Detection of Flight Phase in Race Walking Based on Pressure Sensors

Monitoring the flight phase in race walking is a crucial factor for training, planning and improvement of techniques for athletes in the field. The aim of this work was to develop an embedded system to detect the flight phase during race walking using pressure sensors and an user interface to visualize, analyze and store data. To evaluate the system, pressure data while standing vertical jumps (7 sequences of 10 jumps each) were registered with our system and simultaneously filmed using a camera at 24 frames per second in order to be contrasted using the Kinovea software. The proposed system measured an average flight time of $0.519 \pm 0.014\mathrm{s}$, while Kinovea presented an average of $0.515 \pm 0.009\mathrm{s}$. This showed that there is no significant difference between the two methods $( \mathrm{p}\gt 0.05)$. Subsequently, tests were conducted during 400 m race walking with a professional athlete throughout three tests, increasing the speed of execution (51 tests, 3 sequences of 17 repetitions each). The results showed an average flight time of 0.023, 0.025 and 0.054 s, according to the speed increase of the tests. Results of the tests show that the system supply reliable measurements with a largest relative error of 3.9% and that it could be an excellent tool for the monitoring and evaluation of race walking techniques.