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Table 2 Results from the test-retest reliability study

From: Reliability and validity of a novel Kinect-based software program for measuring a single leg squat

 DataaDifferencesbRelative reliabilitycAbsolute reliability
T1
Median (Q1, Q3)
T2
Median (Q1, Q3)
GRAND
Median (Q1, Q3)
T1 vs. T2 p-valueSpearman (r) p-valueICC (3.1) (95% CI)SEMdSDCeMean difference between T2 and T1 with 95% confidence interval (95% CI)f
Left knee up (n = 64)−6.34 (−16.93, 6.26)0.66 (−8.40, 10.63)−2.53 (−11.53, 9.20)0.013*0.53 (0.002)0.50 (0.17 to 0 .72)10.6629.556.89 (1.98 to 11.81) *
Left knee down (n = 64)1.07 (−6.50, 19.42)0.80 (−9.50, 13.42)1.07 (−6.76, 15.48)0.54960.68 (< 0.001)0.69 (0.45 to 0.83)9.8527.30−2.15 (−7.19 to 2.89)
Right knee up (n = 61)−6.48 (−16.59, 7.09)−1.95 (−10.35, 7.87)−3.20 (−12.06, 7.09)0.20590.61 (< 0.001)0.69 (0.45 to 0.84)9.0425.062.83 (−1.91 to 7.56)
Right knee down (n = 62)0.59 (−11.71, 13.52)2.75 (−10.04, 12.59)2.27 (−10.04, 12.81)0.59670.61 (< 0.001)0.64 (0.38 to 0.81)9.0925.201.24 (−3.53 to 6.00)
  1. *Denotes a statistically significant change; n = denotes the number of measurements done by Qinematic™ for each variable; A negative value (−) denotes a medial displacement for the left knee and a lateral displacement for the right knee, contrariwise a positive value (+) denotes a medial displacement of the right knee and a lateral displacement for the left knee
  2. a Test occasion 1 = T1, Test occasion 2 = T2, Q1: 1st quartile (25%), Q3: 3rd (75%). Grand Median = median of all measures from test occasion 1 and 2. All data are in degrees
  3. b Wilcoxon signed-rank test (paired test). A p-value of p < 0.05 was considered to be statistically significant and marked with*
  4. c Reliability based on a two-way mixed effect model, calculating the absolute agreement, based on single ratings. ICC (3.1):\( {ICC}_{agreement}=\frac{\sigma_p^2}{\sigma_p^2+{\sigma}_o^2+{\sigma}_{residual}^2},{\sigma}_{error}^2={\sigma}_o^2+{\sigma}_{residual}^2 \)
  5. d SEM: Standard error of the measurement: \( {SEM}_{agreement}=\surd \left({\sigma}_o^2+{\sigma}_{residual}^2\right) \)
  6. e SDC: Smallest detectable change: SDC =  ± 1.96   √ 2 SEMagreement.
  7. f Mean difference between the two-test occasion was calculated together with the 95% confidence interval (95% CI). *A 95% CI that does not include zero indicates a systematic change in the mean between T1 and T2.