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Reliability and Concurrent Validity of a Markerless, Single Camera, Portable 3D Motion Capture System for Assessment
Ofra Pottorf1, Daniel Vapne2, Jamie Ghigiarelli1
1Allied Health and Kinesiology Hofstra University.
Introduction:
Recent technological advancements have enabled medical, sport, and fitness professionals to utilize digital tools that assist with conducting movement examinations and screenings. One such advancement has been the implementation of a single camera, markerless, and portable 3D motion capture system designed to obtain ROM measurements for multiple body parts simultaneously. However, the reliability and validity of a markerless 3D motion capture system that uses a single camera has not been established.
Purpose:
The purpose of this study was to investigate the reliability and concurrent validity of this 3D motion capture system compared to a goniometer in assessing ROM of the glenohumeral joint.
Study Design:
Quasi-experimental reliability, convenience sampling.
Methods/Materials:
Forty healthy volunteers (mean ± SD, age 27.4 ± 12.4 years, height 173.4 ± 11.1 cm, weight 72.1 ± 16.2 kg) participated in this study. Intrarater reliability was analyzed by ICC(2,k) with a 95% CI using two repeated trials for each shoulder movement (flexion, abduction, external rotation, internal rotation) that were recorded simultaneously via two methods: a standard goniometer and a 3D motion capture system. Concurrent validity was analyzed using Pearson Correlation Coefficient (r).
Results:
The intrarater reliability between the two instruments for glenohumeral motions yielded an overall ICC of 0.82 (95% CI: 0.74-0.88) indicating good reliability for both instruments.The 3D motion capture system demonstrated strong correlations with goniometry for shoulder flexion (r = 0.67), abduction (r = 0.63), and external rotation (r = 0.76), and very strong correlation for shoulder internal rotation (r = 0.84).
Conclusion:
Results from this study indicated that a markerless, single camera, portable 3D motion capture system can be a reliable and valid tool to assess glenohumeral joint ROM in comparison to a standard goniometer.
Level Of Evidence:
3.
