Table 2.

Bland–Altman agreement results of spatiotemporal variables between motion capture system and smartphone application

Gait conditions	Mean bias	95% CI mean bias	Upper limit agreement	95% CI upper limit agreement	Lower limit agreement	95% CI lower limit agreement
Pooled gait conditions
Double limb stance time	− 0.010	− 0.015, − 0.005	0.037	0.028, 0.046	− 0.058	− 0.067, − 0.049
Single limb stance time	− 0.001	− 0.003, 0.002	0.026	0.021, 0.031	− 0.028	− 0.033, − 0.022
Step length	− 0.032	− 0.045, − 0.019	0.083	0.061, 0.106	− 0.149	− 0.172, − 0.127
Cadence	− 0.019	− 0.046, 0.006	0.218	0.172, 0.264	− 0.258	− 0.304, − 0.212
Stride length	− 0.091	− 0.111, − 0.071	0.088	0.054, 0.123	− 0.271	− 0.306, − 0.236
Swing time	0.001	− 0.002, 0.003	0.027	0.022, 0.032	− 0.026	− 0.031, − 0.020
Gait speed	− 0.095	− 0.433, 0.102	0.122	0.080, 0.164	− 0.312	− 0.354, − 0.270
Self-selected gait speed
Double limb stance time	− 0.014	− 0.026, − 0.002	0.038	0.016, 0.059	− 0.067	− 0.088, − 0.045
Single limb stance time	− 0.002	− 0.009, 0.003	0.024	0.013, 0.036	− 0.030	− 0.041, − 0.019
Step length	− 0.045	− 0.067, − 0.024	0.045	0.008, 0.082	− 0.136	− 0.173, − 0.099
Cadence	− 0.014	− 0.036, 0.008	0.080	0.042, 0.119	− 0.109	− 0.147, − 0.070
Stride length	− 0.104	− 0.133, − 0.075	0.019	− 0.030, 0.069	− 0.227	− 0.277, − 0.177
Swing time	0.003	− 0.003, 0.009	0.030	0.019, 0.041	− 0.024	− 0.035, − 0.013
Gait speed	− 0.102	− 0.129, 0.074	0.016	− 0.031, 0.065	− 0.221	− 0.269, − 0.172
Fixed gait speed 0.8 m/s
Double limb stance time	− 0.021	− 0.032, − 0.011	0.021	0.003, 0.039	− 0.065	− 0.083, − 0.047
Single limb stance time	− 0.006	− 0.012, − 0.000	0.020	0.009, 0.031	− 0.033	− 0.043, − 0.022
Step length	0.004	− 0.010, 0.019	0.068	0.042, 0.094	− 0.059	− 0.085, − 0.033
Cadence	− 0.003	− 0.023, 0.017	0.084	0.048, 0.119	− 0.090	− 0.125, − 0.054
Stride length	− 0.014	− 0.033, 0.003	0.064	0.032, 0.096	− 0.093	− 0.125, − 0.061
Swing time	0.006	0.000, 0.012	0.032	0.021, 0.042	− 0.019	− 0.029, − 0.008
Gait speed	− 0.011	− 0.027, 0.005	0.059	0.030, 0.088	− 0.081	− 0.110, − 0.053
Fixed gait speed 2.0 m/s
Double limb stance time	0.008	0.001, 0.017	0.043	0.029, 0.057	− 0.025	− 0.040, − 0.011
Single limb stance time	0.009	0.004, 0.013	0.029	0.021, 0.037	− 0.011	− 0.019, − 0.002
Step length	− 0.061	− 0.098, − 0.023	0.099	0.034, 0.163	− 0.221	− 0.286, − 0.156
Cadence	− 0.074	− 0.176, 0.028	0.362	0.185, 0.539	− 0.511	− 0.688, − 0.334
Stride length	− 0.172	− 0.218, − 0.126	0.022	− 0.056, 0.102	− 0.367	− 0.446, − 0.288
Swing time	− 0.008	− 0.013, − 0.004	0.010	0.002, 0.018	− 0.028	− 0.036, − 0.020
Gait speed	− 0.196	− 0.245, − 0.147	0.089	− 0.026, 0.205	− 0.483	− 0.599, − 0.367
Self-selected gait speed and dual task
Double limb stance time	− 0.014	− 0.022, − 0.005	0.022	0.007, 0.037	− 0.051	− 0.066, − 0.036
Single limb stance time	− 0.003	− 0.009, 0.002	0.021	0.011, 0.031	− 0.027	− 0.037, − 0.018
Step length	− 0.029	− 0.051, − 0.007	0.063	0.025, 0.100	− 0.121	− 0.159, − 0.084
Cadence	0.012	− 0.011, 0.036	0.116	0.074, 0.158	− 0.091	− 0.133, − 0.049
Stride length	− 0.074	− 0.108, − 0.040	0.070	0.011, 0.129	− 0.220	− 0.279, − 0.161
Swing time	0.002	− 0.003, 0.008	0.027	0.017, 0.037	− 0.022	− 0.032, − 0.012
Gait speed	− 0.070	− 0.102, − 0.037	0.069	0.012, 0.126	− 0.210	− 0.266, − 0.153

A positive mean bias value indicates the smartphone application (OneStep) overestimated the variable compared to the motion capture system (Vicon). A negative mean bias value indicates the smartphone application underestimated the variable compared to the motion capture system