The motion state of a particle is a crucial aspect in sediment transport problems. In this paper, we conceptualized three states: stillness, ‘transport’ and ‘non-transport’. Starting from a data set of bed-load particle tracks obtained from Particle-Tracking-Velocimetry, we removed the bias from experimental uncertainty and applied one-dimensional, instantaneous and non-parametric criteria for distinguishing the different states. We present the distributions of particle velocity for all the moving states and separating the transport and non-transport states, fitting a literature model to them. The transport state is related to isotropic particle vibrations and does not significantly contribute to the bed-load rate. Vice-versa, the choice of accounting or not accounting for the non-transport state has major quantitative impact on the mean number of moving particles and mean particle velocity. Finally, the non-transport state has non-negligible contribution to the total kinetic energy of the bed-load particles.