The existence of a learning effect by which subjects progressively reduce body sway over the course of repetitive stabilometric measurements is currently debated. Also, the position and orientation of the feet on the platform can have a substantial influence on the outcome measurements. The aim of the present work was to assess the effect of feet positions on mean total velocity (V) of the center of pressure and the area (AR) covered by its displacements during quiet standing. A group of 35 healthy young subjects was examined during two successive sessions consisting of five recordings with their feet placed either in the recommended (standard, SP) or their usual most comfortable (UP) position. Results show a slight decreasing trend that failed to be statistically significant checked with Friedman's ANOVA (SP AR, χ2(4)=6.10, p=0.19 and V, χ2(4)=8.66, p=0.07 and UP AR, χ2(4)=2.32, p=0.68 and V, χ2(4)=1.19, p=0.88). Nonetheless, values of AR and V showed a notable decrement especially evident in the SP exam reaching, respectively, 24% and 11% from baseline, whereas variability measured by the coefficient of variation was the same in the two exams. Given the results, a learning effect should not be ruled out with confidence. Also, usual foot placement would be preferable to avoid this effect. Further research is needed to take into consideration the great variability of stabilometric measurements and the fact that different subjects could adapt more readily to the test conditions than others.

中文翻译：

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稳定性测量的学习效果和可重复性：“标准”与通常的足部放置。

受试者在重复稳定性测量过程中逐渐减少身体摇摆的学习效应的存在目前正在争论中。此外，脚在平台上的位置和方向会对结果测量产生重大影响。本工作的目的是评估脚的位置对压力中心的平均总速度 (V) 及其在安静站立时位移所覆盖的面积 (AR) 的影响。一组 35 名健康的年轻受试者在连续两次会议期间接受了检查，包括五次录音，他们的脚放在推荐的（标准，SP）或他们通常最舒适的（UP）位置。结果显示略有下降趋势，未能通过弗里德曼方差分析（SPAR，χ2(4)=6.10，p=0.19 和 V，χ2(4)=8.66, p=0.07 和 UP AR, χ2(4)=2.32, p=0.68 和 V, χ2(4)=1.19, p=0.88)。尽管如此，AR 和 V 的值显示出显着的下降，在 SP 考试中尤为明显，分别达到了基线的 24% 和 11%，而通过变异系数衡量的变异性在两个考试中是相同的。鉴于结果，不应充满信心地排除学习效果。此外，为了避免这种影响，通常的脚放置会更可取。需要进一步研究以考虑稳定性测量的巨大可变性以及不同受试者比其他受试者更容易适应测试条件的事实。与基线相比分别为 24% 和 11%，而通过变异系数衡量的变异性在两次考试中是相同的。鉴于结果，不应充满信心地排除学习效果。此外，为了避免这种影响，通常的脚放置会更可取。需要进一步研究以考虑稳定性测量的巨大可变性以及不同受试者比其他受试者更容易适应测试条件的事实。与基线分别相差 24% 和 11%，而通过变异系数衡量的变异性在两次考试中是相同的。鉴于结果，不应充满信心地排除学习效果。此外，为了避免这种影响，通常的脚放置会更可取。需要进一步研究以考虑稳定性测量的巨大可变性以及不同受试者比其他受试者更容易适应测试条件的事实。