The centre of gravity of the human body in dynamic condition
The research carried out has shown that the greatest influence on position of the ellipse describing the position of the center of gravity of the human body has the inclination angle of the wheelchair. By controlling the change in the inclination angle value in the range from 0 ° to 5.4 °, standard deviation of the length of the horizontal half-axis of the ellipse (SD a) equal to 31.2 mm was obtained. For comparison, in case of changing the frequency of pushes (40 to 50 pushes per minute) of the wheelchair at a constant inclination angle, the standard deviation of the horizontal half-axis length (SD a) equal to 8 mm was recorded. The results of the study show a change in the position of the center of gravity of the human body in dynamic conditions. They are relative to the contact points of the wheelchair wheels with the ground. Using the dimensions of the plotted ellipses one can determine the values of pressure that affect the wheelchair's individual wheels.