Department of Health, Kinesiology, Recreation, and Dance, University of Arkansas, Fayetteville, Arkansas, USA.
J Strength Cond Res. 2010 Sep;24(9):2400-7. doi: 10.1519/JSC.0b013e3181dc43af.
This study examined the joint motions and movement patterns of the kinetic chain in the ballistic skill of performing the windmill pitch. Seventeen healthy girls who were currently playing competitive fast-pitch softball volunteered for the study. Subjects were instructed to perform 5 successful fastball windmill style deliveries. We selected 1 pitch for analysis based on the velocity, accuracy, and subjects' input. Kwon3D motion analysis package (Visol., Inc., Seoul, Korea), with 6 digital camcorders placed at 60 degrees apart was used for analysis. Raw data were interpolated using a frequency of 60 Hz and then smoothed using Butterworth low-pass second-order filter with a fixed cut-off frequency of 6 Hz. The subjects were divided into groups based on skill level: novice, intermediate, and advanced. Sequential progression of kinematic variables that resulted in increased throwing velocity and the contribution each segment (upper arm, forearm, and hand) possessed toward ball velocity with descriptive statistics and path analysis were assessed. There was evidence of sequentiality among the arm segments in the intermediate and advanced groups. The patterns of the shared positive contributions made by each of the limb segments were similar among the 3 groups of participants. The novice group tended to rely on more of the upper arm and forearm than the other 2 groups. From this study, it is evident that all emphasis should not be placed on the shoulder, but training and conditioning methods should focus on the entire kinetic chain including the torso and the full arm segment, not just the shoulder in an attempt to gain the greatest velocity while performing the 360 degrees arc of the windmill softball pitch.
本研究考察了在投球的风车式投球动作中，动力链的联合运动和运动模式。17 名正在参加竞技快投垒球的健康女孩自愿参加了这项研究。受试者被要求完成 5 次成功的快球风车式投球。我们根据速度、准确性和受试者的输入选择了 1 个投球进行分析。使用了 6 个放置在 60 度角的数字摄像机的 Kwon3D 运动分析包（Visol.， Inc.，首尔，韩国）进行分析。原始数据使用 60 Hz 的频率进行内插，然后使用巴特沃斯低通二阶滤波器进行平滑处理，截止频率固定为 6 Hz。根据技能水平将受试者分为新手、中级和高级组。使用描述性统计和路径分析评估了导致投掷速度增加的运动学变量的顺序进展以及每个部分（上臂、前臂和手）对球速的贡献。在中级和高级组中，手臂各节段之间存在顺序性的证据。3 组参与者的每个肢体节段的共同正贡献模式相似。新手组倾向于比其他 2 组更多地依赖上臂和前臂。从这项研究中可以明显看出，不应该只强调肩部，而应该通过训练和调理方法来关注整个动力链，包括躯干和整个手臂部分，而不仅仅是肩部，从而在执行 360 度的风车式垒球投球时获得最大速度。
