Segment angle. In both the male jump and female jump the foot angle changed relatively little during the preparatory phase, while the foot was flat on the floor. Then the foot angle increased and the segment rotated clockwise as the push-off phase began and continued to do so until the end of the movement.
For the female jump, the minimum foot angle occurred at the beginning of the movement when the foot was flat on the floor (-54 degrees). The maximum foot angle was -7 degrees which corresponded to the maximum plantarflexion of the foot. The range of motion was 47 degrees.
For the male jump, the minimum foot angle (-57 degrees) also occurred at the beginning of the movement. The maximum foot angle (-19 degrees) occurred at maximum plantarflexion of the foot. The range of motion for the male (38 degrees) was less than for the female.
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Figure 3. Foot angle during female jump (left) and male jump (right). The angle was calculated with respect to the vertical. Anatomical position is -54 degrees, since the subject started in this position, and motion occurred in a clockwise direction. | |
Segment velocity. Maximum angular velocity occurred just before take-off during both jumps. The maximum angular velocity was 133 degrees/second for the female jump, and for the male jump it was 242 degrees/second.
The trend is seen more easily in the male jump where there was little change in velocity throughout the preparatory phase. At the beginning of the push-off phase there is a dramatic increase in the velocity of the foot. After the maximum velocity was attained the segment velocity decreased until the end of the movement was reached.
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Figure 4. Foot angular velocity in the female jump (left) and male jump (right). Positive values represent clockwise rotation of the foot with respect to the vertical. | |
Joint angle1.In the female jump, the maximum angle of dorsiflexion was 292 degrees. Maximum dorsiflexion occurred at the end of the preparatory phase, just before the push-off phase. Maximum ankle plantarflexion (185 degrees) occurred during the push-off phase once the subject had left the ground. Range of motion of the ankle joint was 107 degrees.
The maximum ankle dorsiflexion was less in the male jump (282 degrees),than in the female jump. Maximum plantarflexion (211 degrees), which was substantially higher than the minimum angle in the female jump. The smaller maximum and the larger minimum angle led to a much smaller range of motion of the ankle joint in the male jump than in the female jump (71 degrees).
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Figure 5. Ankle angles in female jump (left) and male jump (right). Joint angle was calculated clockwise from shank to foot. Anatomical position corresponded to a measurement of 90 degrees. Angles larger than 90 degrees represented plantarflexion of the ankle. | |
Joint angle 2. In the female jump the maximum knee flexion (82 degrees) occurred at the end of the preparatory phase. The maximum knee angle attained was 180 degrees, which is full extension of the knee joint. The range of motion for this movement was 98 degrees.
The range of motion for the male jump (92 degrees) was slightly less than that of the female jump. The maximum flexion and extension knee angles for the male jump were 179 and 87, degrees respectively. The maximum knee angle for both subjects (at full knee extension) occurred at the height of the jump.
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Figure 6. Knee angles in female jump (left) and male jump (right). Knee angle is calculated counterclockwise from the thigh segment. Anatomical position corresponds to a measurement of 180 degrees. Angles smaller than 180 degrees correspond to knee flexion. | |
Angle-Angle Plot. At the start of the movement, the knee flexed (angle decreased), while the ankle angle remained fairly constant. Towards the end of the preparatory phase, the ankle began to dorsiflex (angle increased) while the knee continued to flex. The transition between the preparatory and push-off phases occurred when both joints reached maximum flexion. At this point, the knee angle began to extend (angle increased) and the ankle plantarflexed (angle decreased). Knee extension and ankle flexion continued throughout the push-off phase to the maximum height of the jump.
The primary difference between the two jumps occurred during the preparatory phase. In both the female and male jumps, the slope of the line was steepest during the descending portion of the movement, due to knee flexion. At the end of the preparatory phase, the joint coordination differed due to the greater plantarflexion in the female jump, which produced a shallower slope.
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Figure 7. Coordination of ankle and knee joint angles in female jump (left) and male jump (right). Arrows indicate initial direction of movement. The tail of the arrow indicates start position. Knee angle and ankle angle decrease during downward movement. Knee angle and ankle angle both increase during upward movement. | |
