Segment angle. The thigh rotated clockwise during the flexion phase of the Stairmaster climbing and the stair climbing. During the extension movement, the thigh rotated counterclockwise. The maximum thigh angles were very similar during the Stairmaster climbing (51 deg) and stair climbing (50 deg). However, the minimum thigh angle was greater during the Stairmaster climbing (9 deg) than the stair climbing (-9 deg). Therefore, the range of motion during Stairmaster climbing (42 deg) was less than the stair climbing (59 deg).
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Figure 3. Thigh angle during Stairmaster climbing (left) and stair climbing (right). The vertical axis represented zero degrees and was the angle corresponding to anatomical position. Positive values represented clockwise rotation while negative values indicated hyperextension. | |
Segment velocity. The maximum angular velocity of the thigh in the flexion phase was less during Stairmaster climbing (110 deg) than the stair climbing (170 deg). However, the minimum angular velocity was similar for the Stairmaster climbing (-120 deg) and the stair climbing (-115 deg) in the extension phase.
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Figure 4. Thigh angular velocity in the Stairmaster (left) and the stair climbing (right). Positive angular velocity values represented clockwise rotation. | |
Joint angle1. The peak hip extension occurred at the beginning and the end of both motions when the foot was in contact with the ground and was less during Stairmaster climbing (160 deg) than during the stair climbing (180 deg). However, maximum flexion was similar for Stairmaster climbing (120 deg) and stair climbing (125 deg). Therefore, the hip range of motion for Stairmaster climbing (40 deg) was less than stair climbing (55 deg).
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Figure 5. Hip joint angles in Stairmaster climbing (left) and stair climbing (right). Anatomical position corresponded to 160 degrees for Stairmaster climbing and 180 degrees for stair climbing. Angles less than 160 degrees for Stairmaster climbing and 180 degrees for stair climbing indicated hip flexion. | |
Joint angle 2. The peak knee extension for the Stairmaster motion was 170 degrees and occurred at the beginning and end of the movement. The peak knee flexion during the Stairmaster motion was 85 degrees. The range of motion was 85 degrees for the Stairmaster motion. During the stair climbing movement, the maximum knee angle of 175 degrees occurred at the beginning and end positions of maximum extension. The minimum knee angle of 90 degrees occurred at the position of maximum flexion. The range of motion was also 85 degrees for the knee angle. The range of motion for the knee (85 degrees) was the same for both movements although the specific joint angles were slightly different for the two motions. In the stair climbing, the foot contacted the higher stair at the transition between peak flexion and peak extension.
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Figure 6. Knee joint angles in the Stairmaster (left) and the stair climbing (right). For the Stairmaster and stair climbing movement, the vertical axis represented 170 degrees and 175 degrees, respectively and was the angle corresponding to the anatomical position. Angles less than 170 degrees for Stairmaster climbing and 175 degrees for stair climbing indicated knee flexion. | |
Angle-Angle Plot.The hip and knee joint angles were similarly coordinated for both the Stairmaster and stair climbing motions, except at the transition between flexion and extension phases midway through the movements. The movement began with both joints fully extended. During the flexion phase, both joints flexed together. The joints reversed direction and then extended together. The hip and knee joint angles were tightly coupled during Stairmaster climbing. However, during the stair climbing motion, the knee began to extend while the hip was still flexing at the end of the flexion phase to compensate for the shift of the body weight from one limb to another while the body was moving forward.
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Figure 7. Coordination of hip and knee joint angles in the Stairmaster (left) and the stair climbing (right). The arrow indicated the direction of movement with the starting position at the tail of the arrow. | |
