Journal of NeuroEngineering and Rehabilitation

For this reason, we grouped subjects per level of ampu- tation (TFM and TFC together), and results are reported in Fig. 7a . The Kruskal-Wallis test now shows a stronger significance among groups ( p = 0.0186) and the pairwise analysis shows a statistically significant difference between TF and TT. The variability in P1S is much higher in am- putees than in Controls (Bartlett ’ s test for equal variances, p = 0.001). These results support a negative answer to Q6. Discussion In this study, we addressed three methodological and three clinical questions regarding the temporal and loading symmetry of transfemoral amputees (both mechanical and C-leg users) and transtibial amputees, to support in the development of more targeted rehabilitation goals, that are particularly needed [ 9 , 38 ] . As a general consideration, the self-selected walking speed was not statistically different among amputees, despite a slight increase in the median from TFM, to TFC, to TT toward Controls. Absolute values compare well with previously reported data [ 2 , 7 , 39 ] . For the sake of clarity, results are discussed below for each question, in comparison with the available literature whenever possible. Question Q1 Question Q1 asked if all amputees show the typical M-shaped pattern of the GRF, with presence and Fig. 3 a Impulse symmetry index (IMS) vs Stance symmetry index (SNS) and b First peak symmetry index (P1S) vs SNS. Each dot represents a subject. Subjects of the same group feature the same color (see legend in the plot). In ( a ), the purple parabolic line is the regression line for ALL subjects together. The equation of the fitting is reported on the right, with the fitting quality parameters R 2 (coefficient of determination) and RMSE (Root Mean Squared Error). No valid regression was found for P1S vs SNS. TFM: transfemoral mechanical knee users, TFC: transfemoral C-leg users, TT: transtibial amputees Cutti et al. Journal of NeuroEngineering and Rehabilitation 2018, 15 (Suppl 1):61 Page 34 of 72