Figure 2. Body motion in walking (left ) and trotting (right). The stick figures represent the thigh, calf, and paw segments from top to bottom. The arrows describe the direction of the motion.
Both movements begin with the stance phase and progress through the swing phase. The phases were determined by analyzing the angular data of the thigh segment. For example the smallest angle corresponded to toe off. The walking movement took 0.92 seconds to complete a full cycle, while the trotting movement took 0.40 seconds for its cycle. The stance phase, which occurs at heel strike, is an extension of the hip into flexion of the knee and ankle (when the joints yield under the subject's body), through to extension and forward motion. The swing phase begins with flexion of hip, knee and ankle, as the paw pushes off the ground. The swing phase begins with toe off at 0.53 seconds for the walking movement and 0.20 seconds for trotting movement. From there the movement proceeds into extension of the ankle and knee and the foot is lifted from the ground. The movement continues into the stance phase of the next step cycle.
The cat's gait can be analyzed according to the percentage of time he's in single and double stance. During the walking movement, the cat is initially in a double stance for 3% of the total time. The cat is then in single stance for 40% of the total time. Before the cat enters the swing phase, the cat is in double stance for 14% of the total time. The cat is in swing phase for 40% of the cycle. Finally the cat is again in double stance as the swing phase ends for 3% of the total time. During the trotting movement, there was a very short period of double stance of the hind leg. For the trotting movement, the cat is initially in single stance for 33% of the total cycle time. Before entering the swing phase, the cat is in double stance for 8.5% of the total cycle. During the swing phase, the cat is in single stance for 50% of the total time. Finally the cat is again in double stance as the swing phase ends for 8.5% of the total time.
Both walking and trotting movements begin with the stance phase and proceed through the swing phase and ends as the leg is moving to the stance phase of the next cycle. The stance cycle begins in both movements with the thigh segment extending and the calf segment yielding under the load. This causes a flexion at the knee. The cat then lifts its paw and begins the swing phase. This involves a circular pattern of the entire leg with flexion of the thigh and calf segments. The swing phase concludes as the thigh, calf, and paw segments extend toward the ground.
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Figure 2. Body motion in walking (left ) and trotting (right). The stick figures represent the thigh, calf, and paw segments from top to bottom. The arrows describe the direction of the motion. | |