Mercy St Vincent Medical Center, Toledo, Ohio, USA.
University of South Florida, Tampa, Florida, USA.
Orthop J Sports Med. 2015 Jan 22;3(1):2325967114566796. doi: 10.1177/2325967114566796. eCollection 2015 Jan.
Previous studies investigating the windmill softball pitch have focused primarily on shoulder musculature and function, collecting limited data on elbow and forearm musculature. Little information is available in the literature regarding the forearm. This study documents forearm muscle electromyographic (EMG) activity that has not been previously published.
Elbow and upper extremity overuse injuries are on the rise in fast-pitch softball pitchers. This study attempts to describe forearm muscle activity in softball pitchers during the windmill softball pitch. Overuse injuries can be prevented if a better understanding of mechanics is defined.
Descriptive laboratory study.
Surface EMG and high-speed videography was used to study forearm muscle activation patterns during the windmill softball pitch on 10 female collegiate-level pitchers. Maximum voluntary isometric contraction of each muscle was used as a normalizing value. Each subject was tested during a single laboratory session per pitcher. Data included peak muscle activation, average muscle activation, and time to peak activation for 6 pitch types: fastball, changeup, riseball, curveball, screwball, and dropball.
During the first 4 phases, muscle activity (seen as signal strength on the EMG recordings) was limited and static in nature. The greatest activation occurred in phases 5 and 6, with increased signal strength, evidence of stretch-shortening cycle, and different muscle characteristics with each pitch style. These 2 phases of the windmill pitch are where the arm is placed in the 6 o'clock position and then at release of the ball. The flexor carpi ulnaris signal strength was significantly greater than the other forearm flexors. Timing of phases 1 through 5 was successively shorter for each pitch. There was a secondary pattern of activation in the flexor carpi ulnaris in phase 4 for all pitches except the fastball and riseball.
During the 6 pitches, the greatest muscular activity was in phases 5 and 6. Flexor carpi ulnaris activity was greatest among the muscles tested. The riseball had the highest peak activity, but the curveball and dropball had the highest average signal strength. This muscle activity correlates with increasing distraction in the elbow, suggesting that flexor muscles act to counterdistract the elbow as they do for the baseball pitch.
Windmill pitchers are unique among overhead athletes as they throw, on average, more pitches per overhead athlete. Understanding the mechanics and physiology of the elbow in windmill pitchers is crucial to prevention and treatment of these increasingly common elbow injuries. This study establishes baseline data that will be useful to further prevent windmill pitch elbow injury.
之前研究旋转式投球的重点主要集中在肩部肌肉和功能上，对肘部和前臂肌肉的收集数据有限。文献中关于前臂的信息很少。本研究记录了以前未发表的前臂肌肉肌电图（EMG）活动。
在快投垒球投手中，肘部和上肢过度使用损伤的发生率正在上升。本研究试图描述旋转式垒球投手中的前臂肌肉在旋转式垒球投球中的活动。如果更好地理解力学，就可以预防过度使用损伤。
描述性实验室研究。
表面肌电图和高速录像用于研究 10 名女性大学水平投手在旋转式垒球投球中的前臂肌肉激活模式。每个肌肉的最大随意等长收缩被用作正常化值。每位受试者在每个投手的单个实验室会议中进行测试。数据包括 6 种投球类型的峰值肌肉激活、平均肌肉激活和达到峰值激活的时间：快球、变速球、上升球、曲线球、螺旋球和下降球。
在前 4 个阶段，肌肉活动（在肌电图记录上表现为信号强度）是有限的，性质是静态的。最大的激活发生在第 5 阶段和第 6 阶段，信号强度增加，证据表明伸展缩短周期，并且每种投球风格都有不同的肌肉特征。旋转式投球的这两个阶段是手臂放在 6 点钟位置，然后在球释放时。尺侧腕屈肌的信号强度明显大于其他前臂屈肌。各投球阶段 1 到 5 的时间相继缩短。除快球和上升球外，所有投球在第 4 阶段都有尺侧腕屈肌的二次激活模式。
在 6 个投球中，最大的肌肉活动发生在第 5 阶段和第 6 阶段。在测试的肌肉中，尺侧腕屈肌的活动最大。上升球的峰值活动最高，但曲线球和下降球的平均信号强度最高。这种肌肉活动与肘部的分散程度增加有关，这表明屈肌在棒球投球中起到抵消肘部分散的作用。
旋转式投手与其他头顶运动员不同，因为他们平均每投一个头顶运动员的球更多。了解旋转式投手中肘部的力学和生理学对于预防和治疗这些日益常见的肘部损伤至关重要。本研究建立了基线数据，这将有助于进一步预防旋转式投球肘部损伤。
