Segment angle. Although the thigh angles were similar in both the front-snap kick and front-limbering-up kick, the range of motion in the front-snap kick was greater than the range of motion in the second kick. The maximum trunk angle during the front-snap kick was 15 degrees, and the minimum was -130 degrees. In contrast, the maximum trunk angle during the front-limbering-up kick was 18 degrees, and the minimum was -141. The front-snap kick had a range of motion of 145 degrees, while the front-limbering-up kick had a smaller range of motion of 124 degrees.
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Figure 3. Upper leg angle during the front-snap kick (left) and the front-limbering-up kick (right). The thigh segment angle is calculated as the angular difference between the hip and the knee using a vertical line which passes through the hip joint. Anatomical position corresponds to approximately twenty degrees from the vertical. Counter-clockwise rotation corresponds to decreasing angle from the vertical and clockwise rotation corresponds to increasing angle from the vertical. | |
Joint angle 1. Hip motion during the front-snap kick was different than hip motion during the front-limbering up kick. During the front-snap kick, there was peak flexion of 296 degrees, occurred at 53% of the entire motion. The peak extension was 166 degrees, which occurred at the first frame of motion. The front-limbering up kick, on the other hand, had peak flexion of 309 degrees, at 44% of the motion, and peak extension of 162 degrees at 84% of motion. The hip joint in the front-snap kick had a range of motion of 130 degrees, compared to a larger range of motion of 147 degrees in the front-limbering-up kick.
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Figure 4. Hip angle during the front-snap kick(left) and the front-limbering-up kick (right). The hip angle is calculated using the posterior angle between the trunk and the thigh segments. Anatomical position represents and angle of approximately 180 degrees. Increasing angles, indicated by a counter clockwise rotation, represent flexion while decreasing angles represent extension. | |
Joint angle 2. Knee motion during the front-snap kick was different than knee motion during the front-limbering-up kick. They exhibited very different range of motions. During the front-snap kick, there was peak flexion of 171 degrees, which occurred at 44% of completion of the movement. The peak extension was 62 degrees, which occurred at 35% of motion. The front-limbering up kick, on the other hand, had a peak flexion of 166 degrees, at 4% of the motion, and a peak extension of 103 degrees at 22% of motion. The knee joint in the front-snap kick showed a range of motion of 109 degrees, while the joint in the front-limbering-up kick showed a smaller range of motion of 63 degrees.
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Figure 5. Knee angles in the front-snap kick (left) and the front-limbering up kick (right). The knee angle is calculated using the vertical axis to the knee. A clockwise directional measurement of the knee angle represents a decreasing angle, which in turn represents flexion of the knee. An increasing angle corresponds to extension of the knee. The anatomical position of the knee starts at approximately 170 degrees. | |
Joint velocity. The maximum angular velocity of the front-snap kick was similar to the velocity from the front-limbering up kick; however, the latter kick had a much "faster" minimum angular velocity. During the front-snap kick, there was a flexion angular velocity of 471 degrees/second, which occurred at 33% of motion. The extension angular velocity was -289 degrees/second, which occurred at 65% of motion. The front-limbering up kick, on the other hand, had a flexion angular velocity of 434 degrees/second, at 36% of the motion, and a extension angular velocity of -440 degrees/second at 60% of motion.
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Figure 6. Knee angular velocity in the front-snap kick (left) and front-limbering-up kick (right). Positive velocity represents flexion, while negative velocity represents extension for both figures. | |
Angle-Angle Plot. The coordination of the knee and hip joints in the front-snap kick was different than that of the front-limbering-up kick. During the front-snap kick the hip and knee angle were coupled out of phase, both changing at a constant ratio; this was determined from the negative diagonal slope of the line in the left graph. For a short period the knee angle remained relatively constant along the vertical axis of the graph, while the hip angle increased along the horizontal axis. At this point in the motion both angles reverse direction with a large delay between the two; they did not occur simultaneously. After their reversal the knee angle remains relatively constant on the vertical axis while the hip angle decreases along the horizontal axis. At the end of the motion the two joint angles are coupled and both changing at a constant ratio, seen as the negative diagonal slope. At the beginning of the front-limbering-up kick both the hip and knee angles are coupled out of phase with each other, seen as the negative diagonal slope. They then become coupled in phase, i.e. both angles are increasing, determined from the positive diagonal slope of the line. At the time of reversal there is a short delay indicating the simultaneous reversal in direction. Both angles then decrease with what appears to be a constant ratio, determined from the positive diagonal slope of the line. At the end of motion, with the hip angle still decreasing, the knee angle begins increasing, indicating an out of phase coupling, seen as the negative diagonal slope.
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Figure 7. Coordination of hip and knee angles in the front snap kick (left) and the front-limbering-up kick (right). Arrows indicate the initial direction of the movement. Both movements are read in a counter-clockwise direction. | |
