Southard Dan
Department of Kinesiology, Texas Christian University, Fort Worth 76129, USA.
Res Q Exerc Sport. 2006 Sep;77(3):316-25. doi: 10.1080/02701367.2006.10599366.
The purpose of this study was to determine the effects of instruction and scaling up a control parameter (velocity of throw) on changes in throwing pattern. Sixty adult female throwers (ages 20-26 years) were randomly placed into one offour practice conditions: (a) scale up on velocity with no instruction, (b) maintain constant velocity with no instruction, (c) maintain constant velocity with instruction, and (d) scale up on velocity with instruction. Participants in each condition were required to practice throwing with the nondominant arm twice per week for 5 weeks (10 sessions). Practice consisted of 20 throws per session. Participants in conditions including instruction were encouraged to rotate the trunk in an attempt to take advantage of the order parameter. Analysis indicated that each condition improved relative to use of the open kinetic chain. However, participants who increased velocity were more likely to attain maximum use of the order parameter with less practice. Additionally, throwers who increased velocity without instruction attained an optimal pattern of complete distal lag one session earlier than those who increased velocity with instruction. Data indicated that for those conditions without instruction, hand to forearm lag (H-F lag) occurred before humeral lag. It was concluded that emphasizing proximal movement (trunk rotation) without increasing velocity does not result in a final pattern that uses H-F lag.
本研究的目的是确定指导以及扩大一个控制参数（投掷速度）对投掷模式变化的影响。60名成年女性投掷者（年龄20 - 26岁）被随机分配到以下四种练习条件之一：(a) 无指导下扩大速度，(b) 无指导下保持恒定速度，(c) 有指导下保持恒定速度，以及(d) 有指导下扩大速度。每个条件下的参与者被要求每周用非优势手臂练习投掷两次，共5周（10节训练课）。每次训练课包含20次投掷。包含指导的条件下的参与者被鼓励转动躯干，以尝试利用序参量。分析表明，相对于开链运动的使用，每个条件都有改善。然而，提高速度的参与者更有可能在较少的练习次数下达到序参量的最大利用。此外，无指导下提高速度的投掷者比有指导下提高速度的投掷者提前一节课达到完全远端滞后的最佳模式。数据表明，对于那些无指导的条件，手到前臂的滞后（H - F滞后）发生在肱骨滞后之前。得出的结论是，不增加速度而强调近端运动（躯干转动）不会产生使用H - F滞后的最终模式。
