Table 1.

Concurrent validity of gait parameters measured by inertial measurement units (relative to optical motion capture)

Parameter	RMSE, mean (SD)	MAPE, %	Bias	LoA	RMSE, mean (SD)	MAPE, %	Bias	LoA
	SNP				PLHIV
Spatial parameters
Step length (cm)	3.22 (1.63)	1.66	− 1.05	− 5.83; 3.72	4.38 (2.01)	1.07	− 0.74	− 4.95; 3.47
Normalized step length	0.04 (0.02)	1.66	− 0.01	− 0.07; 0.04	0.05 (0.02)	1.07	− 0.01	− 0.05; 0.04
Stride length	4.46 (3.51)	2.51	− 3.26	− 11.45; 4.92	4.46 (2.62)	2.28	− 2.95	− 10.68; 4.78
Normalized stride length	0.05 (0.04)	2.51	− 0.04	− 0.13; 0.05	0.05 (0.03)	2.28	− 0.03	− 0.11; 0.05
Temporal parameters
Cadence (steps/min)	6.93 (4.41)	0.39	0.49	− 5.55; 6.54	6.15 (4.86)	0.18	0.01	− 4.75; 5.00
Stance time (s)	0.02 (0.01)	1.22	0.01	− 0.03; 0.04	0.03 (0.02)	1.06	0.01	− 0.04; 0.05
Step time (s)	0.03 (0.02)	0.12	< 0.00	− 0.03; 0.03	0.03 (0.02)	0.17	< 0.00	− 0.02; 0.02
Single support time (s)	0.02 (0.01)	1.21	− 0.01	− 0.03; 0.02	0.02 (0.01)	1.43	− 0.01	− 0.02; 0.01
Double support time (s)	0.03 (0.01)	7.40	0.01	− 0.04; 0.06	0.03 (0.03)	5.79	0.01	− 0.05; 0.07
Temporophasic parameters
Stance percentage (%GC)	1.72 (0.39)	0.98	0.57	− 1.37; 2.51	1.97 (1.23)	1.13	0.69	− 2.00; 3.43
Single support percentage (%GC)	2.44 (1.35)	1.37	− 0.57	− 3.53; 2.39	2.31 (1.40)	1.26	− 0.50	− 3.24; 2.24
Double support percentage (%GC)	3.01 (1.14)	6.96	1.14	− 3.58; 5.86	2.68 (2.29)	5.69	1.18	− 4.14; 6.51
Temporospatial parameters
Gait speed (m/s)	0.04 (0.03)	2.68	− 0.03	− 0.11; 0.04	0.04 (0.03)	2.13	− 0.03	− 0.10; 0.05
Normalized gait speed	0.01 (0.01)	2.68	− 0.01	− 0.04; 0.01	0.01 (0.01)	2.13	− 0.01	− 0.03; 0.02

MAPE mean absolute percentage error, GC gait cycle, LoA limits of agreement, PLHIV people living with HIV-1 infection, RMSE root-mean-square error, SNP HIV-seronegative participants