Data from the sensors is collected at 100Hz. This means one-hundred measurements on each axis or each sensor per second; thats quite a lot of data. Rather than present measurements at 10ms resolution, data is aggregated into summary chunks. These chucks are called epochs and are 1-minute width.
That means every minute there is only one epoch measure per axis, but this measure contains information from 6000 samples (60 seconds * 100Hz).