Differences in humeral retroversion in dominant and nondominant sides of young baseball players

Daisuke Kurokawa, Nobuyuki Yamamoto, Hiroaki Ishikawa, Hideaki Nagamoto, Hiroyuki Takahashi, Takayuki Muraki, Minoru Tanaka, Katsumi Sato, Eiji Itoi

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


Background The relationship between the disabled throwing shoulder and humeral retroversion has recently attracted a great deal of attention. However, none of the previous studies clarified when the side-to-side difference of humeral retroversion in young baseball players would start. This study aimed to clarify when the difference of humeral retroversion in the dominant and nondominant sides appeared in baseball players. Methods The bicipital-forearm angle in bilateral shoulders of 172 elementary school baseball players was measured by ultrasound. The bicipital-forearm angle was defined as an angle between the perpendicular line to the bicipital groove and the ulnar long axis with the elbow flexed at 90°. The correlation between the bicipital-forearm angle and the grade and the difference of the bicipital-forearm angle between the dominant and nondominant sides were analyzed. Results In the nondominant shoulders, the bicipital-forearm angle increased with the grade in school (r = 0.32, P < .0001), but this was not observed in the dominant shoulders. In the fourth to sixth graders, the bicipital-forearm angles were significantly smaller in the dominant shoulders than in the nondominant shoulders. Conclusion Our findings indicated that humeral retroversion decreased with age in the nonthrowing side but not in the throwing side and that the side-to-side difference of humeral retroversion in the baseball players became obvious from the fourth grade. We assume that the repetitive throwing motion restricts the physiologic humeral derotation process and the difference became apparent from the fourth grade when the growth spurt begins in boys.

Original languageEnglish
Pages (from-to)1083-1087
Number of pages5
JournalJournal of Shoulder and Elbow Surgery
Issue number6
Publication statusPublished - 2017 Jun 1


  • Humeral retroversion
  • Little League shoulder
  • baseball player
  • growth period
  • throwing athlete
  • ultrasonography

ASJC Scopus subject areas

  • Surgery
  • Orthopedics and Sports Medicine


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