Mean profiles of the energy flow data in swing phase

Mean profiles of all subjects in terms of the energy flow data of the entire lower

extremity during the whole swing phase was shown in Figure 4-1, including the energy

flow profiles of the thigh in the four conditions as the young adults at the self-selected

walking speed (Figure 4-1a) and at the fast walking speed (Figure 4-2b) as well as the

doi:10.6342/NTU201901683

50

elderly at the self-selected walking speed (Figure 4-1c) and at the fast walking speed

(Figure 4-1d), the energy flow profiles of the shank (Figure 4-1e-1h), and those of the

foot (Figure 4-1i-1l). In general, the fluctuation trends of the eleven energy flow

elements along the swing phase were analogous in all the four conditions.

Nevertheless, it was noted that there were great energy fluctuation and great variations

among the subjects especially in the elderly at the fast walking speed.

As a representative pattern in the condition of the young adults at the self-selected

walking, the early stage of the swing phase showed a negative pelvis distal flow,

positive hip power, positive thigh proximal flow, and positive thigh energy change rate

(Figure 4-1a). In addition, there were negative thigh distal flow, insignificant knee

power, positive shank proximal flow, and positive shank energy change rate (Figure

4-1e). There were also negative shank distal flow and positive foot proximal flow

(Figure 4-1i). During the late stage of the swing phase, only the pelvis distal flow,

thigh distal flow, and shank distal flow were positive. The rest of the energy flow

elements were all negative. The magnitude of ankle power was especially close to

zero during the entire swing phase.

doi:10.6342/NTU201901683

Pelvis Distal Flow Hip Power Thigh Proximal Flow Thigh Energy Change Rate

W/kg

Swing phase (%) Young, Fast

Thigh Distal Flow Knee Power Shank Proximal Flow Shank Energy Change Rate

W/kg

Swing phase (%) Young, Fast

Shank Distal Flow Ankle Power Foot Proximal Flow

W/kg

Swing phase (%) Elder, Fast

Pelvis Distal Flow Hip Power Thigh Proximal Flow Thigh Energy Change Rate

W/kg

Swing phase (%) Elder, Fast

Thigh Distal Flow Knee Power Shank Proximal Flow Shank Energy Change Rate

W/kg

Shank Distal Flow Ankle Power Foot Proximal Flow

W/kg

Swing phase (%) Young, Self-selected

Pelvis Distal Flow Hip Power Thigh Proximal Flow Thigh Energy Change Rate

W/kg

Swing phase (%) Young, Self-selected

Thigh Distal Flow Knee Power Shank Proximal Flow Shank Energy Change Rate

W/kg

Swing phase (%) Young, Self-selected

Shank Distal Flow Ankle Power Foot Proximal Flow

W/kg

Swing phase (%) Elder, Self-selected

Pelvis Distal Flow Hip Power Thigh Proximal Flow Thigh Energy Change Rate

W/kg

Swing phase (%) Elder, Self-selected

Thigh Distal Flow Knee Power Shank Proximal Flow Shank Energy Change Rate

W/kg

Swing phase (%) Elder, Self-selected

Shank Distal Flow Ankle Power Foot Proximal Flow

doi:10.6342/NTU201901683

Pelvis Distal Flow Hip Power Thigh Proximal Flow Thigh Energy Change Rate

W/kg

Swing phase (%) Young, Fast

Thigh Distal Flow Knee Power Shank Proximal Flow Shank Energy Change Rate

W/kg

Swing phase (%) Young, Fast

Shank Distal Flow Ankle Power Foot Proximal Flow

W/kg

Swing phase (%) Elder, Fast

Pelvis Distal Flow Hip Power Thigh Proximal Flow Thigh Energy Change Rate

W/kg

Swing phase (%) Elder, Fast

Thigh Distal Flow Knee Power Shank Proximal Flow Shank Energy Change Rate

W/kg

Swing phase (%) Elder, Fast

Shank Distal Flow Ankle Power Foot Proximal Flow

W/kg

Swing phase (%) Young, Self-selected

Pelvis Distal Flow Hip Power Thigh Proximal Flow Thigh Energy Change Rate

W/kg

Swing phase (%) Young, Self-selected

Thigh Distal Flow Knee Power Shank Proximal Flow Shank Energy Change Rate

W/kg

Swing phase (%) Young, Self-selected

Shank Distal Flow Ankle Power Foot Proximal Flow

W/kg

Swing phase (%) Elder, Self-selected

Pelvis Distal Flow Hip Power Thigh Proximal Flow Thigh Energy Change Rate

W/kg

Swing phase (%) Elder, Self-selected

Thigh Distal Flow Knee Power Shank Proximal Flow Shank Energy Change Rate

W/kg

Swing phase (%) Elder, Self-selected

Shank Distal Flow Ankle Power Foot Proximal Flow

(a)

Pelvis Distal Flow Hip Power Thigh Proximal Flow Thigh Energy Change Rate

W/kg

Swing phase (%) Young, Fast

Thigh Distal Flow Knee Power Shank Proximal Flow Shank Energy Change Rate

W/kg

Swing phase (%) Young, Fast

Shank Distal Flow Ankle Power Foot Proximal Flow

W/kg

Swing phase (%) Elder, Fast

Pelvis Distal Flow Hip Power Thigh Proximal Flow Thigh Energy Change Rate

W/kg

Swing phase (%) Elder, Fast

Thigh Distal Flow Knee Power Shank Proximal Flow Shank Energy Change Rate

W/kg

Swing phase (%)

Shank Distal Flow Ankle Power Foot Proximal Flow

W/kg

Swing phase (%) Young, Self-selected

Pelvis Distal Flow Hip Power Thigh Proximal Flow Thigh Energy Change Rate

W/kg

Swing phase (%) Young, Self-selected

Thigh Distal Flow Knee Power Shank Proximal Flow Shank Energy Change Rate

W/kg

Swing phase (%) Young, Self-selected

Shank Distal Flow Ankle Power Foot Proximal Flow

W/kg

Swing phase (%) Elder, Self-selected

Pelvis Distal Flow Hip Power Thigh Proximal Flow Thigh Energy Change Rate

W/kg

Swing phase (%) Elder, Self-selected

Thigh Distal Flow Knee Power Shank Proximal Flow Shank Energy Change Rate

W/kg

Swing phase (%) Elder, Self-selected

Shank Distal Flow Ankle Power Foot Proximal Flow

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54

Figure 4-1 Mean energy flows throughout the whole swing phase in the young adults

and the elderly at the self-selected and fast walking speeds. Positive segmental

proximal/distal flow represents that the energy flows into the corresponding segment.

Positive joint power represents power generation.