405 work-related injuries were reported, with the majority of injuries (86,520; 77%) occurring in Minor League Baseball athletes. Injuries to the leg, hand, shoulder, torso, and foot were the most common for athletes in both leagues, while hip/groin injuries were the least common. Catchers sustained the most in-game defensive head/neck injuries, while infielders and outfielders had the highest number of knee injuries. Starting and relief pitchers had the greatest total proportion of in-game defensive injuries across every other body region. Infielders and outfielders sustained injuries less frequently than expected across all body regions, while pitchers experienced more injuries than expected for all body parts. Catchers experienced more injuries than expected to the head/neck, hand, hip/groin, knee, and foot, and were more likely than other position players to sustain a knee injury that was categorized as severe based on time missed.

CONCLUSION

The location, severity, and frequency of injuries vary by defensive position among professional baseball players.

Characteristics of internal oblique muscle strain in professional baseball players: a case series

Background

Internal oblique muscle strains can develop in professional baseball players, rendering the players unable to continue playing for a certain period. However, the characteristics of this injury are not well known. The purpose of the present study was to investigate the details of the injury and the post injury course of internal oblique muscle strain in professional baseball players.

Methods

The subjects were members of a single Japanese professional baseball team with a total of 188 players (81 fielders and 107 pitchers) who developed internal oblique muscle strains from January 2012 to December 2021. The diagnosis of muscle strain was made on the basis of local pain and magnetic resonance imaging findings. The incidence of internal oblique muscle strain, the details of the site of the injury, and the time to return to play were examined.

Results

There were 28 cases in 23 players (12.2%) of internal oblique muscle strain. The players were 16 fielders (24.7%) and 7 pitchers (7.5%), with a significantly greater incidence in fielders (p = 0.001). Although internal oblique muscle strain was more common on the side contralateral to the batting or pitching side, it occurred on either side. Most of the injury sites were at the region of the muscle insertion to the lower ribs. At a mean time of 36.5 months after the initial injury, 5 players (21.7%) developed another internal oblique muscle strain. The mean time to return to play was 27.7 ± 9.7 days (range, 4–53 days).

Conclusions

Baseball players who have symptoms at the side of the trunk should be regarded as having possible internal oblique muscle strain, and proactive examination should be considered.

The targeting rule does not increase the rate of lower extremity injuries in NFL players over two seasons

OBJECTIVES

In 2018 the NFL instituted playing rule article 8, which aimed to help decrease sport related concussion (SRC) by broadening the helmet-hit rule, making it a foul when a player lowers his head to make contact with his helmet against an opponent. Previous studies have demonstrated that the rate of lower extremity injuries increased following the institution of the targeting rule in NCAA football. The objective of this study was to determine if playing rule article 8 unintentionally led to a significant increase in the rate of lower extremity injuries sustained by NFL players during regular season games.

METHODS

This study was a retrospective review of all NFL players who were placed on the publically available injury reports for a lower extremity injury from the 2016-2017 through 2019-2020 regular seasons. With article 8 taking effect starting with the 2018-2019 season, players were assigned to a pre- or post-rule cohort based on date of injury for purposes of injury rate comparison. Injury rates were calculated per 1000 athletic exposures (AE). Incidence rate ratio (RR) with 95% confidence intervals (CI) compared injury rates between the two cohorts.

RESULTS

There was a 3% decrease in the lower extremity injury rate in 2018-2019 to 2019-2020 compared with 2016-2017 to 2017-2018, however this was not statistically significant (33.6 versus 34.3/1000 AEs, respectively; RR, 0.97; 95% CI 0.92-1.04). There was a 40% decrease in the SRC rate when comparing the post- to the pre-article-8 cohort (3.3 vs. 5.5/1000 AEs, respectively; RR 0.60; 95% CI 0.50-0.73).

CONCLUSIONS

The rate of lower extremity injuries and players placed on the injury reserve over the past two NFL seasons following the enactment of playing rule article 8 has not significantly increased. However, the average games missed due to lower extremity injuries significantly increased under playing rule article 8, which suggests that the severity of lower extremity injuries possibly increased.

LEVEL OF EVIDENCE

IV Diagnostic.

Torso dynamics during follow through in baseball batting

The purpose of this study was to clarify the relationship between the bat swing speed immediately after the ball impact and the dynamics of the torso during the follow through in baseball batting. The batting motion and ground reaction forces acting on each foot for 29 collegiate baseball players were recorded using a motion capture system and two force plates. The biomechanical variables of the torso joint (i.e., the virtual joint that divides the torso between upper and lower) were calculated. For right-handed batters, the torque power of the right rotation in the torso joint was negative. Additionally, the bat head speed immediately after the ball impact was significantly correlated with the negative (i.e., right) peak rotation torque of the torso joint (r =  -.635, p < 0.001) and the negative peak power in the right rotation torque of the torso joint (r =  -.590, p = 0.001). These results suggest that the left external abdominal oblique muscle is in eccentric contraction during the follow through in baseball batting. Moreover, the results imply that the higher the bat head speed immediately after the ball impact, the higher the possibility to strain the abdominal oblique muscle.

The Injury Rate in NBA Players Did Not Increase Following Return to Play After the COVID-19 Stay-at-Home Order

OBJECTIVE

The purpose of this study was to investigate the injury rate in NBA players following return to play during the post-COVID-19 shutdown 2019-2020 NBA season.

METHODS

This study was a retrospective review of all NBA players who were placed on the injury report during the preseason and first 4 weeks of the regular season as well as playoffs from the 2017-2018 through 2020-2021 NBA seasons. The data were compiled using publicly available injury reports. All injuries were recorded, and injury rates were calculated per 1000 athletic exposures. Risk ratio with 95% confidence intervals compared injury rates between the 2 cohorts.

RESULTS

Over the course of the study period, 399 injuries were reported. The highest injury rate per athletic exposure was observed to have occurred during the first month of the regular season in the 2 seasons prior to the COVID-19 pandemic. There was no significant difference in the average number of games missed before and after the pandemic for the preseason (P = .95), first month of regular season (P = .62), and playoffs (P = .69). There was no significant difference in the rate of injury when comparing injury rates before and after the pandemic for the preseason (P = .25), first month of the regular season (P = .11), and playoffs (P = .3).

CONCLUSION

The rate of injury in NBA players following the COVID-19 pandemic was not significantly higher than 2 recent past NBA seasons.

Side Strain and Impact Injuries at the Iliac Crest Attachment of Lateral Abdominal Wall Musculature in Cricketers: An Uncommon Injury Pattern

Side strains refer to injuries of the internal/external oblique or the transversus abdominis, commonly at their attachment to the lower four ribs and rarely at their pelvic attachments. Injuries at the rib attachments are well-described while literature on iliac crest attachment injuries is sparse. We report four cricketers who had side strain and direct impact injuries with varying degrees of severity at the iliac crest attachment. The purpose of this article is to describe the anatomy, possible mechanism of injury, and imaging findings in the lateral abdominal wall muscle injuries at the iliac crest, which have not been described previously.

Playing Rule Article Eight Decreases the Rate of Sport Related Concussion in NFL Players Over Two Seasons

OBJECTIVES

The objectives of this study were to determine if rule article 8 significantly reduced (1) the rate of concussions sustained by NFL players during regular season games, (2) the average games missed secondary to concussion injury, and (3) the number of players placed on the injury reserve for sport-related concussions (SRC).

METHODS

This study was a retrospective review of all NFL players who were placed on the publically available injury reports for a concussion from the 2016-2017 to 2019-2020 regular seasons. Player's date of injury was cross-referenced with an absence of statistics from the respective games for which they were ruled out to ensure accuracy. With article 8 taking effect starting with the 2018-2019 season, players were assigned to a pre- or postrule cohort based on date of injury for purposes of injury rate comparison. Injury rates were calculated per 1000 athletic exposures (AE). Relative risk (RR) with 95% confidence intervals (CI) compared injury rates between the two cohorts. Average number of games missed and number of players placed on injury reserve (IR) per year were also calculated. Continuous variables were statistically compared using two-tailed t-test, while categorical variables were compared using Chi-squared test. Statistical significance was set at P ≤ 0.05.

RESULTS

There was a 40% decrease in the SRC rate when comparing the post- to the pre-article-8 cohort (3.3 vs 5.5/1000 AEs, respectively; RR 0.60; 95% CI 0.50-0.73). There was no significant difference in average games missed per concussion or percentage of players placed on the IR due to SRC between the two cohorts.

CONCLUSIONS

The rate of SRC over the past two NFL seasons following the enactment of playing rule article 8 has significantly decreased when compared with the two seasons prior. The average games missed per concussion and the number of players placed on the IR due to SRC has not significantly changed under playing rule article 8.

The Injury Rate in National Football League Players Increased Following Cancellation of Preseason Games Because of COVID-19

Purpose

To investigate the injury rate in National Football League (NFL) athletes during the first 4 weeks of the 2020 NFL season.

Methods

This study was a retrospective review of all NFL players who were placed on the injury report during the preseason and the first 4 weeks of the regular season from the 2016-2017 through the 2020-2021 NFL regular seasons. Players’ dates of injury were cross-referenced with an absence of statistics from the respective games for which they were ruled out so as to ensure accuracy. Injury rates were calculated per 1,000 athletic exposures. Relative risk with 95% confidence intervals compared injury rates between the 2 cohorts.

Results

Over the course of the study period of 4 NFL seasons, 3,025 injuries were reported. Of the 3,025 injuries reported, 582 (19%) occurred during weeks 1-4 of the 2020-2021 regular season, whereas 1,292 (53%) occurred during preseason weeks 1-4, and 1,151 (38%) occurred during regular-season weeks 1-4 of NFL seasons 2016-2017, 2018-2019, and 2019-2020. There was a significant increase in the injury rate during weeks 1-4 of the 2020-2021 regular season for all comparisons with the injury rate both during the preseasons and the regular seasons of 3 recent past NFL seasons.

Conclusions

The rate of injury in NFL players during weeks 1-4 of the 2020-2021 regular seasons was significantly higher than during 3 recent past NFL preseasons and regular seasons.

Level of Evidence

Level IV, diagnostic case series.

A Systematic Review of the Orthopaedic Literature on Truncal and Lower Extremity Injuries in Major League Baseball Players

BACKGROUND

Orthopaedic injuries in Major League Baseball (MLB) players can have a tremendous impact on player health, longevity, salaries, and time lost from play.

PURPOSE

To summarize all data published between January 1980 and August 2019 on truncal and lower extremity orthopaedic injuries sustained by MLB players.

METHODS

A literature review of studies examining injuries in MLB was performed using the PubMed and Embase databases. Included studies focused on truncal and lower extremity injuries in professional baseball players. Studies pertaining to nonorthopaedic injuries, and case reports, were excluded.

RESULTS

A total of 41 articles met the inclusion criteria and were selected for the final analysis. Articles were divided based on anatomic region of injury: hip and pelvis (16%), thigh (15%), truncal (14%), knee (13%), and ankle (11%). Most studies (83.7%) were level 3 evidence. Most studies obtained data using publicly available internet resources (29.8%) compared with the MLB Health and Injury Tracking System (22.1%).

CONCLUSION

This review provides physicians with a single source of the most current literature regarding truncal and lower extremity orthopaedic injuries in MLB players. Most research was published on hip and pelvic, truncal, and thigh injuries and consisted of level III evidence.

Assessment of trunk lateral flexion range of movement using a novel method in first class cricket players

OBJECTIVES

Lateral flexion range of movement (LF ROM) is used to assess and monitor recovery of side strain injury in athletes. This study established a reliable and pragmatic measure of LF ROM and investigated the stability of the measure over time in athletes.

DESIGN

1) Cross-sectional reliability study and 2) Cohort longitudinal study.

SETTING

Elite cricket teams in COUNTRY-AAA and COUNTRY-BBB Participants: Cricket players Methods: 1) The intra- and inter-rater reliability of two methods of measuring LF ROM were assessed (distance to the floor or distance to fibular head). Ten healthy first-class cricket bowlers were tested by three experienced physiotherapists. Intra-class correlations (2,1) were calculated for absolute agreement for all 3 testers. 2) Professional cricket fast bowlers were recruited from COUNTRY-AAA and COUNTRY-BBB domestic and international competitions. Lateral flexion range of movement was measured monthly during the pre- and competitive season. A one-way repeated measures analysis of variance was performed to identify difference within the pre-season, within the competitive season, and between competitive seasons.

MAIN OUTCOME MEASURES

Lateral flexion range of movement towards and away from the bowling arm.

RESULTS

Both methods had good intra- and inter-test reliability (ICC>0.84). As LF ROM to the floor was easier for clinicians it was used for the longitudinal study. Lateral flexion range of movement did not significantly alter throughout the pre- and competitive season or between seasons (p>0.05).

CONCLUSIONS

This new method of describing LF ROM demonstrates good intra- and inter-rater reliability and stability over time and can be used as an outcome measure in side-strain injury.

Trunk Injuries in Athletes

ABSTRACT

Trunk pain is a common cause of performance limitation and time away from sport in athletes. However, atraumatic trunk injuries are underrepresented in medical literature and underrecognized clinically. Delays in diagnosis and initiation of appropriate treatment can increase injury morbidity and return-to-play time. Currently, evidence-based guidelines for diagnosis and treatment of trunk pain in athletes are limited. Thus, we provide an overview of atraumatic sport-related injuries to the thoracic spine (disc herniation, scoliosis, kyphosis), ribcage (bone stress injury, costochondritis, Tietze syndrome, slipping rib syndrome, costovertebral or costotransverse joint dysfunction), and chest and abdominal wall musculature (intercostal, serratus anterior, oblique strains, regional myofascial pain), highlighting sport-specific biomechanical considerations. We aim to increase awareness of these causes of trunk pain among sports medicine providers in an effort to guide diagnostic and treatment recommendations that will ultimately improve overall musculoskeletal health in athletes.

Frequency of overtime and consecutive games and their impact on injury rate in the National Hockey League (NHL)

OBJECTIVES

Ice hockey is a high-intensity contact sport that places athletes at an elevated risk for injury relative to other sports. The purpose of the current study was to analyze factors contributing to fatigue and decreased recovery time and their associations with injury incidence among professional athletes in the National Hockey League (NHL).

METHODS

A retrospective review of all injuries suffered by NHL athletes during six consecutive seasons from 2013 to 2019 was performed. Team schedules were analyzed to assess (1) the number of instances with games on consecutive calendar days, (2) the number of overtime games, and (3) the number of overtime games within three calendar days of a previous overtime game. A Spearman's rank correlation coefficient was calculated from this data to assess the association between these factors and injury rates.

RESULTS

In total, 4886 injuries were suffered by NHL players during the period of study, with the 2013-2014 regular season highest injury rate per 1000 athletic exposures (15.8). The lower body was the most frequently injured body area (25.0% of all injuries), followed by injuries to the upper body (23.7%). In an analysis of the number of overtime games and games on consecutive days and their relationships to injury rate, only overtime games within three calendar days and total injuries were found to have a significant association (ρ = 0.19, p = 0.01).

CONCLUSION

The weak positive correlation between the number of overtime games within threedays of a previous overtime game and total injuries in professional ice hockey players suggests that overtime games played within a short period of time place athletes at increased risk for injury. Further studies are necessary to address this on an athlete-by-athlete level.

Efficacy of Inertial Measurement Units in the Evaluation of Trunk and Hand Kinematics in Baseball Hitting

Baseball hitting is a highly dynamic activity, and advanced methods are required to accurately obtain biomechanical data. Inertial measurement units (IMUs) can capture the motion of body segments at high sampling rates both indoor and outdoor. The bat rotates around the longitudinal axis of the body; thus, trunk motion plays a key role in baseball hitting. Segmental coordination is important in transferring power to a moving ball and, therefore, useful in evaluating swing kinematics. The current study aimed to investigate the validity and reliability of IMUs with a sampling rate of 1000 Hz attached on the pelvis, thorax, and hand in assessing trunk and hand motion during baseball hitting. Results obtained using the IMU and optical motion capture system (OMCS) were compared. Angular displacements of the trunk segments and spine joint had a root mean square error of <5°. The mean absolute error of the angular velocities was ≤5%. The intra-class correlation coefficient (>0.950) had excellent reliability for trunk kinematics along the longitudinal-axis. Hand velocities at peak and impact corresponded to the values determined using the OMCS. In conclusion, IMUs with high sampling rates are effective in evaluating trunk and hand movement coordination during hitting motion.

Full-endoscopic Decompression of Foraminal Stenosis Caused by Facet Hypertrophy Contralateral to the Dominant Hand in a Baseball Pitcher: A Case Report

Back pain and lower extremity pain have various causes and occasionally occur simultaneously, creating diagnostic difficulties. In addition, athletes require special consideration in terms of treatment. Here, we report a case of foraminal stenosis as a result of lumbar disc prolapse combined with facet hypertrophy contralateral to the dominant hand in a baseball pitcher that was successfully treated by minimally invasive full-endoscopic surgery. A 31-year-old left-handed male baseball pitcher presented with complaints of low back pain and right buttock pain while pitching. A diagnosis of foraminal stenosis caused by a disc bulge combined with facet hypertrophy contralateral to the dominant hand was made on the basis of physical and radiological findings. His symptoms improved immediately after transforaminal full-endoscopic lumbar discectomy and foraminoplasty under local anesthesia. He returned to play 3 months after surgery. Foraminal stenosis due to facet hypertrophy may occur in the side contralateral to the throwing arm in pitchers. Minimally invasive decompression using a full-endoscopic procedure is required for high-level athletes at this position.

Does the MLB's collision at home plate rule change prevent concussion injuries in catchers?

Background: In 2013, appropriate conduct of both the catcher and baserunner at the home plate was outlined with the addition of rule 7.13. This new rule was mandated in order to protect athletes from 'egregious' collisions at the home plate. The aims of this study were to quantify the impact of the Collision at Home Plate rule on concussion rates among MLB catchers, and time spent on the DL with concussion symptoms, before and after rule 7.13 was officially enacted (2012-2013, 2015-2016). Hypothesis: We hypothesized that the rate of concussions suffered by MLB catchers would be significantly lower after the enactment of rule 7.13 and that there would be no significant difference in time spent on the DL between the two cohorts. Study design: Retrospective Cohort Level of evidence: Level 3 Methods: The data was compiled using publicly available information extracted from MLB transactions. All MLB catchers placed on the DL for a concussion injury from 2012 to 2013 and 2015 to 2016 were included in this study. Relative risk (with 95% CI) was calculated by using the number of injuries per 1,0000 athletic exposures for the 2 seasons under the rule change (2015-2016) versus the previous 2 seasons (2012-2013). Results: Among catchers the relative risk of concussion per 1000 athletic exposures was 0.31 (95% CI, 0.11-0.85) when comparing the 2 seasons after the introduction of rule 7.13 (2015, 2016) versus the 2 seasons before (2012, 2013). There was no significant statistical difference in average time catchers spent on the DL for concussion injuries when comparing the 2012 and 2013 seasons versus 2015 and 2016. Conclusions: The MLB's rule limiting home plate collisions significantly reduced the number of concussions suffered by MLB catchers. Clinical relevance: This study provides important insight regarding patterns and injury rates in professional baseball catchers and can serve as a benchmark for discussion about injury prevention in players of this position. To our knowledge, no other study has focused on rule 7.13 and its effect on concussion rates in MLB catchers.

Changes in lumbar kinematics and trunk muscle electromyographic activity during baseball batting under psychological pressure

Psychological pressure during sports competition disturbs the ideal physical movement and causes injury. Baseball batting frequently causes trunk injuries. This study aimed to examine the influence of psychological pressure on the lumbar kinematics and trunk muscle activity during the baseball batting. Fourteen collegiate baseball players participated in this study. The participants performed bat swings under three different psychological conditions (non-pressure, pressure, and emphasized pressure). The lumbar kinematics and trunk muscle activity were measured during each bat swing. One- and two-way analyses of variance were performed to compare the lumbar kinematics and trunk muscle activity among different psychological pressure conditions. The lumbar flexion angle throughout the bat swing in the swing phase, from the moment of ground contact of the lead foot to the moment of ball contact, was significantly larger under the pressure and emphasized pressure conditions than under the non-pressure condition (P<0.05). The bilateral lumbar erector spinae (LES) activities in the swing and follow-through phases were significantly higher under the emphasized pressure condition than under the non-pressure condition (P<0.05). These results indicate that the baseball batting under psychological pressure influenced the lumbar kinematics and bilateral LES activities and may be related to the development of low back pain.

Injury in the Women's National Basketball Association (WNBA) From 2015 to 2019

Purpose

To provide an overview of the injuries suffered by Women’s National Basketball Association (WNBA) athletes and to analyze the demographic data, injury rates, and games missed as a result of individual injuries.

Methods

Using publicly available data on WNBA player’s injury history, we generated a database cataloguing the quantity, location, frequency, and longitudinal impact of injuries sustained during the WNBA regular season from 2015 to 2019. We analyzed the data using SPSS-25 data manipulation software to assess the number of injuries per athletic exposure.

Results

Lower-extremity injuries (n = 143, 73%) were the most common injury by body area and resulted in the greatest number of games missed (n = 1189, 88%). Lateral ankle sprains were the most frequent injury (n = 39, 20%), with a rate of 1.19 injuries per 1000 athletic exposures. Torn anterior cruciate ligaments (n = 18, 9.2%) were the most devastating, resulting in the greatest number of games missed (n=376, 28%).

Conclusions

Our findings corroborate previous notions that lower-extremity injuries are the greatest source of injury in this population. Ankle injuries were the most frequent injury reported by pathology, while knee injuries carried the most long-term impact on games missed due to injury.

Level of Evidence

IV, Epidemiological study

Abdominal wall sonography: a pictorial review

The anterior abdominal wall, which is composed of three layers (skin and adipose tissues; the myofascial layer; and the deep layer, consisting of the transversalis fascia, preperitoneal fat, and the parietal peritoneum), has many functions: containment, support and protection for the intraperitoneal contents, and involvement in movement and breathing. While hernias are often encountered and well reviewed in the literature, the other abdominal wall pathologies are less commonly described. In this pictorial review, we briefly discuss the normal anatomy of the anterior abdominal wall, describe the normal ultrasonographic anatomy, and present a wide range of pathologic abnormalities beyond hernias. Sonography emerges as the diagnostic imaging of first choice for assessing abdominal wall disorders, thus representing a valuable tool for ensuring appropriate management and limiting functional impairment.

Abdominal oblique muscle injury at its junction with the thoracolumbar fascia in a high school baseball player presenting with unilateral low back pain

Abdominal oblique muscle injury is characterized by acute pain and localized tenderness over the lateral trunk. This injury is particularly common among throwing athletes, and usually presents as anterolateral abdominal wall pain. Imaging evidence is scarce in regard to whether oblique muscle injury at its junction with the thoracolumbar fascia can instead present with low back pain. A high school baseball player with unilateral low back pain was referred to us with a different diagnosis.　Careful palpation and magnetic resonance imaging guided our care, and the patient returned to high-level competition after 7 weeks of conservative treatment, with no report of recurrence in the subsequent 12 months. Oblique muscle injury at its junction with the thoracolumbar fascia should be added to the differential diagnosis for throwing athletes with unilateral low back pain following a torque movement.

MRI findings are associated with time to return to play in first class cricket fast bowlers with side strain in Australia and England

OBJECTIVES

To investigate the reliability of reporting and relationship between MRI parameters at injury and time to return to play (RTP) in first class cricket fast bowlers with side strain in Australia and England.

DESIGN

Cohort study.

METHODS

Eighty MRI scans of side strain injuries to 57 fast bowlers were sourced. Ten scans were reported by three experienced radiologists to determine intra- and inter-rater reliability. The relationship between six MRI parameters (muscle injured, presence of a muscle tear, rib level of injury, presence of blood fluid products/haematoma, periosteal stripping, rib oedema) and time to RTP was investigated with 39 scans reported by a single radiologist with known intra-rater reliability. The association between parameters and time to RTP was analysed with an ordinal logistic regression model.

RESULTS

Recovery time was prolonged with a mean of 39days (standard deviation: 14days) and 44% of bowlers requiring more than 6weeks to RTP. Reliability levels between parameters varied widely. The presence or absence of a muscle tear was the only MRI parameter associated with time to RTP. Players with a muscle tear were 8 times more likely to take more than 6weeks to RTP. The multifactorial model was predictive of recovery time in only 53% of this cohort, leaving 47% of total variance in time to RTP unexplained.

CONCLUSIONS

The presence of a muscle tear was associated with time to RTP in cricket fast bowlers with side strain injury in first class cricket in Australia and England.

Knee pain is associated with lower back pain in young baseball players: a cross-sectional study

PURPOSE

Considerable research has focused on shoulder and elbow injuries among baseball players; however, although lumbar spine and knee injuries are commonly experienced, they are less frequently studied. During common motions in baseball, such as throwing, hitting, and running, energy is transferred from the lower extremities through the lower back to the upper body. Lower extremity pain, as well as lower back pain (LBP), can disrupt the kinematic chain, and it is important to understand the association between lower extremity complaints and LBP. The purpose of this study was to elucidate the association between knee pain and LBP among young baseball players.

METHODS

A cross-sectional study was conducted with young baseball players (aged 6-15 years, n = 1,609) using a self-reported questionnaire. Multivariate logistic regression models were used for analyses. Variables considered in the models were sex, age, body mass index, team levels, number of days of training per week, number of hours in practice per day on weekdays and weekend, frequency of participation in games, practice intensity, and player position.

RESULTS

The point prevalence of LBP and knee pain was 8.4% and 13.1%, respectively. Knee pain was significantly associated with LBP. Using the absence of knee pain as a reference, the adjusted odds ratio (95% confidence interval) for LBP was 5.83 (3.93-8.65) (p < 0.001) in the presence of knee pain.

CONCLUSIONS

Knee pain was associated with LBP among young baseball players. Clinicians should pay attention to knee complaints to prevent and treat LBP among young baseball players.

LEVEL OF EVIDENCE

III.

Forearm Flexor Injuries Among Major League Baseball Players: Epidemiology, Performance, and Associated Injuries

BACKGROUND

Despite evidence highlighting the importance of the forearm flexor muscles of elite baseball players, no studies have reported on the epidemiology of flexor strains and their associated outcomes.

PURPOSE

To examine the incidence, associated injuries, and outcomes associated with forearm flexor injuries among major and minor league baseball players.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Injury data attributed to forearm flexor injuries among Major League Baseball (MLB) and minor league teams between 2010 and 2014 were obtained from the professional baseball Health and Injury Tracking System. This analysis included the number of players injured, seasonal timing of injury, days spent on the disabled list (DL), preinjury performance data, and subsequent injuries.

RESULTS

A total of 134 and 629 forearm flexor injuries occurred in MLB and the minor leagues, respectively. The mean player age was 28.6 and 22.8 years in the MLB and minor leagues, respectively. The mean time spent on the DL for MLB players was 117.0 days, as opposed to 93.9 days in the minor leagues ( P = .272). Interestingly, pitcher performance declined in all categories examined leading up to the season of injury, with significant differences in walks plus hits per inning pitched ( P = .04) and strike percentage ( P = .036). Of MLB players with a forearm injury, subsequent injuries included 50 (37.3%) shoulder, 48 (35.8%) elbow, and 24 (17.9%) forearm injuries. Among injured minor league players, subsequent injuries included 170 (27.0%) shoulder, 156 (24.8%) elbow, and 83 (13.2%) forearm injuries. These rates of subsequent injuries were significantly higher compared with the rates of injuries sustained among players without forearm injuries in both leagues ( P < .001). Finally, 26 (19.4%) MLB and 56 (8.9%) minor league players required an ulnar collateral ligament reconstruction, rates that were significantly higher compared with players without a flexor strain ( P < .001).

CONCLUSION

Flexor-pronator injuries are responsible for considerable time spent on the DL for elite players in MLB and the minor leagues. The most significant findings of this investigation illustrate that a flexor strain may be a significant risk factor for subsequent upper extremity injuries, including an ulnar collateral ligament tear.

Trunk Side Strain Has a High Incidence in First-Class Cricket Fast Bowlers in Australia and England

OBJECTIVE

To investigate the past incidence of side strain injury and its associated factors in first-class cricket fast bowlers in Australia and England.

DESIGN

Retrospective case series.

SETTING

Professional cricket.

PARTICIPANTS

Cricket fast bowlers who were professionally contracted full time at first-class level in Australia and England in 2011. All bowlers were male and aged 18 or older. A bowler was defined as a fast bowler if the wicketkeeper would take their stance back from the stumps. There were 207 participants.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The association between bowling arm, player height, active trunk lateral flexion range of motion, side bridge endurance, volume of first-class cricket played, and the history of injury was determined.

RESULTS

Over half of the bowlers had sustained at least 1 side strain in their career. Seventy-seven percent of primary injuries occurred in bowlers aged 24 or under. A higher proportion of injured bowlers had reached first-class volume in their career. Recurrence occurred in 30% of bowlers, with over 30% of these bowlers sustaining at least 1 further recurrence. Nearly half of all recurrences occurred within 2 years with a further quarter in the next year. The injury was not associated with any measured factors.

CONCLUSIONS

Side strain is a common injury among first-class cricket fast bowlers, especially at younger ages. It was associated with the volume of first-class cricket played. Recurrence was common and occurred most frequently in the first 2 years after primary injury.

Epidemiology, Workload, and Performance of Major League Baseball Pitchers Placed on the Disabled List

There is limited information on the effect of pitcher workload, pitch type, and performance of Major League Baseball pitchers placed on the disabled list (DL). This study evaluated demographic, performance, workload, and injury data of 330 Major League Baseball pitchers with 454 injuries who were placed on the DL during the 2014 and 2015 seasons. Upper extremity, lower extremity, core, hip/groin, and other injuries were analyzed, and injury year data were compared with career data as well as against other injury groups. Upper extremity injuries represented 60% of injuries and a mean of 61.4 (SE, 2.6) days on the DL, while lower extremity and core injuries each represented 14% of all injuries. Players with upper extremity injuries returned to play the same season at the lowest rate (67.3%). Starters pitched more mean innings per game (5.31 vs 5.14 innings, P=.012) and threw more mean pitches per game (85.9 vs 82.4 pitches, P=.003) the year of injury compared with their career. There was a decrease in mean fastball velocity (92.2 vs 91.6 mph, P<.001) and percentage of fastballs thrown (60.3% vs 58.5%, P<.001) the year of injury for all injuries. The authors found that upper extremity injuries are the most common, require the most time on the DL, and have the lowest same season return to play rate. Starters pitched significantly more innings and threw more pitches during the year of injury. Pitchers were found to have a decrease in fastball velocity and percentage of fastballs thrown during the year of injury. [Orthopedics. 2018; 41(3):178-183.].

Implications of Core and Hip Injuries on Major League Baseball Pitchers on the Disabled List

PURPOSE

To investigate the frequency of core and hip injuries in Major League Baseball (MLB) pitchers and their impact on performance, workload, and pitch type.

METHODS

Demographic, performance data, and injury data were acquired for 330 MLB pitchers with 454 injuries placed on the disabled list (DL) from 2014 to 2015 seasons. Core and hip/groin injuries were analyzed in which injury year data were compared with career data and against other injury groups.

RESULTS

Core injuries represented 14% of all injuries and hip/groin injuries represented 7%. Average days on the DL for core injuries were 47.0 (standard deviation 5.6) days and 37.7 (standard deviation 8.1) days for hip/groin injuries. Return from the DL the same season for core injuries was 78% and 73% for hip/groin injuries. Core injuries returned to the DL 46% of the time (73% for noncore injuries) and hip/groin returned 56% of the time (60% for nonhip/groin injuries). No changes in workload were noted except starters with core injuries pitched less innings/game (5.3 vs 4.9 innings/game, P = .031) and more pitches/game (85.5 vs 78.4 pitches, P = .026). Fastball velocity decreased in the core injury group the year of injury (91.6 vs 92.2 mph, P = .001). Core injuries had slightly fewer home runs/9 innings and fewer strikeouts/9 innings; hip/groin injuries had slightly more strikeouts/9 innings, with all other performance statistics no different between the groups including earned run average and wins above replacement.

CONCLUSIONS

Core and hip injuries in MLB pitchers result in similar time on the DL compared with other injuries. Pitching workload during the year of injury does not seem to have a significant impact on sustaining a core or hip injury. Although there is a high rate of return to play from the DL, there is a high rate of reinjury in these pitchers more often for other injuries.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Are Passive Physical Modalities Effective for the Management of Common Soft Tissue Injuries of the Elbow?: A Systematic Review by the Ontario Protocol for Traffic Injury Management (OPTIMa) Collaboration

OBJECTIVE

To evaluate the effectiveness of passive physical modalities for the management of soft tissue injuries of the elbow.

METHODS

We systematically searched MEDLINE, EMBASE, CINAHL, PsycINFO, and Cochrane Central Register of Controlled Trials from 1990 to 2015. Studies meeting our selection criteria were eligible for critical appraisal. Random pairs of independent reviewers critically appraised eligible studies using the Scottish Intercollegiate Guidelines Network criteria. We included studies with a low risk of bias in our best evidence synthesis.

RESULTS

We screened 6618 articles; 21 were eligible for critical appraisal and 9 (reporting on 8 randomized controlled trials) had a low risk of bias. All randomized controlled trials with a low risk of bias focused on lateral epicondylitis. We found that adding transcutaneous electrical nerve stimulation to primary care does not improve the outcome of patients with lateral epicondylitis. We found inconclusive evidence for the effectiveness of: (1) an elbow brace for managing lateral epicondylitis of variable duration; and (2) shockwave therapy or low-level laser therapy for persistent lateral epicondylitis.

DISCUSSION

Our review suggests that transcutaneous electrical nerve stimulation provides no added benefit to patients with lateral epicondylitis. The effectiveness of an elbow brace, shockwave therapy, or low-level laser therapy for the treatment of lateral epicondylitis is inconclusive. We found little evidence to inform the use of passive physical modalities for the management of elbow soft tissue injuries.

Cluster randomised control trial for cricket injury prevention programme (CIPP): a protocol paper

Background

Injury prevention programmes (IPPs) are effective in reducing injuries among adolescent team sports. However, there is no validated cricket-specific IPP despite the high incidence of musculoskeletal injuries among amateur cricketers.

Objectives

To evaluate whether a cricket injury prevention programme (CIPP) as a pretraining warm-up or post-training cool-down can reduce injury rates in amateur cricket players.

Methods

CIPP is a cluster randomised controlled trial which includes 36 male amateur club teams having cricket players aged 14–40 years to be randomly assigned to three study arms: warm-up, cool-down and control (n=12 teams, 136 players in each arm). The intervention groups will perform 15 min CIPP either as a pretraining warm-up or a post-training cool-down.

Outcome measures

The primary outcome measure will be injury incidence per 1000 player hours and the secondary outcome measures will be whether IPP as a warm-up is better than IPP as a cool-down, and the adherence to the intervention.

Trial registration number

ACTRN 1261700047039.

Epidemiology and Impact of Abdominal Oblique Injuries in Major and Minor League Baseball

Background:

Oblique injuries are known to be a common cause of time out of play for professional baseball players, and prior work has suggested that injury rates may be on the rise in Major League Baseball (MLB).

Purpose:

To better understand the current incidence of oblique injuries, determine their impact based on time out of play, and to identify common injury patterns that may guide future injury prevention programs.

Study Design:

Descriptive epidemiological study.

Methods:

Using the MLB Health and Injury Tracking System, all oblique injuries that resulted in time out of play in MLB and Minor League Baseball (MiLB) during the 2011 to 2015 seasons were identified. Player demographics such as age, position/role, and handedness were included. Injury-specific factors analyzed included the following: date of injury, timing during season, days missed, mechanism, side, treatment, and reinjury status.

Results:

A total of 996 oblique injuries occurred in 259 (26%) MLB and 737 (74%) MiLB players. Although the injury rate was steady in MiLB, the MLB injury rate declined (P = .037). A total of 22,064 days were missed at a mean rate of 4413 days per season and 22.2 days per injury. The majority of these occurred during batting (n = 455, 46%) or pitching (n = 348, 35%), with pitchers losing 5 days more per injury than batters (P < .001). The leading side was injured in 77% of cases and took 5 days longer to recover from than trailing side injuries (P = .009). Seventy-nine (7.9%) players received either a corticosteroid or platelet-rich plasma injection, and the mean recovery time was 11 days longer compared with those who did not receive an injection (P < .001).

Conclusion:

Although the rate of abdominal oblique injuries is on the decline in MLB, this is not the case for MiLB, and these injuries continue to represent a significant source of time out of play in professional baseball. The vast majority of injuries occur on the lead side, and these injuries result in the greatest amount time out of play. The benefit of injections for the treatment of oblique injuries remains unknown.

Applicability of ultrasonography for evaluating trunk muscle size: a pilot study

[Purpose] Ultrasonography (US) is widely applied to measure the muscle size in the limbs, as it has relatively high portability and is associated with low costs compared with large clinical devices such as magnetic resonance imaging (MRI). However, the applicability of US for evaluating trunk muscle size is poorly understood. This study aimed to examine whether US-measured muscle thickness (MT) in the trunk abdominal and back muscles correlated with MT and muscle cross-sectional area (MCSA) measured by MRI. [Subjects and Methods] Twenty-four healthy young males participated in this study. The MT and MCSA in the subjects were measured by US and MRI in a total of 10 sites, including the bilateral sides of the rectus abdominis (upper, central, and lower parts), abdominal wall, and multifidus lumborum. [Results] The interclass correlation coefficients of US-measured MT on the total 10 sites showed excellent values (n=12, 0.919 to 0.970). The US-measured MT significantly correlated with the MRI-measured MT (r=0.753 to 0.963) and MCSA (r=0.634 to 0.821). [Conclusion] US-measured MT could represent a surrogate for muscle size measured by MRI. The application of US for evaluating trunk muscle size may be a useful tool in the clinical setting.

Assessment and rehabilitation of chronic low back pain in baseball: part II

Repetitive throwing and hitting motions in baseball place mechanical stresses to the lumbar spine which may cause low back pain (LBP). Pain may be due to vertebral stress reactions or insufficiency fractures, intervertebral disc degeneration or intervertebral disc herniation. Untreated chronic conditions have high potential to lead to a more significant injury such as spondylolysis. Chronic LBP increases the risk for missed playing time, early career termination and lower quality of life after retirement. Proper clinical assessment and prevention/rehabilitation of LBP in this population is thus important for performance, play time and overall long-term quality of life. This narrative review synopsizes the available evidence for assessment and rehabilitation of baseball players with LBP, including the structured rehabilitative techniques and programmes which should be administered to affected players. The state of the evidence suggests that there are deficits in identifying the optimal prevention and rehabilitation prescription components for the variety of LBP-inducing injuries in this athletic population.

The pyramidalis-anterior pubic ligament-adductor longus complex (PLAC) and its role with adductor injuries: a new anatomical concept

PURPOSE

Adductor longus injuries are complex. The conflict between views in the recent literature and various nineteenth-century anatomy books regarding symphyseal and perisymphyseal anatomy can lead to difficulties in MRI interpretation and treatment decisions. The aim of the study is to systematically investigate the pyramidalis muscle and its anatomical connections with adductor longus and rectus abdominis, to elucidate injury patterns occurring with adductor avulsions.

METHODS

A layered dissection of the soft tissues of the anterior symphyseal area was performed on seven fresh-frozen male cadavers. The dimensions of the pyramidalis muscle were measured and anatomical connections with adductor longus, rectus abdominis and aponeuroses examined.

RESULTS

The pyramidalis is the only abdominal muscle anterior to the pubic bone and was found bilaterally in all specimens. It arises from the pubic crest and anterior pubic ligament and attaches to the linea alba on the medial border. The proximal adductor longus attaches to the pubic crest and anterior pubic ligament. The anterior pubic ligament is also a fascial anchor point connecting the lower anterior abdominal aponeurosis and fascia lata. The rectus abdominis, however, is not attached to the adductor longus; its lateral tendon attaches to the cranial border of the pubis; and its slender internal tendon attaches inferiorly to the symphysis with fascia lata and gracilis.

CONCLUSION

The study demonstrates a strong direct connection between the pyramidalis muscle and adductor longus tendon via the anterior pubic ligament, and it introduces the new anatomical concept of the pyramidalis-anterior pubic ligament-adductor longus complex (PLAC). Knowledge of these anatomical relationships should be employed to aid in image interpretation and treatment planning with proximal adductor avulsions. In particular, MRI imaging should be employed for all proximal adductor longus avulsions to assess the integrity of the PLAC.

Lower thoracic rib stress fractures in baseball pitchers

Stress fractures of the first rib on the dominant throwing side are well-described in baseball pitchers; however, lower thoracic rib fractures are not commonly recognized. While common in other sports such as rowing, there is scant literature on these injuries in baseball. Intercostal muscle strains are commonly diagnosed in baseball pitchers and have a nearly identical presentation but also a highly variable healing time. The diagnosis of a rib stress fracture can predict a more protracted recovery. This case series presents two collegiate baseball pitchers on one team during the same season who were originally diagnosed with intercostal muscle strains, which following magnetic resonance imaging (MRI) were found to have actually sustained lower thoracic rib stress fractures. The first sustained a stress fracture of the posterior aspect of the right 8th rib on the dominant arm side, while the second presented with a left-sided 10th rib stress fracture on the nondominant arm side. In both cases, MRI was used to visualize the fractures as plain radiographs are insensitive and commonly negative early in patient presentation. Patients were treated with activity modification, and symptomatic management for 4-6 weeks with a graduated return to throwing and competition by 8-10 weeks. The repetitive high stresses incurred by pitching may cause either dominant or nondominant rib stress fractures and this should be included in the differential diagnosis of thoracic injuries in throwers. It is especially important that athletic trainers and team physicians consider this diagnosis, as rib fractures may have a protracted course and delayed return to play. Additionally, using the appropriate imaging techniques to establish an accurate diagnosis can help inform return-to-play decisions, which have important practical applications in baseball, such as roster management and eligibility.

Side strain in sport: a narrative review of pathomechanics, diagnosis, imaging and management for the clinician

OBJECTIVES

To provide an overview of the published literature on epidemiology, pathomechanics and risk factors for side strain injury in sport, complemented by clinical perspectives of diagnosis and management strategies that are not covered in the literature.

DESIGN

Narrative review METHODS: A review of the literature was completed with all studies on side strain up until October 2015 included. As the studies were unable to be synthesised the findings were placed in a clinical context. As there were no papers on the management of side strain a clinical perspective from cricket was included.

RESULTS

Literature on side strain in sport is sparse with only nine papers dedicated to the injury. These comprise epidemiology, case studies, small case series and clinical reviews on imaging, injection and surgery. The epidemiology demonstrates that side strain is most commonly associated with cricket and baseball. Side strain typically occurs acutely mostly on the side contralateral to the dominant arm in athletes. Diagnosis is clinical with consistent imaging features that typically demonstrate a tear of the internal oblique from the lower ribs. Recovery periods can be prolonged and recurrence may occur. There has been no research on the management of side strain and the relationship between clinical assessment and imaging findings and time to return to play or risk of recurrence.

CONCLUSIONS

Side strain injury is prevalent in cricket and baseball. Recovery is extended and recurrence may occur. Incidence appears to be increasing. Knowledge on side strain is limited.

Unusual chest wall pain caused by thoracic disc herniation in a professional baseball pitcher

Symptomatic thoracic disc herniation is clinically rare.　There are few cases of disc herniation of the thoracic spine in top athletes described in the literature.　We herein present a rare case of chest wall pain due to thoracic disc herniation in a professional baseball pitcher.　A 30-year-old, left-handed pitcher complained of left-sided chest wall pain in the region of his lower ribs during a game. Neurological examination revealed hypoesthesia of the left side of the chest at the level of the lower thoracic spine.　Magnetic resonance imaging (MRI) of the thoracic spine showed a left-sided paramedian disc herniation at the T9-T10 level.　The player was initially prescribed rest, administration of pregabalin (150 mg twice a day), and subsequent physical rehabilitation.　He was able to resume full training and pitching without medication 6 months after the onset.　A follow-up MRI of the thoracic spine showed a reduction in the size of the herniated disc compared to the initial findings.　Though relatively rare, thoracic disc herniation should be considered in cases of chest wall pain in athletes.

Epidemiology of Injuries in Major League Baseball Catchers

BACKGROUND

In part because of the perception that many injuries occur during collisions with the catcher at home plate, Major League Baseball (MLB) officials recently implemented rule changes to prevent these injuries. There is little research on the rate, type, and severity of injuries in MLB catchers.

PURPOSE

To (1) determine the types and severity of injuries to catchers, (2) determine catchers' athlete exposure (AE) rate of injuries, and (3) assess the perception that catchers are at risk for career-ending injuries caused by home plate collisions.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

The MLB Electronic Baseball Information System was queried for injuries in catchers during the 2001-2010 seasons categorized by cause (collision vs noncollision), diagnosis, and severity. All collision injuries were confirmed by reviewing publicly accessible records and news media. The injury exposure rate per 1000 AEs was calculated, and the rate of injury, associated days on the disabled list (DL), and injury severity were determined on the basis of cause and location of injury. Poisson regression was used to compare rates among seasons, and significance was set at P < .05.

RESULTS

During the study period, 134 injuries were sustained, resulting in 6801 days lost. The mean time on the DL was 50.8 days (range, 15-236). The average injury rate was 2.75 injuries per 1000 AEs (range, 0.82-5.14). Of those 134 injuries, 20 were collision injuries. Collision injuries resulted in a mean of 39 days (range, 15-93) of DL time, compared with 53 days for noncollision injuries (range, 15-236), which was not a significant difference. No collision injury was career ending. Noncollision injuries more commonly resulted in >100 days on the DL compared with collision injuries (P = .049).

CONCLUSION

Study findings indicated that (1) the most common type of injury to catchers was noncollision injury, (2) the rate of injuries to catchers is lower than previously reported rates for other player positions, and (3) this study did not support the perception that collision injuries are a frequent cause of career-ending injury to catchers.

Return to competition, re-injury, and impact on performance of preseason shoulder injuries in Major League Baseball pitchers

OBJECTIVE

Major league baseball (MLB) pitchers are vulnerable to overuse injury of the upper extremity, especially in the shoulder. Injuries sustained in the preseason may have negative impact on performance following return. The goal of this study was to document the frequency of preseason shoulder injury in these athletes, as well as risk for re-injury and impact on performance following return from injury.

METHODS

A comprehensive search of MLB injury information from 2001 to 2010 of public databases yielded a cohort of MLB pitchers who sustained preseason shoulder injuries. These databases were utilized to obtain information regarding return to MLB competition, re-injury, and performance following return from injury. All performance metrics were compared to those of an age-matched control cohort.

RESULTS

A total of 74 pitchers were identified who sustained a preseason shoulder injury. Only 39 (53%) returned that same season to pitch in the MLB competition. Of those that returned, nearly 50% of players were re-designated on the Disabled List during the return season. There was a decline in performance in earned run average and batting average against in the year of return. Compared to age-matched control pitchers, those with preseason shoulder injury had lower performance metrics across a number of outcomes.

CONCLUSION

Preseason shoulder injury in MLB pitchers has the potential to result in high re-injury rates and decreased subsequent performance.