TABLE II.

Video Analysis Study Designs

	Primary Aim	Advantages	Disadvantages
Qualitative	Describe and categorize NC-ACLI scenarios	Identify environmental risk factors and gross motor patterns	Provide limited insights into mechanisms of NC-ACLI
Quasi-quantitative	Estimate joint angles and bin findings into categories	Determine general trends in body position during NC-ACLI	Lack the precision to determine high-risk joint positions
Quantitative
2D	Directly measure joint angles and body positions during NC-ACLI	Ability to collect larger sample size due to public-domain videos and efficient analyses	Single plane fails to account for all 6 degrees of freedom; accuracy unassessed in validation studies; requires cardinal planes, which can be difficult to obtain
3D modeling	Directly measure joint angles and body positions during NC-ACLI	Any perpendicular camera views are adequate	Extensive time required for the analysis, criticized for low accuracy
Direct linear translation	Directly measure joint angles and body positions during NC-ACLI	Closest approximation to controlled laboratory settings	Difficulty obtaining sufficient numbers for comparative studies