The paper presents evaluation of human mobility by gait analysis, carried out in natural conditions (outside laboratory). Foot plantar pressure is measured using a shoe insole with 8 sensors placed in different anatomical zones of the foot, and placed inside a sports footwear. Polarized PVDF foil is used as a sensor material. A wireless transmission system is used to transmit voltage values to the computer. Due to linear relationship between force and transducer voltage, energy released during walking in arbitrary units can be calculated as integral of the square of transducer voltage over time. Gait measurements have been done over the next few days on healthy person during normal walking and slow walking. Performed measurements allow determination of walking speed (number of steps per second), gait rhythm and manner of walking (applying force to inside versus outside part of the sole). It is found that switching from normal to slow walk increases gait energy by 25% while the pressure distribution across the anatomical regions of the foot remains unchanged. The results will be used for developing a programme for evaluation of patients with cardiac failure and future integration of actimetry with pulse and spirometry measurements.
Measuring system designed and manufactured by the authors and based on mobile computers
(smartphones and tablets) working as data recorders has been invented to support diagnosis of orthopedic,
especially feet, diseases. The basic idea is to examine a patient in his natural environment, during the usual
activities (such as walking or running). The paper describes the proposed system with sensors manufactured
from piezoelectric film (PVDF film) and placed in the shoe insole. The mechanical reliability of PVDF film is
excellent, though elimination of the pyroelectric effect is required. A possible solution of the problem and the test
results are presented in the paper. Data recording is based on wireless transmission to a mobile device used as a