Instrumented Shoes for 3D GRF Analysis and Characterization of Human Gait João P. Santos 1 , João P. Ferreira 1,2 , Manuel Crisóstomo 1(&) , and A. Paulo Coimbra 1 1 Institute of Systems and Robotics, Department of Electrical and Computer Engineering, University of Coimbra, Coimbra, Portugal mcris@isr.uc.pt 2 Department of Electrical Engineering, Superior Institute of Engineering of Coimbra, Coimbra, Portugal Abstract. The main objective of this work is to develop a computerized system based on instrumented shoes to characterize and analyze the human gait. The system uses instrumented shoes connected to a personal computer to provide the 3D Ground Reaction Forces (GRF) patterns of the human gait. This system will allow a much more objective understanding of the clinical evolution of patients, enabling a more effective functional rehabilitation of a patient’s gait. The sample rate of the acquisition system is 100 Hz and the system uses wireless communication. Keywords: Human gait analysis Á Gait pathologies Á Ground reaction forces 1 Introduction The study of the human gait has generated much interest in fields like biomechanics, robotics, and computer animation. It has been studied in medical science [1–3], psy- chology [4, 5], and biomechanics [6–8] for five decades. Comprehensive measures of gait pathology are useful in clinical practice. They allow stratification of severity, give an indication of the gait quality, and provide an evaluation of treatments outcomes. There are many ways to gauge overall gait pathology. While parent and caregiver assessments are useful and practical, they lack the precision and objectivity provided by three-dimensional quantitative gait data. Gait data can be used to assess pathology in a variety of ways. For example, stride parameters such as walking speed, step length, and cadence provide an overall picture of gait quality. These parameters are especially useful after normalization to account for differences in stature [9]. So, it’s important to have systems that provide such kind of information. To study and analyze the human gait, their patterns must be acquired. During walking, the most common force acting on the body is the GRF that is a three- dimensional force vector. The GRF consists of a vertical component plus two shear components, antero-posterior and medial-lateral directions, acting along the foot sup- port surface. A fourth variable is needed, the location of the center of pressure of this GRF vector. © Springer Nature Switzerland AG 2019 I. Rojas et al. (Eds.): IWBBIO 2019, LNBI 11466, pp. 51–62, 2019. https://doi.org/10.1007/978-3-030-17935-9_6