COM-COP inclination angles

Keywords— Core stability ball exercise. Ball size. Posture balance, COM-COP inclination angles. Muscle activation. 

A repeated measured ANOVA were used to examine the relationships between muscle activation, COM parameters, COP parameters and COM-COP inclination angles of three ball sizes and two ground contact areas. Post hoc test were used LSD to evaluated. Two-sided significance was defined as p < 0.05. 

Figure 4 shows the COM-COP inclination angles. There were significant differences in COM-COP AP inclination angles (p=0.002) and ML inclination angles (p =0.006) among different ball sizes. 

In examining the COM and COP displacements, we found that the ML components are greater than AP components in agreement with the inclination angles. Also, in roll out exercise position the base of support in AP direction is greater than in ML direction because two hands and ball contact areas in the AP direction makes the AP inclination angle limited. In contrast, the base of support is smaller in the ML direction. 

---