TABLE I.

RMSE of internal marker trajectories over five consecutive measurements and corresponding range of motion.

	RMSE (mm)		Range of motion (mm)
Internal marker	SI	AP	SI	AP
1	0.24	0.08	10.89	2.17
2	0.21	0.08	9.31	2.44
3	0.09	0.08	2.31	0.53
4	0.09	0.06	3.72	1.72
5	0.15	0.25	1.43	1.48
6	0.10	0.10	2.17	1.13