This paper presents a method to calculate spatiotemporal parameters using a chest-worn accelerometer. Accuracy was compared with an optical system that consists of a walkway of transmitting and receiving bars (Microgait, Optogait, Bolzano, Italy). To this purpose, seventeen healthy male wore a smart shirt based worn accelerometer performing five meters of walkway delimited by five meters of optical bars OptoGait™ for three times. Spatiotemporal parameters such as gait cycle and gait phases were analysed and compared using the two systems. Smart shirt based on chest-worn accelerometer revealed to be a non-intrusive way of calculating gait cycle, phases and sub-phases. In addition, the inverted pendulum model based on chest body-worn accelerometer revealed to be a good model for calculating step length variation and consequently the speed. Our results, are in line with previous literature presenting an average of 60.24% of stance phase, 39.75% of swing phase, a foot flat subphase of 17.60%, a terminal stance subphase of 21.42%, a pre-swing subphase of 10.65%, a step length of 0.74 m for an average speed of 1.37 m/s using the smart shirt.