Determination of body segment masses and centers of mass using a force plate method in individuals of different morphology.

Body segment masses and center of mass (COM) locations are required to calculate intersegmental forces and net joint moments using inverse or forward dynamics equations. These inertial properties are estimated from methods involving cadavers or living individuals. The present clinical methods are limited to similar populations from which the anthropometric measures were obtained. This study presented a simple force plate method that can be used to determine subject-specific segment masses and COM locations and compared it to other well-known methods. The proposed method was tested in individuals with different body mass index (i.e., lean, normal, and obese) to verify its sensitivity. All the segmental mass and COM values obtained from the force plate method were within the range of those of the other methods for the entire sample. Significant differences were identified between the morphological groups in relative segmental masses at the upper arm and leg and foot, and COM locations at the leg and foot and head and trunk as obtained from the force plate method (p<0.05). The proposed method involves direct procedures to determine subject-specific segmental masses and COM locations. It is sensitive to detect differences between various morphological populations.