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

Ressman, John; Rasmussen-Barr, Eva; Grooten, Wilhelmus Johannes Andreas

doi:10.1186/s13102-020-00179-8

BMC Sports Science, Medicine and Rehabilitation

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

	Agreement^b		Diagnostic accuracy		Predictive values*		ROCⁱ
Cut off scores for index test^a	PA^c	Kappa^d (95% CI)	Sensitivity^e (95% CI)	Specificity^f (95% CI)	PPV^g (95% CI)	NPV^h (95% CI)	AUC^j (SE, 95% CI)
Qinematic™ 2°	0.75	0.47 (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°	0.77	0.51 (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°	0.80	0.55 (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°	0.83	0.57 (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°	0.84	0.57 (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°	0.82	0.50 (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°	0.85	0.58 (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°	0.86	0.57 (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°	0.85	0.54 (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°	0.83	0.45 (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)

Abbreviations: 95% CI 95% Confidence interval, SE Standard error
^aCut-of scores for index test Qinematic™: Qinematic™ 2° = Knee goes 2 degrees medial at the way down during a Single Leg Squat
^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
^cPA: Percent agreement
^dKappa: Cohens’ kappa, calculated by; \( \mathrm{K}=\frac{P_0-{P}_e}{1-{P}_e} \)
^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
^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
^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%
^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%
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)
^jAUC Area Under the Curve

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ISSN: 2052-1847

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