# Biomechanical Task-Based Gait Analysis Suggests ReWalk Gait Resembles Crutch Gait
## 3 Results
As we move on to the LA gait stage, the patterns for all of the observed muscles (RF, BF, TA, and SL) seem to match pretty well for ReWalk and crutch gait, at least compared to natural gait. Collectively, other than RF during the SS gait stage, we do not observe any significant qualitative differences in time-trace patterns within the biomechanical phases. We also obtained the average EMG WL of all steps performed during each gait session in order to quantitatively evaluate our previous analysis (Figure 3b). Each gait condition was performed at different speeds and different weight-bearing conditions; thus, we would like to point out that careful interpretation is warranted. Specifically, the absence of activation, such as, missing activation of RF, and TA and the activation of SL in the WA phase, was observed and should be investigated further. However, because the difference observed with BF was not in EMG levels but rather a delay in timing, the mean EMG WL values alone do not exhibit as drastic changes. Thus, examination of EMG levels as well as time trace patterns seems necessary when evaluating EMG patterns. We also analyzed the hip, knee, and ankle joint angles during the gait sessions (Figure 4). Both ReWalk and crutch gait show similar hip angles, which display noticeably more flexion compared to natural gait throughout the entire gait cycle. However, this is not observed with the AFO gait (Figure S2). This is somewhat expected considering the subject leans forward at the hips when using crutches. The knee joint angles, on the other hand, are relatively comparable during the WA and SS phases for all gait conditions, while some discrepancies are apparent in the LA phase. The maximum knee flexion angles of the crutch and ReWalk gaits are similar; however, the point at which this angle occurs is delayed. This may be due to the ReWalk's \"pre-programmed\" slight pause before the start of the swing motion. Lastly, ReWalk and crutch gait both lack dorsiflexion during the early WA phase, just as the EMG pattern analysis suggested. Thus, taking the EMG and joint angle pattern analysis together, our results suggest that ReWalk and crutch gait are similar to each other and significantly different from natural gait, particularly during the WA phase. We have made several postulations regarding how crutches are mainly responsible for changes in gait patterns observed with ReWalk by examining EMG patterns and joint  
Figure 4: Comparison of joint angles in subject 1 divided according to the gait-related biomechanical phases. (**a**) Overlay of mean hip, knee, and ankle joint angles during WA, SS, and LA phases obtained from ReWalk (red lines), natural (blue lines), and crutch (grey lines) gait conditions. (**b**) Bar graph representing the average joint angles over the WA, SS, and LA phase periods. The data are shown as mean \(\pm\) SD. Statistical significance was assessed by independent two sample \(t\)-tests (* denotes \(p\) < 0.05). Figure 3: Comparison of EMG patterns in subject 1 divided according to the gait-related biomechanical phases. (**a**) Overlay of mean EMG WL during WA, SS, and LA phases obtained from ReWalk (red lines), natural (blue lines), and crutch (grey lines) gait conditions. (**b**) Bar graph representing the average EMG WL over the WA, SS, and LA phase periods. The data are shown as mean \(\pm\) SD. Statistical significance was assessed by the [PERSON] signed rank test (* denotes \(p\) < 0.05). angles acquired from one subject. To further substantiate our postulations, we investigate whether these observations are consistent throughout the participant group. Table 1 shows that the changes in subject #1's gait patterns when walking with ReWalk were also observed with most of the subjects that participated in this study. We note that both increased hip flexion during the SS phase and decreased knee flexion during the LA phase are observed throughout the group, which is not surprising considering that it is only natural when negotiating balance with partial body weight supported by crutches.