Biomedical Engineering Reference
In-Depth Information
3
From Measurement to Interpretation
The theoretical concepts required to calculate joint
kinematics, from the marker trajectories, will be presented
in this chapter. After presenting the different descriptions
possible for the attitude of body segments (position and
orientation in three-dimensional (3D) space), the
recommendations proposed by the International Society of
Biomechanics (ISB) for the main human joints to make the
description of joint angles more uniform, and the alternative
solutions proposed for certain specific joints will
be discussed. The definition of joint translations, which is
often overlooked, will also be described here.
3.1. The different parameters
There are many ways to set parameters for a system.
Here we will only discuss those used to analyze human
motion. In this context, where we focus on the motion of
joint, the human body is often considered as a mechanical
system composed of rigid bodies - dimensionally stable body
segments - joined to one another. We will therefore model
the human body, that is to say, propose simple hypotheses
for an easier analysis of motion according to the desired
results. Thus, depending on the intended application, we can
