BACKGROUND Bioelectrical impedance analysis (BIA) is a popular technique which can be used to track longitudinal changes in body composition. However, precision of the technique has been questioned, especially among athletic populations where small but meaningful changes are often observed. Guidelines exist which attempt to optimize precision of the technique but fail to account for potentially important variables. Standardization of dietary intake and physical activity in the 24 hr prior to assessment has been proposed as an approach to minimizing the error of impedance-derived estimates of body composition. METHODS Eighteen recreational athletes, male (n = 10) and female (n = 8), underwent two consecutive BIA tests to quantify within-day error, and a third test (the day before or after) to quantify between-day error. All food and fluid intake plus physical activity from the 24 hr prior to the first BIA scan was replicated during the following 24 hr. Precision error was calculated as the root mean square standard deviation, percentage coefficient of variation, and least significant change. RESULTS There were no significant differences in precision error of within- and between-day fat-free mass, fat mass, and total body water. Differences in precision error of fat-free mass and total body water, but not fat mass, were less than the smallest effect size of interest. CONCLUSION The 24-hr standardization of dietary intake and physical activity may be an effective approach to minimizing precision error associated with BIA. However, further research to confirm the validity of this protocol compared to nonstandardized or randomized intake is warranted.

中文翻译：

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协议标准化可以提高 InBody 720 身体成分分析的精度误差。

背景技术生物电阻抗分析(BIA)是一种流行的技术，其可用于追踪身体成分的纵向变化。然而，该技术的精确度受到质疑，特别是在运动人群中，经常观察到微小但有意义的变化。现有的指南试图优化技术的精度，但未能考虑潜在的重要变量。评估前 24 小时内的饮食摄入量和体力活动的标准化已被提议作为最大限度地减少由阻抗得出的身体成分估计误差的方法。方法 18 名休闲运动员，男性（n = 10）和女性（n = 8），接受了两次连续的 BIA 测试来量化日内误差，并进行第三次测试（前一天或后一天）来量化日间误差。在接下来的 24 小时内重复第一次 BIA 扫描前 24 小时的所有食物和液体摄入量以及体力活动。精度误差计算为均方根标准差、变异百分比系数和最小显着变化。结果 日内和日间去脂体重、脂肪质量和体内水分总量的精密误差没有显着差异。除脂肪质量和体内总水分（而非脂肪质量）的精确误差差异小于感兴趣的最小效应量。结论 膳食摄入和体力活动的 24 小时标准化可能是最小化与 BIA 相关的精度误差的有效方法。然而，需要进一步研究来确认该方案与非标准化或随机摄入相比的有效性。