# Long-Term Effects of a Soft Robotic Suit on Gait Characteristics in Healthy Elderly Persons
## 4 Results  
Figure 6 compares average maximum hip, knee, and ankle angles of each week between the POFF condition and the PON condition. It is shown that the effects of assistance were mainly detected in hip flexion, knee flexion, and ankle dorsiflexion, with average increases of 10.5%, 1.9%, and 33.7%, respectively. In addition, the tendency of the values increased as the week progressed. Figures 7 and 8 compare the joint angles of hip, knee, and ankle achieved in the POFF condition between Week 1 and Week 6. It was observed that, after six weeks' use of the robotic suit, the gait characteristics were changed. Specifically, maximum hip flexion angle was reduced from 27.6 \(\pm\) 3.1 degrees to 22.5 \(\pm\) 3.2 degrees, while maximum hip extension angle was increased from 15.4 \(\pm\) 9.1 degrees to 20.8 \(\pm\) 5.2 degrees. For the knee joint, maximum extension angle reached 3.6 \(\pm\) 3.9 degrees from 10.1 \(\pm\) 9.0 degrees, while maximum flexion angle reduced to 58.3 \(\pm\) 6.2 degrees from 66.5 \(\pm\) 5.0 degrees. Besides that, in the case of ankle joint, the maximum dorsiflexion angle was reduced to 3.4 \(\pm\) 5.8 degrees from 7.4 \(\pm\) 5.0 degrees, while maximum plantar flexion angle was increased to 21.4 \(\pm\) 5.6 degrees from 19.4 \(\pm\) 6.1 degrees. Statistically-significant differences were found in maximum hip flexion, maximum knee flexion, and maximum ankle dorsiflexion, with an average reduction of 20.7%, 12.5%, and 54.3%, respectively, in Week 6. Figure 6: Comparison of average maximum joint angles of each week between the POFF condition and the PON condition. Here, flex. : flexion, ext. :extension, d.f. : dorsiflexion, and p.f. : plantar flexion. Figure 8: Comparison of maximum joint angles achieved in the POFF condition between Week 1 and Week 6. Here, flex. : flexion, ext.extension, d.f. : dorsiflexion, and p.f. : plantar flexion. On each bar chart, the error bar denotes one standard deviation. Figure 7: Comparison of joint angles achieved in the POFF condition between Week 1 and Week 6. On each graph, the solid curve represents the average value, and the shadowed region denotes one standard deviation. As a result of the above-mentioned changes, the walk ratio varied concurrently, as illustrated in Figure 9. It is shown that, for each week, the walk ratio of the PON condition was higher than that of the POFF condition. In addition, the tendencies of both conditions increased as the week progressed (POFF: \(y=0.00009148x+0.00503251\), \(R^{2}=0.623\); PON: \(y=0.00004885x+0.00555119\), \(R^{2}=0.397\)), but the difference between the two conditions decreased. Figure 10 shows statistical comparisons of the six weeks' average walk ratio between the POFF condition and the PON condition. It is shown that walk ratio of the PON condition was 0.0057 m/steps/min, while that of the POFF condition was 0.0054 m/steps/min. A statistically-significant difference was detected. Figure 11 compares the individual walk ratio of the POFF condition between Week 1 and Week 6. It is shown that, compared with initial state, the walk ratio of three subjects increased 6.8%, 22.2%, and 13.7%, respectively, after six weeks' use of the robotic suit, while that of one subject slightly decreased 2.9%. Figure 12 shows statistical comparisons of the walk ratio achieved in the POFF condition between Week 1 and Week 6. It is shown that, although no significant difference was detected, after six weeks, the walk ratio increased from \(0.0052\pm 0.0013\) m/steps/min to \(0.0057\pm 0.0009\) m/steps/min in the POFF condition, with an average increase of 9.8%. Figure 13 demonstrates typical motions around the timings of the toe off and the heel contact. One can observe that, compared with Week 1, the lower limb of Week 6 acted more like an inverted pendulum motion. Figure 10: Comparison of the average walk ratio between the POFF condition and the PON condition. On each bar chart, the error bar denotes one standard deviation.