###### Abstract  
Incipient motion has been a topic of investigation by researchers, engineers and scientists for more than a century. The main approach for studying sediment entrainment has been the static approach that uses temporal and spatial averaged flow parameters like bed shear stress and stream power to link them indirectly to sediment entrainment. Recent research outputs have shed light on the important role of turbulent fluctuations in the sediment transport process. It is suggested that the approach of using temporal and spatial averaged parameters fails to account for the dynamic and probabilistic nature of the entrainment process, as inherited by flow turbulence. This has led to the introduction of the only dynamic criteria in the literature for studying sediment entrainment, namely the impulse and energy criteria. These criteria take into account both the magnitude and duration of the turbulent flow event used for assessing the conditions that can result in sediment entrainment. In light of this, this work aims to assess whether there is a trend in terms of the type of flow structures that occur in sequence before and after the occurrences of the flow impulses that have resulted in the coarse particle's entrainment. To achieve this, we conducted a well-controlled laboratory experiment to investigate the incipient motion of a 7 cm diameter instrumented particle. Five runs of the experiment were performed at flowrates close to the threshold of motion. The instrumented particle was equipped with micro-electro-mechanical sensors (MEMS) to accurately measure its inertial dynamics and detect motion. The sensors recorded entrainment events, and these events were stochastically linked to the impulses occurring for the tested flow conditions. Quadrant analysis was used to investigate the type of flow structures that occurred before, during and after the occurrence of quadrant events with an impulse above the critical impulse. The findings herein associate coarse particle entrainments with energetic impulses linked primarily to sweep events (\(Q_{d}\)) and secondarily, sequence of sweeps (\(Q_{d}\)) and ejections (\(Q_{1}\)). os 2023 13 2023 13 September 2  
and the dynamic approach. The static approach uses time-averaged parameters like bed shear stress [4] or critical stream power [5; 6] to define the conditions that result in sediment entrainment. Since turbulence by definition is chaotic and random around the averaged values of pressure or velocity [7], multiple researchers [8; 9; 10; 11; 12; 13; 14] have tried to emphasise the important role of turbulent fluctuations in the sediment transport process in an attempt to overcome the limitations of the time-averaged parameters approach or the static approach. Some researchers have reported that increasing the turbulence level in the boundary layer while maintaining the same time-averaged shear stress in the boundary layer has resulted in an increase in bed-load transport rates [15; 16]. Other researchers [17; 18] have suggested that instantaneous normal Reynolds shear stresses are more correlated with sediment movement compared to average or instantaneous shear stresses. Thereafter, [19] suggested that both the force magnitude and duration of the energy near to the bed turbulent events are relevant when predicting sediment entrainment. He also introduced the impulse criterion, which is the first dynamic criterion used for studying sediment entrainment reported in the literature. [PERSON] et al. [20] and [PERSON] et al. [21] generalised the applicability of the concept and [PERSON] et al. [22] extended it to the energy criterion which is the second dynamic criterion that exists in the literature for assessing the conditions that can result in sediment entrainment. The energy criterion formulates that the complete removal of sediment from the bed matrix occurs only if the impinging flow event(s) supply enough mechanical energy.