Basis of motion analyses

Biomechanics examines physical laws as well as their physiological events. Within the realm of physics motion analysis apply mechanics (power on physical objects) which can be dividing into two parts, that is, kinematics and dynamics. For calculations basic quantity of SI system is used, such as length (symbol: l, its basic quantity is m), mass (symbol: m, its basic quantity is kg), and time (symbol: t its basic quantity is s). SI defines the so called additional amounts in which plane angle (symbol: a, its basic quantity is rad) is crucial in biomechanics analysis. For the description of a motion it is necessary to apply a reference system which is correlated to place and position. Space/place can be characterized by three dimensions and its “idealized” form is the rectangular coordinate system whose starting point is origo. Motions of bodies can be studied and examined by using the points characterizing them in space. A point characterizing a body/object is its centre of gravity and its movement/motion, velocity and acceleration can be analysed (Barton, 1983).