McMahon John J, Suchomel Timothy J, Lake Jason P, Comfort Paul
Directorate of Sport, Exercise and Physiotherapy, University of Salford, Greater Manchester, United Kingdom.
Department of Human Movement Sciences, Carroll University, Waukesha, Wisconsin; and.
J Strength Cond Res. 2021 Jan 1;35(1):280-285. doi: 10.1519/JSC.0000000000002462.
McMahon, JJ, Suchomel, TJ, Lake, JP, and Comfort, P. Relationship between reactive strength index variants in rugby league players. J Strength Cond Res 35(1): 280-285, 2021-Two reactive strength index (RSI) variants exist, the RSI and RSI modified (RSImod), which are typically calculated during the drop jump (DJ) and countermovement jump (CMJ), respectively. Both RSI variants have been used to monitor athletes' ability to complete stretch-shortening cycle actions quickly, but they have never been compared. The purpose of this study was to determine whether they yield relatable information about reactive strength characteristics. Male professional rugby league players (n = 21, age = 20.8 ± 2.3 years, height = 1.82 ± 0.06 m and body mass = 94.3 ± 8.4 kg) performed 3 DJs (30 cm) and CMJs on a force plate. Reactive strength index and RSImod were subsequently calculated by dividing jump height (JH) by ground contact time (GCT) and time to take-off (TTT), respectively. All variables were highly reliable (intraclass correlation coefficient ≥0.78) with acceptable levels of variability (coefficient of variation ≤8.2%), albeit larger variability was noted for DJ variables. Moreover, there was a large relationship between RSI and RSImod (r = 0.524, p = 0.007), whereas very large relationships were noted between JHs (r = 0.762, p < 0.001) and between GCT and TTT (ρ = 0.705, p < 0.001). In addition, RSI (0.90 ± 0.22) was largely and significantly (d = 2.57, p < 0.001) greater than RSImod (0.47 ± 0.08). The DJ-derived RSI yields much larger values than the CMJ-derived RSImod and although a large relationship was noted between them, it equated to just 22% shared variance. These results suggest that the 2 RSI variants do not explain each other well, indicating that they do not assess entirely the same reactive strength qualities and should not be used interchangeably.
麦克马洪，JJ；苏乔梅尔，TJ；莱克，JP；以及康福特，P。橄榄球联盟运动员反应力量指数变体之间的关系。《力量与体能研究杂志》35(1): 280 - 285，2021年 - 存在两种反应力量指数（RSI）变体，即RSI和改良反应力量指数（RSImod），它们通常分别在深蹲跳（DJ）和反向纵跳（CMJ）过程中计算得出。两种RSI变体都已被用于监测运动员快速完成拉伸 - 缩短周期动作的能力，但它们从未被比较过。本研究的目的是确定它们是否能提供关于反应力量特征的相关信息。男性职业橄榄球联盟运动员（n = 21，年龄 = 20.8 ± 2.3岁，身高 = 1.82 ± 0.06米，体重 = 94.3 ± 8.4千克）在测力台上进行了3次深蹲跳（30厘米）和反向纵跳。随后，分别通过将跳高技术（JH）除以地面接触时间（GCT）和起跳时间（TTT）来计算反应力量指数和改良反应力量指数。所有变量的可靠性都很高（组内相关系数≥0.78），变异水平可接受（变异系数≤8.2%），尽管深蹲跳变量的变异更大。此外，RSI和RSImod之间存在较大关系（r = 0.524，p = 0.007），而跳高技术之间（r = 0.762，p < 0.001）以及地面接触时间和起跳时间之间（ρ = 0.705，p < 0.001）存在非常大的关系。此外，RSI（0.90 ± 0.22）在很大程度上且显著地（d = 2.57，p < 0.001）大于RSImod（0.47 ± 0.08）。源自深蹲跳的RSI产生的值比源自反向纵跳的RSImod大得多，尽管它们之间存在较大关系，但这仅相当于22%的共同方差。这些结果表明，这两种RSI变体不能很好地相互解释，这表明它们并未完全评估相同的反应力量素质，不应互换使用。
