Haff G Gregory, Ruben Ryan P, Lider Joshua, Twine Corey, Cormie Prue
1Center for Exercise and Sport Science Research, Edith Cowan University, Joondalup, Western Australia, Australia; 2Department of Exercise Physiology, West Virginia University School of Medicine, Morgantown, West Virginia; 3Athletics Department, West Virginia University, Morgantown, West Virginia; and 4Edith Cowan University Health and Wellness Institute, Edith Cowan University, Joondalup, Western Australia, Australia.
J Strength Cond Res. 2015 Feb;29(2):386-95. doi: 10.1519/JSC.0000000000000705.
Twelve female division I collegiate volleyball players were recruited to examine the reliability of several methods for calculating the rate of force development (RFD) during the isometric midthigh clean pull. All subjects were familiarized with the isometric midthigh clean pull and participated in regular strength training. Two isometric midthigh clean pulls were performed with 2 minutes rest between each trail. All measures were performed in a custom isometric testing device that included a step-wise adjustable bar and a force plate for measuring ground reaction forces. The RFD during predetermined time zone bands (0-30, 0-50, 0-90, 0-100, 0-150, 0-200, and 0-250 milliseconds) was then calculated by dividing the force at the end of the band by the band's time interval. The peak RFD was then calculated with the use of 2, 5, 10, 20, 30, and 50 milliseconds sampling windows. The average RFD (avgRFD) was calculated by dividing the peak force (PF) by the time to achieve PF. All data were analyzed with the use of intraclass correlation alpha (ICCα) and the coefficient of variation (CV) and 90% confidence intervals. All predetermined RFD time bands were deemed reliable based on an ICCα >0.95 and a CV <4%. Conversely, the avgRFD failed to meet the reliability standards set for this study. Overall, the method used to assess the RFD during an isometric midthigh clean pull impacts the reliability of the measure and predetermined RFD time bands should be used to quantify the RFD.
招募了12名美国大学体育协会（NCAA）一级联赛的女子排球运动员，以检验几种计算等长中大腿借力上拉过程中力发展速率（RFD）方法的可靠性。所有受试者均熟悉等长中大腿借力上拉，并参加常规力量训练。进行了两次等长中大腿借力上拉，每次试验之间休息2分钟。所有测量均在定制的等长测试设备中进行，该设备包括一个可逐步调节的横杆和一个用于测量地面反作用力的测力板。然后，通过将该时间段末尾的力除以该时间段的时间间隔，计算预定时间段（0 - 30、0 - 50、0 - 90、0 - 100、0 - 150、0 - 200和0 - 250毫秒）内的RFD。随后，使用2、5、10、20、30和50毫秒的采样窗口计算峰值RFD。平均RFD（avgRFD）通过将峰值力（PF）除以达到PF的时间来计算。所有数据均使用组内相关系数α（ICCα）、变异系数（CV）和90%置信区间进行分析。基于ICCα>0.95且CV<4%，所有预定的RFD时间段被认为是可靠的。相反，avgRFD未达到本研究设定的可靠性标准。总体而言，用于评估等长中大腿借力上拉过程中RFD的方法会影响测量的可靠性，应使用预定的RFD时间段来量化RFD。
