Reliability and Validity of Advanced Technologies: Kinotek’s 3D Motion Capture System in Functional Movement Assessments

Research Objectives: The purpose of this study was to investigate the reliability and concurrent validity of a one-camera markerless 3D motion analysis platform compared to a standard Goniometer, in assessing weight-bearing ankle dorsiflexion.

Design: Range of motion was assessed simultaneously by a one-camera markerless 3D motion capture system (Kinotek Inc, Portland, ME) and a standard Goniometer (small, 6-inch, full-circle). Two trials (test-retest) were recorded and used for data analysis. Inter-trial reliability was determined using the ICC (2,k) with 95% CI. The M, SD, and SEM were also analyzed for inter-trial consistency. Validity was determined using the Pearson Correlation Coefficient (r) using the averaged readings from both trials.

Setting: Following ethical approval, Hofstra University (Hempstead, NY).

Participants: Twenty-four healthy adults (mean age 29 ± 12 years; height 172.7 ± 10.2 cm; weight 70.3 ± 15 kg) participated in this study. Each participant was assessed bilaterally and provided two independent data points, right and left. Outliers were removed that were greater than two standard deviations from the mean, resulting in a sample of n=45 for data analysis.

Interventions: None.

Main Outcome Measures: No outcome measures were utilized in this study.

Results: The 3D motion capture yielded an ICC (95% CI) = 0.90 (0.82 – 0.94), and the Goniometer an ICC (95% CI) = 0.79 (0.65 – 0.88). Pearson Correlation r with 95% CI = 0.55 (.30 - .72) with statistical significance at p < .001. The M ±SD (SEM) with 95% CI: Kinotek 18.81 ±6.67 (.99), Goniometer 14.59 ±5.66 (.84)

Conclusions: Results from this study demonstrated a range from good-excellent reliability for the 3D motion capture system and moderate-good reliability for the Goniometer during a test-retest to assess ankle dorsiflexion during a weight-bearing lunge. The correlation was found to be in the moderate range with a large strength of association between the two instruments.

Author(s) Disclosures: Author(s) Disclosures: The authors disclose that Kaitlyn Haase is the Director of Research for Kinotek, Inc., and Dr. Ofra Pottorf is an independent research consultant and advisory board member for Kinotek, Inc.