The purpose of this report is to determine if there are differences between two different gait types of a cat. In the qualitative analysis, the researchers noticed that there was a much deeper flexion in the ankle and knee during trotting. This was determined by comparing the stick figures for both movements. It is also notable that there is little deviation in the vertical direction of the hip joint during walking, while in trotting, the hip joint marker moves along a wave-like path. No other differences were noted.
In an analysis of angular kinematics, both movements were very similar. Thigh segment angle and velocity showed no radical differences outside of the fact that in trotting the velocity was larger. The knee angle analysis showed that in both movements, the angles were similar, but the time it took to progress through the angles was shorted for the trotting movement. The ankle angle analysis shows results similar to the knee analysis, with the angles being more extreme in the trotting. When contrasting the coordination between the thigh segment angle and the knee joint angle, both movements have minor differences, again. The overall shape is very similar with the trotting movement have larger angles.
The linear kinematics analysis showed some differences between the movements. The linear movement of the knee joint shows that, overall, the knee joint moved the same distance in both movements. However, in the horizontal direction, the knee moved slightly further in walking than in trotting. This can be seen in the data for the hip joint as well. The velocity of the knee joint shows the largest differences. In the trotting movement, the knee joint moved at a much larger velocity than in walking. This is also the major difference in the velocity of the hip joint.
In conclusion, there is no significant difference between walking and trotting when considering angular kinematics. When looking at linear kinematics, the most significant difference between the two gaits is the velocity of the limbs as they move through space and the angle size of the knee.
Throughout the duration of this study, we have encountered many problems. The first problem was the placement of joint markers. It was very difficult to determine the cats joints, and keep the markers in a consistent position. Also, there were inconsistencies in the determination of the centers of these joint markers when digitizing the video. This was due to blurring of the video (from the speed of the movement). There were also limitations due to the cat. It was a difficult task to get the cat to move in the proper area. It was even more difficult to get him to move consistently. There is also limitations due to the fact that only one trial was run. To get true results from this, several trials needed to be done to determine if the conclusions were true or merely one-time occurrences. Another way to get true results would be to analyze more than one cat's movements.
GE. Glasgow, Jr., R.M. Reinking, D.G. Stewart Sept. 1973 The Cat Step Cycle: hind Limb Joint Angles and Muscle Lengths during Unrestrained Locomotion. The Journal of Morphology, 141: 1-41.