The detection performance of a walk-through metal detector (WTMD) is affected not only by the electromagnetic properties and size and shape of the test objects, but potentially also by the type of motion of the test object through the portal of the WTMD. This motion, it has been argued, can contribute to the uncertainty in detecting threat objects being carried through the WTMD. Typical laboratory-based testing uses a robotic system, or similar, to push a test object through the portal with a trajectory that is a straight line and has a constant velocity. This testing, although reproducible and accurate, does not test for those trajectories the are representative of natural body motion. We report the effects of nonrectilinear trajectories on the detection performance of WTMDs.