Moore Christopher A, Weiss Lawrence W, Schilling Brian K, Fry Andrew C, Li Yuhua
Exercise Neuromechanics Laboratory, University of Memphis, Memphis, Tennessee 38152, USA.
J Strength Cond Res. 2007 May;21(2):372-7. doi: 10.1519/R-18605.1.
The purpose of this study was to determine the acute effects of a spectrum of eccentric loads on force, velocity, and power during the concentric portion of maximal-effort jump squats utilizing a repeated measures design. Thirteen resistance-trained men (age = 22.8 +/- 2.9 years, weight = 87.1 +/- 11.8 kg, 163.5 +/- 28.6 kg squat 1 repetition maximum [1RM]; mean +/- SD), who routinely incorporated back squats into their training, participated as subjects in this investigation. Jump squat performance was assessed using 4 experimental conditions. The first of these conditions consisted of an isoinertial load equal to 30% of back squat 1RM. The remaining conditions consisted of jump squats with a concentric load of 30% 1RM, subsequent to the application of experimental augmented eccentric loading (AEL) conditions of 20, 50, and 80% of back squat 1RM, respectively. All subjects performed 2 sets of 1RM of maximum-effort jump squats with all experimental conditions in a counter-balanced sequence. Forty-eight hours after completing the first testing session, subjects repeated the experimental testing protocol to establish stability reliability. Peak performance values for the reliable variables of force, velocity, and power, as well as force and power values obtained at 20-ms intervals during the initial 400 ms of the concentric jump squat range of motion, showed no statistical difference (p > 0.05) across the experimental AEL loads. These results suggest that load-spectrum AEL prior to a 30% 1RM jump squat fails to acutely enhance force, velocity, and power.
本研究的目的是利用重复测量设计，确定一系列离心负荷对最大努力跳蹲向心阶段的力量、速度和功率的急性影响。13名进行抗阻训练的男性（年龄=22.8±2.9岁，体重=87.1±11.8 kg，深蹲1次最大重量[1RM]=163.5±28.6 kg；均值±标准差）参与了本研究，他们常规将后蹲纳入训练。跳蹲表现通过4种实验条件进行评估。第一种条件包括等于后蹲1RM的30%的等惯性负荷。其余条件包括分别在施加相当于后蹲1RM的20%、50%和80%的实验性增强离心负荷（AEL）条件后，进行向心负荷为1RM的30%的跳蹲。所有受试者按照平衡顺序在所有实验条件下进行2组最大努力跳蹲的1RM测试。在完成第一次测试 session 48小时后，受试者重复实验测试方案以建立稳定性可靠性。在向心跳蹲运动范围的初始400毫秒内，以20毫秒间隔获得的力量、速度和功率可靠变量的峰值表现值，以及力量和功率值，在实验性AEL负荷之间没有统计学差异（p>0.05）。这些结果表明，在进行1RM的30%的跳蹲之前进行负荷谱AEL并不能急性增强力量、速度和功率。
