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Table 3 Results from the construct validity study

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

 AgreementbDiagnostic accuracyPredictive values*ROCi
Cut off scores for index testaPAcKappad (95% CI)Sensitivitye (95% CI)Specificityf (95% CI)PPVg (95% CI)NPVh (95% CI)AUCj (SE, 95% CI)
Qinematic™ 2°0.750.47 (0.30 to 0.64)0.90 (0.73 to 0.98)0.69 (0.58 to 0.79)0.51 (0.42 to 0.60)0.95 (0.86 to 0.98)0.79 (0.04, 0.72 to 0.87)
Qinematic™ 4°0.770.51 (0.34 to 0.68)0.86 (0.68 to 0.96)0.74 (0.63 to 0.83)0.54 (0.45 to 0.64)0.94 (0.86 to 0.97)0.80 (0.04, 0.72 to 0.88)
Qinematic™ 6°0.800.55 (0.39 to 0.73)0.86 (0.68 to 0.96)0.78 (0.67 to 0.86)0.58 (0.47 to 0.68)0.94 (0.86 to 0.98)0.82 (0.04, 0.74 to 0.90)
Qinematic™ 8°0.830.57 (0.39 to 0.75)0.72 (0.53 to 0.87)0.86 (0.77 to 0.93)0.66 (0.51 to 0.78)0.90 (0.83 to 0.94)0.79 (0.05, 0.70 to 0.89)
Qinematic™ 10°0.840.57 (0.39 to 0.75)0.66 (0.46 to 0.82)0.90 (0.82 to 0.96)0.70 (0.54 to 0.83)0.88 (0.82 to 0.92)0.78 (0.05, 0.68 to 0.87)
Qinematic™ 12°0.820.50 (0.30 to 0.70)0.55 (0.36 to 0.73)0.91 (0.83 to 0.97)0.70 (0.51 to 0.83)0.85 (0.79 to 0.90)0.73 (0.05, 0.65 to 0.83)
Qinematic™ 14°0.850.58 (0.39 to 0.77)55.17 (0.36 to 0.74)0.96 (0.90 to 0.99)0.84 (0.63 to 0.94)0.86 (0.80 to 0.90)0.76 (0.05, 0.66 to 0.85)
Qinematic™ 16°0.860.57 (0.37 to 0.76)0.52 (0.33 to 0.71)0.98 (0.91 to 1.0)0.88 (0.65 to 0.97)0.85 (0.80 to 0.89)0.75 (0.05, 0.65 to 0.84)
Qinematic™ 18°0.850.54 (0.33 to 0.74)0.48 (0.30 to 0.68)0.98 (0.91 to 1.0)0.88 (0.63 to 0.97)0.84 (0.79 to 0.88)0.73 (0.05, 0.64 to 0.82)
Qinematic™ 20°0.830.45 (0.23 to 0.68)0.38 (0.21 to 0.58)0.99 (0.93 to 1.00)0.92 (0.60 to 0.99)0.82 (0.77 to 0.86)0.68 (0.05, 0.59 to 0.77)
  1. Abbreviations: 95% CI 95% Confidence interval, SE Standard error
  2. aCut-of scores for index test Qinematic™: Qinematic™ 2° = Knee goes 2 degrees medial at the way down during a Single Leg Squat
  3. bAgreement: Agreement of the visual assessed Single Leg Squat and the measures of Qinematic™ at different cut-off scores for medial displacement of the knee
  4. cPA: Percent agreement
  5. dKappa: Cohens’ kappa, calculated by; \( \mathrm{K}=\frac{P_0-{P}_e}{1-{P}_e} \)
  6. eSensitivity: Probability that Qinematic™ exceeds the given cut-of score when the subjects are assessed as having a knee-medial-to-foot position, a true positive rate
  7. fSpecificity: Probability that Qinematic™ doesn’t exceed the given cut-of score when the subjects are assessed as having a knee over-foot position, a true negative rate
  8. gPositive predictive value: Probability that the subjects are assessed as having a knee-medial-to-foot position when Qinematic™ exceeds the given cut-of score. *The prevalence of having a “knee-medial-to-foot position” in the investigated population are 27%
  9. hNegative predictive value: Probability that the subjects are assessed as having a knee-over-foot position when Qinematic™ doesn’t exceed the given cut of score. *The prevalence of having a “knee-medial-to-foot position” in the investigated population are 27%
  10. iROC Receiver Operating Characteristics in which the true positive value (sensitivity on Y-axis) is plotted against the false positive value (1-specificity on X-axis)
  11. jAUC Area Under the Curve