Segment angle. Motion Analyze was used to calculate the shank angle over the complete duration of one gait cycle. The shank rotated counterclockwise for most of the gait cycle. Clockwise rotation of the shank occurred during the swing phase from toe off to heel strike. Counterclockwise rotation occurred from heel strike to mid-stance. The range of motion for our control subject was 80 degrees, while the range of motion for our subject with MS was 60 degrees. Maximum angle for both subjects was 20 degrees. The minimum angle of our control subject was -60 degrees, and the minimum angle for the subject with MS was -40 degrees.
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Figure 3. Shank angle in the normal walk (left) and the MS walk (right). Shank ankle is determined from the angle between the shank segment and the vertical axis. Anatomical position corresponds to an angle of 0 degrees, full extension. A positive slope of the curve represents clockwise rotations of the shank while a negative slope represents counterclockwise shank rotation. | |
Segment velocity. Shank velocities were similar for able-bodied and MS subjects. The maximum angular velocity occurred during the swing phase for both subjects. The maximum angular velocity of the shank for the control subject was 180 degrees/sec, while the maximum angular velocity for the subject with MS was 200 degrees/sec. The maximum velocity for the control subject occurred at 1 second. The maximum velocity for the subject with MS occurred at 1.2 second. The minimum angular velocity of the shank for the control subject was -100 degrees/sec and the minimum angular velocity of the shank for the MS subject was -110 degrees/ sec.
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Figure 4. Shank angular velocity in the normal walk (left) and the MS walk (right). Positive velocity represents clockwise rotation of the shank. | |
Joint angle1. The maximum knee joint angle for the control subject was 250 degrees, and the maximum angle for the subject with MS was 225 degrees. The maximum knee joint angle occurs during the swing phase of the gait cycle as the knee is the most flexed. The minimum knee joint angle for both subjects was 180 degrees. This minimum angle occurs during heel strike as the knee is most extended. The range of motion at the knee for the normal subject was 70 degrees and the range of motion at the knee for the subject with MS was 45 degrees.
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Figure 5. Knee joint angles in the normal walk (left) and the MS walk (right). Knee joint angle is calculated as the obtuse angle between the thigh segment and the shank segment. 180 degrees corresponds to anatomical position. Knee flexion occurs when the knee angle is greater than 180 degrees. | |
Joint angle 2. The maximum ankle joint angle for the control subject was 160 degrees, while the maximum angle for the subject with MS 170 degrees. The maximum ankle angle occurs with maximum dorsiflexion, which occurs during heel strike of the gait cycle. The minimum ankle angle for the control subject was 125 degrees, and the minimum angle for the MS subject was 110 degrees. The minimum ankle angle corresponds to maximum plantar flexion, which occurs during toe off of the gait cycle. The able-bodied subject had a range of motion about the ankle joint of 35 degrees. The subject with MS had a range of motion of 60 degrees. The minimum angle occurred at 0.80 sec for the control subject, and the minimum angle for the MS subject occurred at 0.50 sec.
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Figure 6. Ankle joint angles in the normal walk (left) and the MS walk (right). Ankle joint is calculated counterclockwise from the shank segment. Anatomical position for the ankle joint is 90 degrees. | |
Angle-Angle Plot. The graph of knee angle versus thigh angle represents the combined actions of the knee flexion-extension and thigh forward-backward rotation. The coordination of the thigh and knee was similar for able-bodied and MS subjects. After toe off, the thigh rotates forward about the hip joint and the knee flexes to its minimum angle. After the minimum angle, the knee extends until just before foot strike while the thigh rotates forward. During stance the thigh rotates backwards, and the knee flexes then extends.
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Figure 7. Coordination of the knee joint angle and the thigh segment angle in the normal walk (left) and the MS walk (right). Arrow points towards the direction of walk. The curve is followed in a counterclockwise direction. | |
