Thorpe1 makes an interesting point regarding the conventional way of plotting the dependent variable on the y-axis and the independent variable on the x-axis for scatterplots of regression models. It should be noted that Figure 2 and the regression equations reported with it in our article2 are correct. However, the data are not graphed in the conventional way. Below is a revised version of Figure 2 graphed in the conventional format with isometric peak torque on the y-axis and muscle thickness on the x-axis alongside the original Figure 2.
Linear regression of isometric knee extensor peak torque and rectus femoris (RF) muscle thickness (A) and vastus lateralis (VL) muscle thickness (B) in both participants with cerebral palsy (CP) (gold squares) and participants with typical development (blue squares). All relationships were statistically significant, except for the relationship between RF muscle thickness and knee extensor torque in the CP group. In the regression equations, ISOM=isometric knee extensor peak torque (N·m), RFMT=RF muscle thickness (millimeters), and VLMT=VL muscle thickness (millimeters).
- © 2011 American Physical Therapy Association
