Joint Position. The maximum horizontal displacement of the ankle in the Tae Kwon Do kick was 1.04 meters and in the dance kick it was 1.02 meters. The maximum vertical displacement of the ankle for the Tae Kwon Do kick was 1.06 meters and for the dance kick it was .89 meters. The two kicks were very similar in horizontal displacement, but the front kick had a larger vertical displacement than the dance kick. The overall displacement for both kicks were similar. The combined displacement for the Tae Kwon Do kick was 1.2285 meters and for the dance kick it was 1.173 meters.
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Figure 8. Position of the ankle joint in the Tae Kwon Do front kick (left) and the straight leg dance kick (right). Forward motion corresponds to increasing values for horizontal position and upward motion corresponds to increasing values for vertical position. The small dashes represent the vertical position, the medium dashes represent the horizontal position, and the solid line represents the combined positions. | |
Joint velocity. The ankle joint linear velocity was greater in the dance kick than in the Tae Kwon Do kick. The maximum vertical velocity for the Tae Kwon Do kick was 3.5 m/s and the minimum vertical velocity was -3.17 m/s, compared to a maximum of 4.83 m/s and a minimum of -3.5 m/s for the dance kick. The maximum horizontal velocity of the Tae Kwon Do kick was 3.17 m/s and the minimum horizontal velocity was -3.17 m/s, compared to a maximum of 4.83 m/s and minimum of -1.67 m/s for the dance kick. These together combined to give a maximum velocity of 4.5 m/s and a minimum velocity of 0 m/s for the Tae Kwon Do kick. The dance kick had a combined maximum velocity of 5.46 m/s and a combined minimum velocity of 0 m/s. The dance kick was performed at a normal speed. Since we were limited to video capture at 30fps, the Tae Kwon Do kick was performed at a slower velocity than usual. If it had been performed at a normal speed, the combined velocity would have been much greater.
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Figure 9. Velocity of the ankle joint in the Tae Kwon Do front kick (left) and the straight leg dance kick (right). Forward motion corresponds to positive values for horizontal velocity and the upward motion corresponds to the positive values for vertical velocity. The small dashes represent the vertical velocity, the medium dashes represent the horizontal velocity, and the solid line represents the combined velocity. | |
Center of mass. The center of mass (CM) was calculated when the hip was flexed and the knee and ankle were both fully extended (Enoka 44). The CM location was similar for both motions. In the Tae Kwon Do kick the CM was slightly below the knee and outside of the body. In the dance kick the CM was immediately proximal to the knee and inside the body.
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Figure 10. Location of the center of mass (CM) in the Tae Kwon Do front kick (left) and the straight leg dance kick (right). Body segments are the thigh, lower leg, and foot. | |
