Table 2.
Intraclass correlations and limits of agreement
| Gait variable | Absolute agreement: ICC(2,1) (95% CI) | Consistency: ICC(3,1) (95% CI) | Mean difference* (SD,% difference) | Limits of agreement 95% CI | |
|---|---|---|---|---|---|
| Lower | Upper | ||||
| Speed (cm/s) | 1.00 (1.00-1.00) | 1.00 (1.00-1.00) | 0.34 (0.59, 0.3%) | −0.82 | 1.50 |
| Cadence (steps/min) | 1.00 (1.00-1.00) | 1.00 (1.00-1.00) | −0.05 (0.19, 0.0%) | −0.42 | 0.33 |
| Stride length (cm) | 1.00 (1.00-1.00) | 1.00 (1.00-1.00) | 0.02 (0.38, 0.0%) | −0.73 | 0.76 |
| Step length (cm) | 1.00 (1.00-1.00) | 1.00 (1.00-1.00) | 0.02 (0.42, 0.0%) | −0.79 | 0.84 |
| Stride duration (s) | 1.00 (1.00-1.00) | 1.00 (1.00-1.00) | 0.000 (0.001, 0.0%) | −0.002 | 0.003 |
| Step duration (s) | 1.00 (1.00-1.00) | 1.00 (1.00-1.00) | 0.000 (0.004, −0.1%) | −0.008 | 0.007 |
| Stance duration (s) | 1.00 (1.00-1.00) | 1.00 (1.00-1.00) | 0.005 (0.009, 0.7%) | −0.012 | 0.022 |
| Swing duration (s) | 0.99 (0.99-1.00) | 1.00 (0.99-1.00) | −0.003 (0.005, −0.7%) | −0.013 | 0.007 |
| Double support duration (s) | 1.00 (0.99-1.00) | 1.00 (1.00-1.00) | 0.005 (0.010, 1.5%) | −0.014 | 0.025 |
| Stance time as a percentage of cycle time (%) | 1.00 (0.99-1.00) | 1.00 (0.99-1.00) | 0.22 (0.39, 0.3%) | −0.56 | 1.00 |
| Double support time as a percentage of cycle time (%) | 0.99 (0.99-1.00) | 1.00 (0.99-1.00) | 0.43 (0.89, 1.4%) | −1.31 | 2.17 |
| Base width (cm) | 0.86 (−0.03-0.96) | 0.97 (0.95-0.98) | −1.62 (0.82, −17.4%) | −3.22 | −0.02 |
| Foot angle (°) | 0.97 (0.89-0.99) | 0.98 (0.97-0.98) | 0.69 (0.95, 9.7%) | −1.18 | 2.56 |
| Variability (SD) in Stride Length (cm) | 0.95 (0.93-0.97) | 0.96 (0.94-0.97) | 0.01 (0.48. 3.6%) | −0.84 | 1.06 |
| Variability (SD) in Step Length (cm) | 0.84 (0.78-0.89) | 0.84 (0.78-0.89) | −0.01 (0.56, −0.5%) | −1.10 | 1.08 |
| Variability (SD) in Stride Duration (s) | 1.00 (0.99-1.00) | 1.00 (0.99-1.00) | 0.001 (0.003, 1.6%) | −0.006 | 0.007 |
| Variability (SD) in Step Duration (s) | 0.98 (0.97-0.98) | 0.98 (0.97-0.98) | −0.001 (0.005, −2.7%) | −0.009 | 0.008 |
| Variability (SD) in Step Width (cm) | 0.97 (0.95-0.98) | 0.98 (0.97-0.98) | 0.08 (0.20, 3.9%) | −0.32 | 0.47 |
ICC = Intraclass Correlation, CI = confidence interval, SD = standard deviation.
*Negative differences indicate GAITRite® higher than PKmas®.
ICC (2,1) absolute agreement, ICC(3,1) consistency (with 95% CI), mean difference (with SD and mean difference as a percentage of the mean GAITRite® value), and 95% limits of agreement for the total cohort. All ICCs were significant at p < 0.001.