# Relation between Step-To-Step Transition Strategies and Walking Pattern in Older Adults
## 3 Results
### Joint and Elevation Angles  
At the level of the hip, there is a modification of the maximum hip extension (\(F_{2,86}=5.6\); \(p=0.005\)): the hip extension is similar among Young and Older\({}_{\text{A}}\) groups (\(p=0.149\)) but smaller in Older\({}_{\text{NA}}\) (\(p=0.002\); Figure 2A). In all groups, no effect of speed is observed (\(F_{1,86}=0.1\); \(p=0.765\)). At the level of the knee, at FC, no significant effect of group is noticed. At the level of the ankle, a modification of the maximum ankle plantar-flexion is observed(\(F_{2,86}=24.1\); \(p<0.001\)): the maximal plantar-flexion is smaller in OlderA compared to Young (\(p<0.001\)), and in OlderNA compared to OlderA (\(p<0.001\)). In each group (interaction: \(F_{2,86}=0.6\); \(p=0.527\)), the ankle plantar-flexion increases with speed (\(F_{1,86}=6.6\); \(p=0.012\)).  
When looking at the elevation angles, the mean trunk inclination differs between groups: at \(1.11\) m s\({}^{-1}\), the inclination is \(-3.1\pm 1.7\)\(\circ\), \(-8.0\pm 4.3\)\(\circ\) and \(-9.5\pm 4.9\)\(\circ\) in Young, OlderA and OlderNA, respectively. The inclination is greater in OlderNA compared to OlderA (\(p=0.045\)), and in OlderNA compared to Young (\(p<0.001\)). Moreover, the shank and foot ROM are different between groups (shank: \(F_{1,86}=3.4\); \(p=0.037\); foot: \(F_{1,86}=6.6\); \(p=0.032\)): the ratio between thigh and shank ROM is smaller in Young than in OlderNA (\(p=0.001\)) but similar compared to OlderA (\(p=0.065\)), whereas the ratio between shank and foot ROM is different among Young and older adults (\(F_{1,86}=10.8\); \(p=0.001\)) but not among OlderA and OlderNA (\(p=0.830\); Figure 3A). In addition, the phase shift between shank and foot segments is smaller (more in phase) in OlderNA than in OlderA (\(p=0.002\)) and in Young (\(p=0.012\); Figure 3A), whereas the phase shift between the thigh and shank segments is not different between groups (\(F_{2,86}=1.1\); \(p=0.320\)).  
Figure 2: Joint kinematics. (**A**) Ensemble-average traces of the hip, knee and ankle angle joint taken from the right side of the subjects during a stride for the three groups walking at 1.11 m-s\({}^{-1}\). All the curves of each subject were first averaged (mean curve). The curves presented here are the average of the mean curves of all the subjects (ensemble-average) and the dark grey areas are the standard deviations. Positive values correspond to flexion (dorsiflexion for the ankle) and negative values correspond to extension (plantar-flexion for the ankle). (**B**) Maximal hip extension (left), knee flexion at foot contact (middle) and maximal ankle plantar-flexion (right). The symbols \({}^{*}\) and \(V\) indicate a significant effect of age and speed, respectively. Other indications as in Figure 1.  
When speed increases, the range of motion (ROM) of the trunk, thigh and foot elevation angles increased (trunk: \(F_{1,86}\) = 4.1; \(p\) = 0.045; thigh: \(F_{1,86}\) = 5.2; \(p\) = 0.025; foot: \(F_{1,86}\) = 4.8; \(p\) < 0.032) in each group, whereas the ROM of the shank elevation angle and the trunk mean inclination were not affected (shank ROM: \(F_{1,86}\) = 1.2; \(p\) = 0.276; trunk mean: \(F_{1,86}\) = 3.9; \(p\) = 0.051).