Since the reactive strength index (RSI) and reactive strength index-modified (RSI-mod) share similar nomenclature, they are commonly referred as interchangeable measures of agility in the sports research literature. The RSI and RSI-mod are most commonly derived from the performance of depth jumping (DJ) and countermovement jumping (CMJ), respectively. Given that DJ and CMJ are plyometric movements that differ materially from biomechanical and neuromotor perspectives, it is likely that the RSI and RSI-mod measure distinct aspects of neuromuscular function. The purpose of this investigation was to evaluate the association and agreement between RSI and RSI-mod scores. A mixed-sex sample of NCAA division I basketball athletes (n = 21) and active young adults (n = 26) performed three trials of DJ from drop heights of 0.51, 0.66, and 0.81 m and three trials of countermovement jumping. Using 2-dimensional videography and force platform dynamometry, RSI and RSI-mod scores were estimated from DJ and CMJ trials, respectively. Linear regression revealed moderate associations between RSI and RSI-mod scores (F = 11.0–38.1; R² = 0.20–0.47; p < 0.001–0.001). Bland–Altman plots revealed significant measurement bias (0.50–0.57) between RSI and RSI-mod scores. Bland–Altman limit of agreement intervals (1.27–1.51) were greater than the mean values for RSI (0.97–1.05) and RSI-mod (0.42) scores, suggesting poor agreement. Moreover, there were significant performance-dependent effects on measurement bias, wherein the difference between and the mean of RSI and RSI-mod scores were positively associated (F = 77.2–108.4; R² = 0.63–0.71; p < 0.001). The results are evidence that the RSI and RSI-mod cannot be regarded as interchangeable measures of reactive strength.

中文翻译：

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反应强度指数与反应强度指数修正分数之间的关联和一致性

由于反应强度指数 (RSI) 和反应强度指数修正 (RSI-mod) 具有相似的命名法，因此它们在体育研究文献中通常被称为敏捷性的可互换度量。RSI 和 RSI-mod 最常分别来自于深度跳跃 (DJ) 和反向跳跃 (CMJ) 的表现。鉴于 DJ 和 CMJ 是增强式运动，与生物力学和神经运动的观点存在重大差异，RSI 和 RSI-mod 很可能测量神经肌肉功能的不同方面。本次调查的目的是评估 RSI 和 RSI-mod 分数之间的关联和一致性。NCAA I 级篮球运动员 ( n = 21) 和活跃的年轻人 ( n )的混合性别样本= 26) 从 0.51、0.66 和 0.81 m 的跌落高度进行了三项 DJ 试验和三项反向跳跃试验。使用二维摄像和力平台测力法，分别从 DJ 和 CMJ 试验中估计 RSI 和 RSI-mod 分数。线性回归显示 RSI 和 RSI-mod 分数之间存在中等关联（F = 11.0–38.1；R ² = 0.20–0.47；p< 0.001–0.001)。Bland-Altman 图显示 RSI 和 RSI-mod 分数之间存在显着的测量偏差 (0.50–0.57)。Bland-Altman 一致性区间极限 (1.27–1.51) 大于 RSI (0.97–1.05) 和 RSI-mod (0.42) 分数的平均值，表明一致性较差。此外，对测量偏差有显着的性能依赖影响，其中 RSI 和 RSI-mod 分数之间的差异和平均值呈正相关（F = 77.2–108.4；R ² = 0.63–0.71；p < 0.001）。结果证明 RSI 和 RSI-mod 不能被视为反应强度的可互换度量。