Gross T S, Bunch R P
Biomechanics Laboratory, Converse, Inc., North Reading, MA 01864.
J Biomed Eng. 1988 May;10(3):261-5. doi: 10.1016/0141-5425(88)90008-8.
The purpose of this investigation was to design and validate a system suitable for non-invasive measurement of discrete in-shoe vertical plantar stress during dynamic activities. Eight transducers were constructed, with small piezoelectric ceramic squares (4.83 x 4.83 x 1.3 mm) used to generate a charge output proportional to vertical plantar stress. The mechanical properties of the transducers included 2.3% linearity and 3.7% hysteresis for stresses up to 2000 kPa and loading times up to 200 ms. System design efficacy was analysed by means of a multiple day, multiple trial data collection. With the transducers placed beneath plantar landmarks, the footstrike of one subject was recorded ten times on each of five days while running at 3.58 m/s on a treadmill. Within-day and between-day proportional error (PE) was used to estimate the error contained in the mean peak stress during foot contact. Within-day PE focused on trial to trial variability associated with the subject and equipment, and averaged 3.1% (range 2.5-4.0%) across transducer location. Between-day PE provided a cumulative estimate of subject, transducer placement, and random equipment variability, but excluded trial to trial variability. It ranged from 4.9 to 15.8%, with a mean of 9.9%. Peak stress, impulse, and sequence of loading data were examined to identify discrete foot function patterns and highlight the value of discrete stress analysis.
本研究的目的是设计并验证一种适用于在动态活动期间对离散的鞋内垂直足底压力进行无创测量的系统。制作了八个传感器，使用小型压电陶瓷方块（4.83×4.83×1.3毫米）来产生与垂直足底压力成比例的电荷输出。对于高达2000 kPa的应力和长达200 ms的加载时间，传感器的机械性能包括2.3%的线性度和3.7%的滞后现象。通过多天、多次试验的数据收集来分析系统设计的有效性。将传感器放置在足底标志下方，在跑步机上以3.58米/秒的速度跑步时，在五天中的每一天对一名受试者的足部撞击进行十次记录。日内和日间比例误差（PE）用于估计足部接触期间平均峰值应力中包含的误差。日内PE关注与受试者和设备相关的试验间变异性，跨传感器位置平均为3.1%（范围2.5 - 4.0%）。日间PE提供了受试者、传感器放置和随机设备变异性的累积估计，但排除了试验间变异性。其范围为4.9%至15.8%，平均值为9.9%。检查峰值应力、冲量和加载数据序列，以识别离散的足部功能模式并突出离散应力分析的价值。
