## 3 Results
### Results from the Human Subjects Testing
#### 3.2.1 Ground Reaction Forces  
The ground reaction forces were directly measured during the human subjects testing through force plates on the treadmill. The mean values of the ground reaction forces vs. the gait cycle are shown in Figure 9. For each leg, the mean values and the standard deviations of the maximum values of the ground reaction force were calculated from 50 gait cycles. Those maximum values with their mean values and standard deviations are reported in the first section of Table 4 (\"Maximum Ground Reaction Forces\") as absolute values, and normalized with respect to the body weight of the participants in the second section of the same Table (\"Maximum Ground Reaction Forces/Body Weight/9.81 m/s2\").  
To compare the ground reaction force values measured from the healthy foot and the prosthetic foot, the procedure illustrated in Figure 10a was followed and the results are reported in the third section of Table 4 (\"Prosthetic Leg Ground Reaction Forces/Health Leg Ground Reaction Forces\"). To compare the measured ground reaction force values while the participants were using their prosthesis and using MyFlex-\(\delta\), the procedure illustrated in Figure 10b was followed, and the results are reported in the fourth section of Table 4 (\"Ground Reaction Forces Using MyFlex-\(\delta\)/Ground Reaction Forces Using their Own Prosthesis\").  
Figure 9: The ground reaction forces mean value calculated from 50 gait cycles of (**a**) Participant 1, (**b**) Participant 2 and (**c**) Participant 3: healthy leg, using their own prosthesis (dark red straight line); healthy leg, using MyFlex-\(\delta\) (dark green straight line); prosthetic leg, using their own prosthesis (light red dashed line); prosthetic leg, using MyFlex-\(\delta\) (light green dashed line).  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**Participant 1**} & \multicolumn{2}{c}{**Participant 2**} & \multicolumn{2}{c}{**Participant 3**} \\ \hline \multicolumn{6}{c}{Maximum Ground Reaction Forces} \\ \hline Leg and prosthesis used & mean & std & mean & std & mean & std \\ \hline Healthy leg, own prosthesis & 1088 N & 37 N & 809 N & 6 N & 820 N & 31 N \\ Healthy leg, MyLeg prosthesis & 1078 N & 27 N & 824 N & 14 N & 872 N & 30 N \\ Prosthetic leg, own prosthesis & 993 N & 18 N & 808 N & 9 N & 760 N & 50 N \\ Prosthetic leg, MyLeg prosthesis & 1014 N & 19 N & 814 N & 9 N & 751 N & 25 N \\ \hline \multicolumn{6}{c}{Maximum Ground Reaction Forces/Body Weight/9.81 m/s2} \\ \hline Leg and prosthesis used & mean & std & mean & std & mean & std \\ \hline Healthy leg, own prosthesis & 107\% & 4\% & 103\% & 1\% & 114\% & 4\% \\ Healthy leg, MyLeg prosthesis & 106\% & 3\% & 104\% & 2\% & 121\% & 4\% \\ Prosthetic leg, own prosthesis & 98\% & 2\% & 102\% & 1\% & 106\% & 7\% \\ Prosthetic leg, MyLeg prosthesis & 100\% & 2\% & 103\% & 1\% & 104\% & 3\% \\ \hline \multicolumn{6}{c}{Prosthetic Leg Ground Reaction Forces/Healthy Leg Ground Reaction Forces} \\ \hline Prosthesis used & mean & std & mean & std & mean & std \\ \hline Own prosthesis & 91.4\% & 3.7\% & 99.9\% & 1.4\% & 92.8\% & 7.2\% \\ MyFlex-\(\delta\) & 94.0\% & 3.0\% & 98.8\% & 1.6\% & 86.3\% & 4.5\% \\ \hline \multicolumn{6}{c}{Ground Reaction Forces Using MyFlex-\(\delta\)/Ground Reaction Forces Using their Own Prosthesis} \\ \hline Leg side & mean & std & mean & std & mean & std \\ \hline Healthy leg & 99.2\% & 3.9\% & 101.9\% & 1.8\% & 106.4\% & 4.7\% \\ Prosthetic leg & 102.1\% & 2.9\% & 100.7\% & 1.9\% & 99.1\% & 6.8\% \\ \hline \end{tabular}
\end{table}
Table 4: Maximum ground reaction forces. Mean values (mean) and standard deviations (std) are calculated from 50 gait cycles.  
Figure 10: Procedures for the calculation of: (**a**) the ratio between the ground reaction force measured from the prosthetic leg (GRF-PL) and the healthy leg (GRF-HL); (**b**) the ratio between the ground reaction force measured while using MyFlex-\(\delta\) (GRF-MF) and while using their own prosthesis (GRF-OP).