Table 2.

Comparison of force and center of pressure errors. Errors are shown in terms of root-mean-square (rms) magnitude, the worst axis of the force plate, and the rms error in the direction of the worst axis. The worst axis is either anterior-posterior (AP), medial-lateral (ML), or vertical (V), with the long axis of each force plate aligned with the AP direction. Results are shown for standard flush-mounted force plates (FP) and for force treadmills (FTM).

	Lewis [12]	PILS	Kram [5]	Dierick [8]	Black [15]	PILS
Parameter	FP	FP	FTM	FTM	FTM	FTM
Force error
rms mag.	4.3%	1.4%	-	2.4%	1.7%	1.4%
worst axis	V	AP	-	AP	-	ML
rms worst axis	2.7%	3.1%	-	2.1%	-	3.6%
Static COP
rms mag.	0.009 m	0.003 m	0.008 m	0.042 m	0.003 m	0.005 m
worst axis	AP	ML	ML	AP	-	AP
rms worst axis	0.008 m	0.002 m	0.006 m	0.042 m	-	0.004 m
Dynamic COP
rms mag.	-	-	0.010 m	-	0.006 m	0.008 m