The invention relates to a magnetic resonance (MR) system for acquiring MR data from a subject (105), the MR system comprising a monitoring module (117) for monitoring a characteristic of a motion of the subject, the characteristic of the motion having a pre-determined or dynamically adjusted limit (119), and a pulse sequencer (108) for applying a pulse sequence to acquire data from the subject (105) when the characteristic of the motion is within the limit (119), the pulse sequence comprising at least one pulse waveform, wherein the pulse sequencer (108) is further arranged to regulate a characteristic of the at least one pulse waveform when the characteristic of the motion surpasses the limit (119).