PURPOSE

Serious arm injuries in youth baseball players have been increasing. Though a breakage in the kinetic chain could affect arm injuries, an association between arm injuries and insufficient support of the trunk and lower extremities is not well understood. The purpose of this study was to investigate the association of low back and knee pain with elbow and/or shoulder complaints among youth baseball players.

METHODS

A self-administered questionnaire and document informed consent were mailed to youth athletes belonging to the Miyagi Amateur Sports Association. Multiple logistic regression analysis was used to examine the association of low back and knee pain with elbow and/or shoulder pain at the time of the questionnaire. Variables considered in the models were as follows: sex, age, BMI, years of athletic experience, position, team level, the amount of practice, participating day in team practice and game per week, frequency of participation in games, and practice intensity.

RESULTS

The final study population was comprised 1582 youth baseball players (aged 6-15 years old, male 95.6 %) who had responded to the questionnaire. A total of 24.8 % (n = 381) had elbow and/or shoulder pain, whereas 8.5 % (n = 130) had low back pain and 13.1 % (n = 201) had knee pain. The prevalence of elbow and/or shoulder pain with concomitant low back and knee pain was 61.2 % (n = 82) and 51.9 % (n = 108) (p < 0.001), respectively. The presence of low back and knee pain was significantly associated with the prevalence of elbow and/or shoulder pain among youth baseball players [adjusted odds ratio (ORs): 4.31, 95 % confidence interval (95 % CI): 2.86-6.51, p < 0.001, and ORs: 2.92, 95 % CI: 2.09-4.09, p < 0.001, respectively]. For other variables, older age (10- and 11-year old: ORs: 1.73, 95 % CI 1.10-2.73, p = 0.018; 12-15 year old: ORs: 1.62, 95 % CI: 1.18-2.58, p = 0.006), pitcher (ORs: 1.46, 95 % CI: 1.10-1.94, p = 0.009), catcher (ORs: 1.69, 95 % CI: 1.24-2.31, p = 0.001,), and practice intensity (ORs: 1.58, 95 % CI: 1.22-2.06, p = 0.001) were significantly associated with elbow and/or shoulder pain.

CONCLUSION

Both low back and knee pain were significantly associated with elbow and/or shoulder pain in youth baseball players. Clinicians should check the complaints of the trunk and lower extremities as well as those of the elbow and shoulder for preventing severe injuries in youth baseball players. Level of Evidence III.