Characteristics of jump distance in asymptomatic elementary school baseball players with abnormal humeral medial epicondyles

Abstract

Our study aimed to investigate characteristics of jump distance and body size of 85 asymptomatic elementary school baseball players with abnormal humeral medial epicondyles. The following parameters were recorded: age, body size, bilateral forward jump distance, bilateral single forward, and lateral jump. Elbow injuries were classified based on physical examination findings of throwing pain and tenderness at the medial elbow joint and ultrasonographic findings. The distance jumped values were normalized by height. Participants with humeral medial epicondylar fragmentation, no tenderness, and subjective pain were classified as abnormal. Healthy group comprised those with no elbow pain or ultrasonographic findings. The two groups were compared using unpaired t-test. Abnormal and healthy groups comprised 15 and 62 participants, respectively. Bilateral single lateral jump distance of the abnormal group was significantly smaller than that of the healthy group. Age and body size of the injury group were significantly larger than those of the healthy group. Our study showed that the abnormal group had decreased bilateral single lateral jump and increased age and body sizes compared to those of the healthy group.