Background: Rolling is an important developmental milestone for infants where identifying the coordinated movement patterns could facilitate the early identification of motor development delays. Current methods for identifying coordinated movements of rolling are limited to a laboratory setting and not feasible for clinicians.
Objective: To develop video-based methods in which six coordinated movements, previously defined through motion capture, can be identified through video alone.
Methods: Forty-five videos of sixteen healthy infants achieving a roll were used to develop the video-based methodology and twenty-four videos had corresponding motion capture data used for validation. Four raters comprised of researchers and a clinician identified rolling coordination using the new video-based methods. A Fleiss' Kappa statistical test determined the inter- and intra-rater reliability of agreement for the new methodology and compared it to motion capture.
Results: The comparison of the motion capture and video-based methods resulted in substantial agreement. The video-based methods inter- and intra-rater reliability were substantial and almost perfect, respectively.
Conclusions: We developed reliable methodology to accurately identify the coordinated movements of infant rolling using only 2D video. This methodology will allow researchers to reliably define coordinated movements of infants through video alone and may assist clinicians in identifying possible motor development delays and disorders.
Keywords: Motor development; biomechanics; experimental design; kinematics; milestones.