Fig. 3

First swing angle (FSA) between days and systems. The box plot charts show the FSA values obtained using the optical tracking system (OTS) and the IMU-based system (IMU) in controls (A) and SCI (B) participants. The abscissa shows the system tested (OTS, IMU) on Day 1 and Day 2 (A, controls: Day 1 = orange, Day 2 = gray; B, SCI: Day 1 = light gray, Day 2 = light blue) and the ordinate shows the FSA values in degrees. C. The box plot chart shows the difference in absolute FSA values (refereed as ‘absolute error’) obtained using both systems in both groups. The abscissa shows the group tested (controls, SCI) and the ordinate shows the absolute error in degrees. In all graphs, the top and bottom lines of the box indicate the 75th percentile (top quartile) and 25th percentile (bottom quartile), respectively. The red lines in the middle of the boxes indicate the 50th percentile (median). The two bars extend from the maximum and minimum values. Range. ***p < 0.001