BACKGROUND The Poincaré plot method can be used for both qualitative and quantitative assessment of self-similarity in usually periodic functions, hence the idea of applying it to the study of homeostasis of living organisms. From the analysis of numerous scientific data, it can be concluded that hand functionality can be correlated with the state of the human body as a biological system exposed to various forms of ontogenetic stress. METHODS We used the Poincaré plot method to analyze the variability of hand grip strength (HGS), as an entropic biomarker of aging, during 60 repetitive tests of the dominant and nondominant hand, in young and older healthy subjects. An observational cross-sectional study was performed on 80 young adults (18-22 years old, mean age 20.01 years) and 80 older people (65-69 years old, mean age 67.13 years), with a sex ratio of 1:1 for both groups. For statistical analysis, we applied univariate descriptive statistics and inferential statistics (Shapiro-Wilk test, Mann-Whitney U-test for independent large samples, with the determination of the effect size coefficient r, and simple linear regression. We calculated the effect of fatigue and the Poincaré indices SD1, SD2, SD1/SD2 and the area of the fitting ellipse (AFE) for the test values of each subject. RESULTS The analysis of the differences between groups revealed statistically significant results for most HGS-derived indices (p ≤ 0.05), and the magnitude of the differences indicated, in most situations, a large effect size (r > 0.5). Our results demonstrate that the proposed repetitive HGS testing indicates relevant differences between young and older healthy subjects. Through the mathematical modeling of data and the application of the concept of entropy, we provide arguments supporting this new design of HGS testing. CONCLUSIONS Our results indicate that the variability of HGS during serial testing, which reflects complex repetitive biomechanical functions, represents an efficient indicator for differentiation between young and older hand function patterns from an entropic perspective. In practical terms, the variability of HGS, evaluated by the new serial testing design, can be considered an attractive and relatively simple biomarker to use for gerontological studies.

中文翻译：

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作为老化的熵生物标志物的系列测试过程中的握力强度变异性：庞加莱积图分析。

背景技术庞加莱图法可用于通常周期函数中自相似性的定性和定量评估，因此有将其应用于研究生物机体内稳态的想法。从大量科学数据的分析中可以得出结论，手的功能可以与人体的状态相关联，因为人体的生物系统暴露于各种形式的个体发育应激。方法我们使用Poincaré绘图法分析了年轻和年老健康受试者在60次重复测试中占主导地位和非主导地位的手的握力（HGS）的变异性，这是衰老的熵的生物标记。观察性横断面研究针对80位年轻人（18-22岁，平均年龄20.01岁）和80位老年人（65-69岁，平均年龄67.13岁）进行，两组的性别比均为1：1。为了进行统计分析，我们使用单变量描述性统计和推论统计（Shapiro-Wilk检验，Mann-Whitney U检验用于独立的大样本），并确定了效应大小系数r和简单的线性回归。我们计算了疲劳效应结果，各组之间的差异分析显示，大多数HGS衍生指标的统计学意义均显着（p≤ 0.05），并且差异的大小表明，在大多数情况下，效应的大小较大（r> 0.5）。我们的结果表明，所建议的重复性HGS测试表明，年轻人与老年人之间存在相关的差异。通过数据的数学建模和熵概念的应用，我们提供了支持这种HGS测试新设计的论据。结论我们的结果表明，从熵的角度看，HGS的变异性反映了复杂的重复生物力学功能，代表了区分年轻和较老的手功能模式的有效指标。实际上，通过新的系列测试设计评估的HGS变异性可以被认为是用于老年病学研究的有吸引力且相对简单的生物标记。它反映了复杂的重复生物力学功能，代表了从熵的角度区分年轻人和老年人手功能模式的有效指标。实际上，通过新的系列测试设计评估的HGS变异性可以被认为是用于老年病学研究的有吸引力且相对简单的生物标记。它反映了复杂的重复生物力学功能，代表了从熵的角度区分年轻人和老年人手功能模式的有效指标。实际上，通过新的系列测试设计评估的HGS变异性可以被认为是用于老年病学研究的有吸引力且相对简单的生物标记。