Figure 3. Scatter plots for different pairs of maximal voluntary forces in different directions (i.e. planes of the intended motion). All for the sitting position of testing. In each case the counter-movements were averaged and taken as a representative of the MVC in a certain anatomical plane: sagittal (average of flexion and extension), frontal (average of left and right lateral flexion) and transversal (average of rotation to the left and to the right). Figures A, B and C depict the relationships between the planes of the intended trunk movements (i.e. the corresponding MVCs). Analysis includes both genders.