Wireless electrocardiograms (WECGs) allow long-term monitoring of patients in their residential and work environments. However, the measurements are easily affected by motion artifacts. To reason about and remove the artifacts, reference models (signals) are needed. One way to construct these models is by employing motion sensors that pick up the motion affecting the electrodes of a WECG. In this paper, we experimentally examine the existence of correlations between the measurements of inertial sensors and motion artifacts. We employed three reference sensor types (3D accelerometer, 3D gyroscope, and skin impedance sensor). Our analysis includes actual measurements taken from eleven healthy subjects carrying out six different movements: Stand up, bend forward, walking, running, jumping and climbing stairs. We found that the best place to attach inertial sensors is the sternum of the torso. Although all three sensor types exhibit comparable levels of correlation to isolated motion artifacts, the gyroscope performs best in removing motion artifacts with an adaptive filter.