Data analysis and processing
SECONDARY
We completed initial kinematic and kinetic data processing in Visual 3D (C-Motion Inc., Germantown, MD). Data was filtered in Visual 3D using a fourth-order low-pass Butterworth filter with a 6 Hz cutoff frequency. We exported ground reaction forces (GRF) and heel marker locations to MATLAB. Using a custom script, we used GRF data to detect the left and right heel contact and toe-off times of each trial. We subtracted the initial heel contact time from the next heel contact time on the same side for both the left and right sides to calculate stride time. Our primary outcome was step length symmetry index, and our secondary outcomes were stance time and swing time symmetry. We calculated step length as the anterior-posterior distance between the leading leg heel marker and the trailing leg heel marker at heel contact of the leading leg in accordance with previous studies [where F stands for the leg on the fast belt or the leg that was not resisted by the exosuit, and S stands for the leg on the slow belt or leg that was resisted by the exosuit brace. Values of zero represent complete symmetry. Larger negative or positive values represent asymmetries between legs.