Risk factors for shoulder and elbow pain in youth baseball players

Risk factors and prevention strategies for shoulder injuries in overhead sports: an updated systematic review

PURPOSE

The aim of this systematic review was to update the knowledge on risk factors and prevention strategies for shoulder injuries in overhead sports with special emphasis on methodological quality.

METHODS

All methodological procedures were performed in line with a previous systematic review by Asker et al. (2018). The literature search was conducted in the PubMed, Google Scholar, Cochrane, and SPORT-Discuss databases. Due to the risk of bias assessment, only studies with at least an acceptable methodological quality were included. A best-evidence synthesis was performed to clarify the evidence and direction of the risk factors and prevention strategies.

RESULTS

A total of nine studies were included in the data extraction process. One study had a high and eight studies had an acceptable methodological quality. Seven cohort studies investigated risk factors and two randomised controlled trails evaluated prevention strategies. Moderate evidence was found for two non-modifiable (playing position, gender) and three modifiable factors (shoulder rotational strength, scapular dyskinesia, shoulder prevention programme) that were associated with the shoulder injury risk. All further risk factors had moderate and no association with risk (shoulder rotational ROM, joint position sense) or limited (history of shoulder/elbow pain, age, training experience, training volume, school grade, playing level), and conflicting evidence (setting).

CONCLUSIONS

There is moderate evidence for two non-modifiable (playing position, gender) and three modifiable factors (shoulder rotational strength, scapular dyskinesia, shoulder prevention programme) being associated with the shoulder injury risk in overhead sports.

Lifestyle Changes and Baseball Activity among Youth Baseball Players before and during the First COVID-19 Pandemic in Japan

This cross-sectional study aimed to clarify the changes in lifestyle and baseball activity before and during the COVID-19 pandemic among youth baseball players. Participants were 99 youth baseball players (ages 9.6 ± 1.5 years, height 137.8 ± 9.4 cm, weight 35.3 ± 12.4 kg) in Japan. They completed an online survey between April 6 and 20, 2021, on their demographic characteristics, lifestyle (recreational screen, sleep, and study times), and baseball activity (frequency of team practice time and voluntary exercise-related baseball) at two-time points: before the pandemic (before March 2020) and during the state of emergency declared in Japan (from April to May 2020). The changes in outcomes between the two-time points were evaluated for significance. Recreational screen time and sleeping time during the state of emergency were significantly increased compared to those before the pandemic (p < 0.001). The frequency of team practice time on weekends during the state of emergency was significantly reduced, and voluntary exercise-related baseball was significantly increased compared to that before the pandemic (p < 0.01). We found that the COVID-19 pandemic changed behaviors concerning activities and exercise among youth baseball players and recommended that such behavioral changes be carefully monitored.

Increased medial laxity of the elbow in preadolescent baseball players with or without medial elbow apophysitis

Background

Medial elbow apophysitis is a traction apophysitis observed in the medial epicondyle of the elbow in preadolescent baseball players. The purpose of this study was to determine the relationship between medial elbow apophysitis and elbow valgus instability in preadolescent baseball players.

Methods

The participants were classified into a control group and an injury group; the injury group included participants diagnosed with a medial elbow injury (inclusion criteria were only symptoms of the elbow joint or positive findings on physical examinations, or both). Elbow valgus instability was assessed by measuring the differences in ulnohumeral joint gapping width, with and without gravity stress induced by weight loading of the forearm using ultrasonography.

Results

The control and injury groups consisted of 81 and 23 preadolescent baseball players, respectively. In the throwing elbow, valgus instability in the injury group was significantly greater than that in the control group (1.07 vs. 0.57 mm, P = .001). In the non-throwing elbow, valgus instability in the injury group was significantly greater than that in the control group (0.57 vs. 0.37 mm, P = .011). The area under the curve for valgus instability of the throwing elbow was 0.89 mm (95% confidence interval, 0.64-0.77), and the cut-off value for elbow pain appearance was 0.80 mm.

Conclusion

The increased elbow valgus instability in the injury group was associated with a medial elbow injury. For the elbow valgus instability of the non-throwing side in the injury group, we considered that players with medial elbow apophysitis inherently have elbow laxity.

Risk Factors for Throwing-Related Shoulder and Elbow Pain in Adolescent Baseball Players: A Prospective Study of Physical and Developmental Factors

Background:

Throwing-related shoulder and elbow pain continues to be reported among adolescent baseball players. Few prospective studies have specifically examined the association between throwing-related shoulder and elbow pain and physical and developmental changes.

Purpose:

To evaluate the changes in physical and developmental characteristics during 1 year with respect to throwing-related shoulder and elbow pain in adolescent baseball players.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

This 1-year prospective follow-up study investigated 164 baseball players aged 7 to 13 years. Player data (age, height, weight, field position, and pitch count), lower extremity muscle tightness, and range of motion (ROM) of the shoulder, elbow, and hip joints were assessed during the 2016 and 2017 preseason medical examinations. After the 2016 season, the participants completed questionnaires related to throwing-related shoulder and elbow pain, defined as an inability to play for ≥1 week because of elbow or shoulder difficulties. For study participants with and without throwing-related shoulder or elbow pain during the 2016 season, we conducted univariate and multivariate logistic regression analysis to identify risk factors for throwing-related shoulder or elbow pain.

Results:

Overall, 21 players (12.8%) reported a shoulder pain episode, 56 players (34.1%) had an elbow pain episode, and 70 players (42.7%) reported having experienced shoulder and/or elbow pain during the 2016 season. In multivariate logistic regression analysis, (1) shoulder pain was associated with 2016 preseason height (odds ratio [OR], 1.06; 95% CI, 1.01-1.11; P = .01) and change in dominant-side elbow extension ROM from 2016 to 2017 (OR, 1.12; 95% CI, 1.02-1.24; P = .02); (2) elbow pain was associated with change in weight from 2016 to 2017 (OR, 1.21; 95% CI, 1.04-1.41; P = .014); and (3) throwing-related shoulder and/or elbow pain was associated with greater 2016 preseason height (OR, 1.04; 95% CI, 1.003-1.68; P = .03) and an increase in height from 2016 to 2017 (OR, 1.17; 95% CI, 1.01-1.35; P = .03).

Conclusion:

Our results indicated that adolescent baseball players who were taller in the preseason and those with an increase in height over the 1-year study period faced significant risks for developing throwing-related shoulder and/or elbow pain.

The PITCH study: pitcher injuries during the first 30 days of the coronavirus disease 2019 halted Major League Baseball season

Background

Major League Baseball (MLB) was among the first professional team sports leagues to resume play in the United States after public health measures related to the appearance of coronavirus disease 2019 caused interruptions to preseason training and major alterations to regular season play. There was a high level of concern that these athletes were ill-prepared for competition and would experience an increased risk of injury under the restricted play rules.

Methods

The data in our study were compiled using publicly accessible records of players placed on injured lists from 2015 to 2020. These records came from 4 open access websites: rotoworld.com, fangraphs.com, foxsports.com, and spotrac.com. All injuries were confirmed using the transaction database found on the official MLB website (mlb.com).

Results

A greater proportion of pitchers were injured during the first 30 days of the 2020 season compared to the first 30 days of any of the 5 prior seasons (29.74% vs. 11.72%, n=2190, P<.001). There was a demonstrated increase in injury risk in 2020 for the following anatomic locations: back and trunk, shoulder, upper arm and elbow, forearm and wrist, and hand and finger (P=.02; confidence interval [0.497-5.783]). When dividing the first month of play in 2020 into equal halves (15 days each), the number of relief pitcher injuries increased with time (60% vs. 78%, P=.04). Lastly, there was no proportional difference in placement on the short-term vs. long-term injured list.

Conclusion

A significantly large increase in soft tissue injuries in 2020 compared to the prior 5 seasons predominantly affected the trunk and the upper extremity of pitchers in the first 30 days of play. Alterations to preseason training and regular season play in the 2020 MLB season due to coronavirus disease 2019 may have been particularly disadvantageous to professional pitchers who are positioned at baseline, the most injury prone position.

Effect of core muscle strengthening on throwing velocity in cricket players in Pakistan: a 6-week randomized controlled trial

BACKGROUND

During fielding throwing ball with more velocity and accuracy towards the stump to reduce score and produce an out of the opponent team. Core is the power house of the body. Core training improves the strength of trunk muscles and allows the players to kick, throw, pull, and push with greater force.

AIM

This study was conducted to determine the effects of core muscle strengthening on throwing velocity in cricket players that whether core muscle strengthening would help the cricket players to improve their throwing velocity and core endurance.

METHODS

A 6 weeks randomized controlled trial in which Ninety-eight male cricket players participated and divided into strength training (interventional) and non-strength training (control group). Interventional group followed general core strengthening exercise protocol for six weeks for 3 days a week. Assessment of the players include core assessment test (back extension, supine forward flexion test, prone bridge test). Time and throwing velocity was noted by stop watch and radar gun in km/hr respectively at baseline and after 6 weeks of core training. Control group did not follow any exercise program but continued their usual cricket training.

RESULTS

Mean age of interventional group was 20.4±4.9 years and control group was 21.6±3.4 years. The mean BMI of interventional and control group was 22.4±2.7 kg/m2 and 21.8±2.1 kg/m2, respectively. Comparing both groups, in between group analysis stregnth training group results showed statistically highly significant increase p<0.001 in compoments 'throwing velocity, back extension, supine flesion , right plank lateral, left lateral planl and isometric prone plank' than non strengthing group. In within group analysis, strength group had improved as compared to the control group which showed no improvement.

CONCLUSIONS

There is significant increase in throwing velocity and core endurance with six weeks general core stregthening in male cricket players.

A Nation-Wide Survey of High School Baseball Coaches' Perceptions Indicates their Arm Care Programs Play a Role in Injury Prevention

BACKGROUND

Arm care programs consisting of upper extremity strengthening and stretching have been recommended for injury prevention for pitchers of all ages. There has been no investigation into high school baseball coaches' usage and perceptions of arm care programs to mitigate physical impairments associated with injuries in baseball players.

HYPOTHESIS/PURPOSE

The purpose of this study was to investigate the current usage of arm care programs by high school baseball coaches. The primary objective was to determine if coaches use group-based or individualized arm care programs. The secondary objective sought to determine if the use of arm care programs is influenced by coaches' age, education, and experience level. Finally, this study explored the potential barriers to arm care implementation and high school baseball coaches' current awareness and beliefs of injury prevention.

STUDY DESIGN

Descriptive cross-sectional survey.

METHODS

A 29-item online survey was emailed to 18,500 high school baseball coaches throughout the United States. Data were collected for three months, and the response rate was 3.7%.

RESULTS

A total of 87.3% (n=571/654) of responding coaches use arm care programs with their players. Of coaches performing arm care, only 18.5% of 571 individualize their arm care exercises based on specific player needs. However, older and more experienced coaches are more likely to individualize their programs. Among the 12.7% (n=83/654) of coaches who do not use arm care programs, the two most commonly cited reasons for not implementing arm care were lack of observed benefit (41%) and insufficient staff (31%). Although 42% of 654 coaches recognized reduced shoulder mobility as a major contributor to injury, risk factors such as throwing with a fatigued arm, previous injury history, and throwing > 8 months per year were not consistently identified as primary risk factors.

CONCLUSION

The results of this study suggest that the majority high school baseball coaches implement group-based arm care exercise programs to prevent injury. Lack of confidence in the effectiveness and staffing limitations were major barriers to implementation of arm care programming. However, the responding coaches exhibited inconsistent risk factor awareness and dated injury prevention beliefs. Therefore, better educational collaboration between rehabilitation professionals and high school coaches regarding injury risk factors and preventative strategies is warranted.

LEVEL OF EVIDENCE

Level 3.

Epidemiology and pain in elementary school-aged players: a survey of Japanese badminton players participating in the national tournament

Pain is common in athletes which should be well managed. To identify risk factors for shoulder pain, and the association between shoulder pain, lower back pain and knee pain among elementary school-aged badminton players, we conducted a cross-sectional study to collect data of the past year among 611 elementary school age (7-12 years old) badminton players belonging to the Japan Schoolchildren Badminton Federation using a questionnaire. Odds ratio (OR) and 95% confidence interval (CI) were estimated by multivariate logistic regression analysis. The overall incidence rate of shoulder injuries, lower back injuries and knee injuries was 0.38 injuries per 1000 h of badminton training. Players with training time per day > 2.5 h were 2.64 times (95% CI 1.03-6.78, p = 0.043) more likely to sustain shoulder pain than those with training time per day ≤ 2.5 h. A significant association was revealed between shoulder pain and knee pain as well as between lower back pain and knee pain as training hours per day > 2.5 h. Moreover, lower back pain was significantly associated with shoulder pain independent of training hours per day (≤ 2.5 h: p = 0.001; > 2.5 h: p < 0.001). These findings indicate that training time per day is risk factor, and shoulder pain, lower back pain and knee pain were associated with each other in elementary school-aged badminton players.

Limiting the Pitch Count in Youth Baseball Pitchers Decreases Elbow Pain

Background

Reducing the number of pitches thrown is regarded as the most effective way to prevent throwing injuries in youth baseball pitchers. However, few studies have compared the effectiveness of limiting the pitch count versus the limiting the number of innings pitched in terms of elbow injuries.

Hypothesis

We hypothesized that, compared with inning limits, pitch count limits would lead to greater decreases in elbow pain, range of motion deficits, positive moving valgus stress test results, and the risk of capitellar osteochondritis dissecans (OCD).

Study Design

Cohort study; Level of evidence, 3.

Methods

This study retrospectively reviewed baseball pitchers aged 8 to 12 years in 2017 and 2018. Inning and pitch count limits in games were set to a daily maximum of 7 innings in 2017 and 70 pitches in 2018. Elbow pain, range of motion, and moving valgus stress test results were evaluated. The presence of capitellar OCD was assessed on ultrasonographic and radiographic images.

Results

A total of 352 pitchers in 2017 and 367 pitchers in 2018 participated. The mean pitch count per game was lower in the pitch count limit (CL) group (52.5 ± 16.0) than in the inning limit (IL) group (98.2 ± 19.5) (P < .001). Compared with the IL group, the CL group had significantly lower rates of elbow pain (40.9% vs 31.9%, respectively; P = .01) and reduced flexion (19.0% vs 10.6%, respectively; P = .001). Multivariate analysis revealed a significant association between elbow pain and age in both the IL and the CL groups (P < .0001 and P = .02, respectively) and between OCD and elbow pain in the CL group (P = .04).

Conclusion

A pitch count limit of ≤70 pitches per day for baseball pitchers ≤12 years could be more protective against elbow pain and reduced flexion than a limit of ≤7 innings per day, but it may not be effective for reducing the risk of capitellar OCD.

Ankle dorsiflexion deficit in the back leg is a risk factor for shoulder and elbow injuries in young baseball players

The relationship between ankle joint function and throwing-related injuries has not been demonstrated. We hypothesized that limited ankle joint range of motion (ROM) was related to risk factors for shoulder and elbow injuries in young baseball players. This 12-month prospective cohort study evaluated the age, height, weight, playing position, shoulder, elbow, and ankle function of 228 enrolled baseball players. Shoulder and elbow injuries were tracked during the season. Univariate and multivariate analyses were performed to identify risk factors for shoulder and elbow injuries among participants divided into non-injured and injured groups. Univariate analysis showed that age, height, weight, ROM of elbow flexion in the dominant arm, muscle strength ratio of shoulder abduction, and the likelihood of being a pitcher or a catcher were significantly greater in the injured group than in the non-injured group. ROM of shoulder abduction-external/internal rotation, shoulder total arc on the dominant arm, ankle joint dorsiflexion, and plantar flexion on the back (non-lead) and front (lead) legs were significantly less in the injured group than in the non-injured group. In conclusion, ROM dorsiflexion deficits in the back leg, shoulder abduction-external rotation in the dominant arm, ROM increase in elbow flexion on the dominant side, older age, and being a pitcher were significant independent risk factors for injury.

Relationship Between Upper Limb Injuries and Hip Range of Motion in Elementary and Junior High School Baseball Players

Background:

Shoulder and elbow injuries are major problems in baseball players. Tightness of the upper extremities has been reported as a risk factor for shoulder and elbow injuries in elementary and junior high school baseball players. However, few studies have been conducted on the relationship between decreased hip range of motion (ROM) and shoulder and elbow injuries.

Purpose/Hypothesis:

This study aimed to prospectively examine the relationship between hip ROM and throwing-related shoulder and elbow injuries in elementary and junior high school baseball players. The hypothesis was that players with unrestricted ROM in the hip would have a reduced risk of upper extremity injuries.

Methods:

The study included 263 baseball players (mean ± SD age, 10.5 ± 1.3 years; range, 7-14 years). The following physical parameters were assessed: (1) hip flexion ROM measured in the supine position and (2) hip internal and external rotation in the prone position. After the season, players completed questionnaires regarding shoulder and/or elbow injuries. For comparison, the players were classified as injured (not able to play for ≥8 days because of shoulder and/or elbow problems) or noninjured.

Results:

During the season, 52 players had shoulder and/or elbow injuries. When the injured and noninjured groups were compared, hip flexion on the dominant side (121.5° ± 12.0° vs 126.7° ± 9.8°, respectively; P < .01), hip flexion on the nondominant side (119.6° ± 11.7° vs 126.0° ± 9.9°, respectively; P < .01), and internal rotation on the dominant side (52.5° ± 11.3° vs 56.8° ± 10.8°, respectively; P = .01) were significantly reduced in the injured group.

Conclusion:

We identified preseason decreases in flexion bilaterally and internal rotation on the dominant side as risk factors for shoulder and elbow injuries in elementary and junior high school baseball players. Further studies are required to prevent disabilities in elementary and junior high school baseball players through development of prevention and intervention programs.

High baseball loads induce shoulder and elbow injuries among high school baseball pitchers: a prospective study

Studies on the relationship between baseball loads (practice, training, and competition hours) and shoulder and elbow injuries among high school pitchers are limited. Therefore, this study included 92 male high school baseball pitchers and evaluated their preseason shoulder and elbow conditions. All participants completed a self-recorded questionnaire regarding baseball load, presence of shoulder pain or elbow pain, or both, and pitching limitations due to shoulder and/or elbow pain experienced daily to determine the occurrence of injuries and record the baseball load. The optimal load cutoff value was determined using a receiver operating characteristic curve analysis. Participants were categorized into high-load and low-load groups according to the aforementioned cutoff value. The Kaplan-Meier method was used to obtain time-to-event curves, and cox proportional hazards models were used to calculate the hazard ratios for injury rates. The cutoff value of the average baseball load was 324.4 min per day. A high load (> 5.5 h/day) led to a 2.6-times greater risk of injuries and 3.3-times earlier occurrence of injuries than a low load (< 5.5 h/day). Therefore, a high load is a risk factor for shoulder and elbow injuries in high school baseball pitchers.

A small number of daily pitches induces shoulder and elbow injuries among high school baseball pitchers: a prospective study

Baseball players frequently injure their shoulders and elbows. Preseason risk factors for such injuries have been relatively well studied, but in-season risk factors are less known, and the relationship between the number of pitches and the incidence of such injuries in baseball pitchers of any level is unclear. Identifying the risk factors related to the number of daily pitches is particularly important to prevent baseball-related arm injuries among young pitchers. Thus, we prospectively investigated the relationship between the number of daily full-power pitches in high school baseball pitchers and the incidence of shoulder and elbow injuries. We observed that a small number of daily full-power pitches, < 30 pitches per day, in high school baseball pitchers, significantly increased the risk of shoulder and elbow injuries: these players had a 2.3-times greater risk of injuries and a 45-day earlier occurrence of injuries than those pitching ≥ 30 pitches per day. Although unexpected, this was plausible as continuous daily pitching is required to maintain physical condition in growing and maturing high school pitchers. These findings may form the basis for establishing guidelines regarding the appropriate number of daily pitches required to prevent shoulder and elbow injuries in high school baseball pitchers.

Risk Factors of Overuse Shoulder Injuries in Overhead Athletes: A Systematic Review

CONTEXT

Shoulder injuries are highly prevalent in sports involving the upper extremity. Some risk factors have been identified in the literature, but consensus is still lacking.

OBJECTIVES

To identify risk factors of overuse shoulder injury in overhead athletes, as described in the literature.

DATA SOURCES

A systematic review of the literature from the years 1970 to 2018 was performed using 2 electronic databases: PubMed and Scopus.

STUDY SELECTION

Prospective studies, written in English, that described at least 1 risk factor associated with overuse shoulder injuries in overhead sports (volleyball, handball, basketball, swimming, water polo, badminton, baseball, and tennis) were considered for analysis.

STUDY DESIGN

Systematic review.

LEVEL OF EVIDENCE

Level 3.

DATA EXTRACTION

Data were extracted from 25 studies. Study methodology quality was evaluated using the Modified Coleman Methodology Score.

RESULTS

Intrinsic factors, previous injury, range of motion (lack or excess), and rotator cuff weakness (isometric and isokinetic) highly increase the risk of future injuries. Additionally, years of athletic practice, body mass index, sex, age, and level of play seem to have modest influence. As for the effect of scapular dysfunction on shoulder injuries, it is still controversial, though these are typically linked. Extrinsic factors, field position, condition of practice (match/training), time of season, and training load also have influence on the occurrence of shoulder injuries.

CONCLUSION

Range of motion, rotator cuff muscle weakness, and training load are important modifiable factors associated with shoulder injuries. Scapular dysfunction may also have influence. The preventive approach for shoulder injury should focus on these factors.

Sport Specialization and Overuse Injuries in Adolescent Throwing Athletes: A Narrative Review

A significant number of adolescent athletes throughout the world participate in various throwing-dominant sports, including but not limited to baseball, cricket, handball, softball, track and field throwing events, and water polo. Due to the unique stresses placed on the throwing arm and entire body in these sports, a robust volume of literature has highlighted concerns about sport specialization in these athletes and an associated increased risk of injury, particularly to the dominant shoulder and elbow, with sport specialization. This review will highlight the evidence-based literature for this athletic niche, focusing on risk factors for injury, national and international organizations' recommendations for limiting overuse injuries, principles of conditioning and rehabilitative programs, and potential future areas of research to curb the growing incidence of throwing-related injuries among adolescent throwing athletes.

Osteochondritis Dissecans of the Capitellum :Review of the Literature

Osteochondritis dissecans (OCD) of the capitellum is a leading cause of elbow disability in adolescent baseball players. Previous studies have not found an association of player position with capitellar OCD. Elbow pain and a longer playing history might be related to progression of capitellar OCD but do not in themselves increase the risk of development of the condition. The cause of capitellar OCD is likely to include a combination of repetitive microtrauma and internal factors, such as ischemia and genetic predisposition. A combination of radiography, computed tomography, magnetic resonance imaging, and ultrasonography have aided our understanding of the pathology of capitellar OCD. Screening using ultrasonography enables early detection and provides an opportunity for successful conservative treatment. Treatment has conventionally included both operative and nonoperative measures based on the stage and size of the lesion, skeletal maturity, subjective symptoms, and structural integrity of the cartilage. Early-stage lesions respond better to nonoperative treatment than those in more advanced stages. Operative indications include persistent symptoms despite nonoperative treatment, symptomatic loose bodies, and displacement or detachment of fragments. J. Med. Invest. 67 : 217-221, August, 2020.

Risk Factors for Baseball-Related Arm Injuries: A Systematic Review

Background:

Contributing factors for arm injuries among baseball players have been described. However, no review has systematically identified risk factors with findings from prospective cohort studies.

Purpose:

To systematically review prospective cohort studies that investigated risk factors for arm injury among baseball players.

Study Design:

Systematic review; Level of evidence, 3.

Methods:

Electronic databases were searched for relevant English-language studies. Titles, abstracts, and full-text articles were screened by 2 blinded reviewers to identify only prospective cohort studies and randomized controlled trials. Two independent investigators screened each article for appropriate criteria.

Results:

Fourteen prospective articles were selected for this review. Youth, high school, and professional baseball players (N = 2426) were pooled, and 43 risk factors were assessed in relation to general arm, shoulder, and elbow injuries. All studies evaluated players for at least 1 season. Deficits in preseason shoulder range of motion and strength were significant risk factors for general arm or shoulder injury among high school and professional players. Elbow and shoulder varus torque at peak external shoulder rotation during pitching, high pitch velocity, and shoulder rotational and flexion deficits were risk factors for elbow injuries among professional pitchers. Pitching >100 innings in 1 year, being aged 9 to 11 years, being a pitcher or catcher, training >16 hours per week, and having a history of elbow pain were significant risk factors for elbow injury among youth players.

Conclusion:

History of elbow pain and age had a high risk of associated elbow injury among youth players. Training or pitching load also increased elbow injury risk for youth athletes. Loss of shoulder range of motion appears to increase risk for elbow injury among professional athletes. Single time-point data collections per season, studies with the same sample population, and studies with self-reported injury and risk factor data may limit the interpretation of these findings. Health care professionals should use caution when assessing injury risk during evaluation and making decisions about the training workload and playing time of baseball players.

Risk factors for, and prevention of, shoulder injuries in overhead sports: a systematic review with best-evidence synthesis

Objective

To assess the evidence for risk factors and prevention measures for shoulder injuries in overhead sports.

Design

Systematic review with best-evidence synthesis.

Data sources

Medline (Ovid), PubMed (complementary search), Embase (Elsevier), Cochrane (Wiley), SPORTDiscus (Ebsco) and Web of Science Core Collection (Thomson Reuters), from 1 January 1990 to 15 May 2017.

Eligibility criteria for selecting studies

Randomised controlled trials, cohort studies and case-control studies on risk factors or prevention measures for shoulder injuries in overhead sports. The eligible studies were quality assessed using the Scottish Intercollegiate Guidelines Network criteria.

Results

Of 4778 studies identified, 38 were eligible for quality review and 17 met the quality criteria to be included in the evidence synthesis. One additional quality study presented a shoulder injury prevention programme. Most studies focused on baseball, lacrosse or volleyball (n=13). The risk factors examined included participation level (competition vs training) (n=10), sex (n=4), biomechanics (n=2) and external workload (n=2). The evidence for all risk factors was limited or conflicting. The effect of the prevention programme within the subgroup of uninjured players at baseline was modest and possibly lacked statistical power.

Conclusions

All investigated potential risk factors for shoulder injury in overhead sports had limited evidence, and most were non-modifiable (eg, sex). There is also limited evidence for the effect of shoulder injury prevention measures in overhead sports.

PROSPERO trial registration number

CRD42015026850.