Four-year trend in shoulder and elbow injuries in competitive-level high school baseball pitchers: a repeated cross-sectional survey

Incidence and Characteristics of Elbow Injury in Japanese Youth Baseball Players: Comparison Between 2011 and 2021

Background

Little League elbow, including humeral epicondylitis and osteochondritis dissecans, is a severe throwing injury in school-aged pitchers. Recent rule revisions have been implemented, and thus, prevention awareness may have increased.

Purpose

To compare the incidence of elbow injury in 2011 from a previous study with that in 2021 and examine changes in the incidence and characteristics of players with elbow injuries.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

A survey based on the 2011 survey was conducted from September 1 to December 31, 2021, among 4060 third- to sixth-grade Little League players belonging to 203 teams in Kyoto, Japan. This survey included a 23-item checklist on physical condition and injury. The participants were classified into 2 groups according to the presence or absence of an elbow injury in the dominant arm during the season. The Wilcoxon rank-sum test was conducted to compare differences in basic information between the 2 groups. We also compared the differences in the 23 checklist items between the 2 groups using the chi-square or Fisher exact probability test.

Results

Overall, 98 teams (1335 players; age range, 8-12 years) returned the questionnaires (collection rate, 32.9%). The final analysis population (excluding incomplete questionnaires) was 678 (mean age, 10.6 ± 1.1 years). Elbow injuries accounted for 30.7% of all injury sites in the players. Overall, 61 players (9.0%) reported elbow injuries in 2021 compared with 19.1% of the players in the 2011 survey (P < .01) A significantly higher percentage of players with elbow injuries had elbow pain in extension (item 2 on the survey checklist, P < .001) and flexion (item 4, P < .0024), were regular players (item 5, P = .0288), played baseball under fatigue (item 8, P = .0028), and had lower and upper limb inflexibility (item 17, P = .0379; item 18, P = .0146; and item 22, P = .0085).

Conclusion

Study findings indicated that the incidence of elbow injuries has decreased significantly over the past 10 years, although the elbow joint still accounted for almost one-third of all injuries in Japanese youth baseball players.

Shoulder stretching versus shoulder muscle strength training for the prevention of baseball-related arm injuries: a randomized, active-controlled, open-label, non-inferiority study

Glenohumeral internal rotation deficit (GIRD) and weakness in prone external rotation are risk factors for shoulder and elbow injuries in high school baseball pitchers. While a shoulder-stretching prevention program to improve GIRD decreases the injury rate, the effects of external rotation strength remain unclear. This non-inferiority (NI) study investigates the hypothesis that external rotation strength training is not inferior to sleeper stretching for shoulder and elbow injury prevention in high school baseball pitchers. Participants were randomly allocated to the stretching (n = 62; active control group) and muscle-training (n = 51) groups. Specific exercises were performed each night. Elbow and shoulder injuries were monitored for 150 days. Kaplan-Meier survival curves were generated, and the hazard ratios (HRs) for injury occurrence were calculated using multivariate Cox regression. The log-rank test was used to compare the injury-free time. A one-sided NI test using a fixed NI margin was performed (significance level, P = 0.025). The injury rates were 22.6% (n = 14) in the stretching group and 9.8% (n = 5) in the muscle-training group. The muscle-training group had a lower injury rate (P < 0.001) and a lower risk of injury than the stretching group (HR = 0.489). Therefore, external rotation muscle strength training is not inferior to stretching for preventing baseball-related arm injuries.

Lower extremity injuries in the baseball athlete

Baseball is unique in its multiple facets: pitching, hitting, base rounding, and fielding are distinct activities that require different athletic skills to perform at a high level. Likewise, these different aspects of the game can contribute to a multitude of varying injuries. While high-velocity overhead throwing, along with batting, can produce a plethora of upper extremity injuries that often garner attention, injuries to the lower extremity can severely impact a player’s performance and ability to compete. The rigors of the short, explosive sprinting required for base running, as well as the dynamic movement required for fielding, create ample opportunity for lower limb injury, and even subtle pathology can affect a pitcher’s ability to perform or increase their long-term risk of injury. Chronic injury from conditions such as femoroacetabular impingement and hip labral tears can also occur. The purpose of the present review is to summarize the relevant epidemiology, pathophysiology, and treatment of lower extremity injuries in baseball athletes, with reference to current research into the prevention and management of such injuries.