Department of Orthopaedic Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
Department of Orthopaedic Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
J Shoulder Elbow Surg. 2019 May;28(5):847-853. doi: 10.1016/j.jse.2018.10.017. Epub 2019 Jan 24.
Repetitive pitching in childhood was thought to restrict the physiological derotation process of the humeral head. Some studies reported that the side-to-side differences of humeral retroversion in baseball players occurred between the age of 9 and 11 years. The present study investigated the relationship between bilateral humeral retroversion angle and starting baseball age in skeletally mature baseball players.
One hundred and seventeen male baseball players, who belonged to a college or amateur team, were investigated. Bilateral humeral retroversion was assessed using an ultrasound-assisted technique as described by previous studies. All players were divided into four groups: players who had started playing baseball before the age of 6 years, between 7 and 8 years, between 9 and 10 years and after 11 years. Bilateral humeral retroversion angle was compared among the four starting age groups.
All players started playing baseball between 5 and 12 years. Comparing the throwing arm, humeral retroversion in starting age group 11-12 (72°) was significantly smaller than the other 3 groups (81°, 82°, and 80° for groups 5-6, 7-8, and 9-10, respectively). Comparing the non-throwing arm revealed no significant differences among the 4 starting age groups (71°, 72°, 70°, and 66° for groups 5-6, 7-8, 9-10, and 11-12, respectively).
Skeletally mature baseball players who started playing baseball after 11 years had significantly smaller humeral retroversion in the throwing arm than those who started baseball before 11 years.
人们曾认为儿童时期的重复性投球会限制肱骨头的生理回旋过程。一些研究报告称，棒球运动员的肱骨后旋在 9 至 11 岁之间存在侧向差异。本研究旨在探讨骨骼成熟的棒球运动员双侧肱骨后旋角度与开始棒球年龄之间的关系。
本研究调查了 117 名属于大学或业余棒球队的男性棒球运动员。采用先前研究描述的超声辅助技术评估双侧肱骨后旋。所有运动员均分为 4 组：6 岁以前开始打棒球的运动员、7 至 8 岁、9 至 10 岁、11 岁以后开始打棒球的运动员。比较了 4 个起始年龄组之间的双侧肱骨后旋角度。
所有运动员的起始年龄均在 5 至 12 岁之间。比较投掷臂，起始年龄组 11-12 岁（72°）的肱骨后旋明显小于其他 3 组（5-6 岁组为 81°，7-8 岁组为 82°，9-10 岁组为 80°）。比较非投掷臂，4 个起始年龄组之间无显著差异（5-6 岁组为 71°，7-8 岁组为 72°，9-10 岁组为 70°，11-12 岁组为 66°）。
骨骼成熟的棒球运动员，与 11 岁以前开始打棒球的运动员相比，11 岁以后开始打棒球的运动员投掷臂的肱骨后旋明显更小。
