The Salford Institute of Human Movement and Rehabilitation, University of Salford, Salford, UK.
Department of Elite Training Science and Technology Division, Hong Kong Sports Institute, Hong Kong, China.
J Sports Sci. 2022 Aug;40(15):1658-1667. doi: 10.1080/02640414.2022.2091351. Epub 2022 Aug 11.
The effect of load on time-series data has yet to be investigated during weightlifting derivatives. This study compared the effect of load on the force-time and velocity-time curves during the countermovement shrug (CMS). Twenty-nine males performed the CMS at relative loads of 40%, 60%, 80%, 100%, 120%, and 140% one repetition maximum (1RM) power clean (PC). A force plate measured the vertical ground reaction force (VGRF), which was used to calculate the barbell-lifter system velocity. Time-series data were normalized to 100% of the movement duration and assessed via statistical parametric mapping (SPM). SPM analysis showed greater negative velocity at heavier loads early in the unweighting phase (12-38% of the movement), and greater positive velocity at lower loads during the last 16% of the movement. Relative loads of 40% 1RM PC maximised propulsion velocity, whilst 140% 1RM maximized force. At higher loads, the braking and propulsive phases commence at an earlier percentage of the time-normalized movement, and the total absolute durations increase with load. It may be more appropriate to prescribe the CMS during a maximal strength mesocycle given the ability to use supramaximal loads. Future research should assess training at different loads on the effects of performance.
在举重衍生动作中，还需要研究负荷对时间序列数据的影响。本研究比较了在反弓挺举（CMS）中负荷对力-时间和速度-时间曲线的影响。29 名男性以相对负荷 40%、60%、80%、100%、120%和 140%的 1 次重复最大力量（1RM）深蹲翻的方式进行了 CMS。力板测量垂直地面反作用力（VGRF），用于计算杠铃-举重者系统速度。时间序列数据被归一化为运动持续时间的 100%，并通过统计参数映射（SPM）进行评估。SPM 分析显示，在减重阶段早期（运动的 12%-38%），负荷越重，负向速度越大，而在运动的最后 16%，负荷越低，正向速度越大。40% 1RM PC 的相对负荷使推进速度最大化，而 140% 1RM 则使力量最大化。在更高的负荷下，制动和推进阶段在时间归一化运动的较早百分比开始，并且总绝对持续时间随负荷增加而增加。鉴于能够使用超最大负荷，在最大力量中周期期间规定 CMS 可能更为合适。未来的研究应该评估不同负荷对运动表现的影响。
