Biomedical Signal Analysis by a Low-cost Accelerometer Measurement System

Movement functional analysis of vertical jump allows to quantify the motor capabilities of lower limbs and so to determine the performance level and the effectiveness of the trial programs. Force platforms and stereophotogrammetric systems are the reference instruments, but they cannot be used in "non-structured" environments. In this study a novel measurement system, able to give objective performance indication about motor capabilities of subject involved in vertical jumping ,has been developed and validated. It is based on a low-cost, small and low-weight triaxial accelerometer, a portable datalogger and a suitable analyzing software. The realized system presents ±10g FSR and 78 mg resolution and has been employed in the acquisition of vertical jump performed by 124 subjects. The acceleration signal has been processed by a dedicated algorithm for the estimation of flight time. The results have been compared to the same parameter, calculated using the Ground Reaction Force (GRF) given by a force platform. The flight time, measured by acceleration and GRF, presents a good correlation (0,96) and a percent error of 4,2% and allows to discriminate the high jump performance between athletes and normal subjects (p<0,01)