What is the best way to collect maximum forward lumbar spine flexion values for normalizing posture to range of motion?

Spine angles are an important measure in biomechanics research and are commonly normalized to a percentage of range of motion. However, standardized methods to collect the reference posture trials for this normalization do not exist. The purpose of this study was to determine posture (seated or standing) and number of trials that should be collected and how to calculate the angle that best represents the maximum range. Forty healthy adults (22...