Mass-inertial Parameters of the Human Thigh Based on Data for Bulgarian Males: Three-dimensional Mathematical Model Study

Abstract

The estimation of body segment parameters is important for humanmotion analysis and many biomechanical activities. For studying these aprecise modeling of the individual segments of the body is necessary. The aim of this work is to improve the geometric modeling of the human thigh of the Bulgarian males, taking into account that the segment is dissect from the torso with a plane passing through the anterior superior iliacspine at an angle of 37 degrees to the sagittal plane. In our previous studythe thigh was modeled as a frustum of cone. In the current study thethigh is modeled with geometric body being a combination of a frustumof circular cone on top of which is placed a part of cylinder cut with aplane making angle of 53 with respect to its base. This second part ex-tends from anthropometric points omphalion - iliospinale. Modeling of thebody segments by means of simple geometrical bodies enforces a seriousapproximation of their shape and, therefore, of their volume and relatedcharacteristics as mass and moments of inertia. Hence, adjustment of themeasured geometrical parameters that would produce the best approxima-tion of the body segment mass characteristics is highly desirable. This canbe done by using the regression mass equations derived in Zatsiorsky andSeluyanov and Shan and Bohn. Yet, by doing so we avoid deviations ofthe adjusted parameters from the measured values, larger than 10%. Wederive analytically and estimate numerically the volume, mass, the positionof the center of mass and moments of inertia of the thigh and compare theseresults with the ones available from the literature for other Caucasian.