Figure 3. Thigh angle in the two-legged jump (left) and the one-legged jump (right). Thigh angle is calculated from the vertical (0 deg corresponds to anatomical position), where positive values represent clockwise rotation.
Segment angle. The thigh angle, calculated from the vertical with clockwise being positive, was examined during both the two-legged jump and the one-legged jump. The maximum thigh angle (48.4 and 42.9 deg for the two-legged and one-legged jump, respectively) for both movements occurred at the start of the propulsion phase. This represented the point of greatest knee flexion. The minimum thigh angle (the point at which greatest knee extension occurred) was -2.8 deg for the two-legged jump and 10.4 deg for the one-legged jump. The range of motion, beginning at greatest knee flexion, was greater for the two-legged jump (51.2 deg) as compared to the one-legged jump (32.4 deg). In figure 3, decreasing angles corresponded to knee extension during the propulsion and ascending phase. The increasing angles corresponded to knee flexion during the descending and recovery phase.
|
|
|
|
Figure 3. Thigh angle in the two-legged jump (left) and the one-legged jump (right). Thigh angle is calculated from the vertical (0 deg corresponds to anatomical position), where positive values represent clockwise rotation. | |
Joint angle 1. The hip joint angle (the angle between the trunk and thigh segment) varied between the two-legged jump and the one-legged jump. The minimum hip angle for the two-legged jump, 103.7 deg, occurred at the beginning of the propulsion phase; the minimum hip angle for the one-legged jump, 128.8 deg, occurred halfway through the propulsion phase. The peak of the graph corresponded to the maximum hip angle, which occurred earlier for the two-legged jump than the one-legged jump. The maximum hip angles were 182.8 and 177.9 deg for the two-legged and one-legged jump, respectively. The range of motion was greater for the two-legged jump (79.1 deg) than the one-legged jump (49.1 deg).
|
|
|
|
Figure 4. Hip joint angles in the two-legged jump (left) and the one-legged jump (right). Hip angle is calculated counter-clockwise from the trunk segment. Anatomical position corresponds to 180 deg, while angles greater than 180 deg corresponds to hyperextension of the hip. Increasing angles represent hip extension and decreasing angles represent hip flexion. | |
Joint angle 2. The knee joint angle (the angle between the thigh and shank segment) varied slightly between the two jumping movements. The peak angles, which represented maximum knee flexion, occurred for both movements during the ascending phase; the maximum angle for the two-legged and one-legged jump was 188.5 and 183.7 deg, respectively. The minimum knee angle occurred at the beginning of the propulsion phase for the two-legged jump (109.3 deg), while the minimum angle for the one-legged jump (120.2 deg) occurred at the end of the recovery phase. The two-legged jump had a greater range of motion (79.2 deg) than the one-legged jump (63.5 deg).
|
|
|
|
Figure 5. Knee joint angles in the two-legged jump (left) and the one-legged jump (right). Knee angle is calculated counter-clockwise from the leg segment. Anatomical position corresponds to 180 deg, while angles greater than 180 deg corresponds to hyperextension of the knee. Increasing angles represent knee extension and decreasing angles represent knee flexion. | |
Joint velocity. The hip joint angular velocity was analyzed during the jumping movements. Positive angular velocity corresponded to hip extension while negative corresponded to hip flexion. The maximum angular velocity of the hip occurred during the propulsion phase in both jumping movements, while the minimum angular velocity of the hip occurred during the recovery phase. A noticeable discrepancy was observed between the two-legged hip angular velocity (511 deg/s) and the one-legged hip angular velocity (346 deg/s), with a difference of 165. The gap between the minimum hip angular velocities was only 79 deg/s, with the two-legged jump having -219 and the one-legged jump having -298 deg/s.
|
|
|
|
Figure 6. Hip joint angular velocity in the two-legged jump (left) and the one-legged jump (right). Positive hip joint angular velocity represents extension of the hip. Negative hip joint angular velocity represents flexion of the hip. | |
Angle-Angle Plot. The graphs below illustrates the correlation between the hip and knee movements in both jumps. Ascending angles corresponded to extension while descending angles corresponded to flexion. A direct relationship between the hip and knee joint was more apparent in the two-legged jump than the one-legged jump. In the two-legged jump, both joints extended and flexed almost concurrently, with a slight deviation in the latter half of the movement. However, in the latter half of the one-legged jump, the relationship was not as clear. During the initial stages of knee flexion the hip continued to extend. Midway through knee flexion, the hip reached peak extension and then began to flex with the knee, resulting in a relationship similar to the two-legged jump.
|
|
|
|
Figure 7. Coordination of the hip and knee angles in the two-legged jump (left) and the one-legged jump (right). The arrows on each of the graphs indicate the direction of movement. The origin of the arrows signifies the start of each jump that was analyzed. | |
