Methods
Ten healthy test subjects from the surrounding Weld County areas volunteered to participate in the trials and came to the biomechanics lab at the University of Northern Colorado. The average subject heights was 1.7+0.1 meters and the mass was 78.6+13.6 kilograms. In the biomechanics lab, a 10 meter long walkway was set up with a step that was 16 centimeters high in the middle. Each of the test subjects were asked to walk at two different paces up the curb while the data were recorded. The first pace, a self-selected comfortable pace, was chosen by each subject, and the second was the fastest walking pace that the subject could obtain safely without feeling uncomfortable or without running.
The materials used in this study were a VICON Motion Capture System, three force plates, a timing system, and a curb with one of the three force plates built in.
The VICON system consisted of tiny markers covered in reflective material that are located by ten different cameras placed around the room. The cameras are able to detect the bright reflection from the markers. There were 41 markers placed on a different part of the body. (List where each is placed). The VICON system collects data from the sensors at a rate of 100 Hertz and then uses that information to display an image of the subject on a computer screen. During the trials, the motion capture system took data from the moment the subjects started walking to the point where the person was completely clear of the step and the third force plate. The system also recorded the center of mass for the participant at any given time during the walking period. For this particular study, the center of mass data were evaluated from the first heel strike of a given foot on one of the force plates up till the toe of the last foot lifted off the third force plate.
Two force plates are located on the ground in front of the curb, and the third was built into the curb. These force plates measured and collected the ground reaction forces and the center of pressure of the participants at a rate of 2000 Hertz. For each trial, the subjects would walk across these force plates. An acceptable trial would consist of the subject stepping on each force plate with only one foot.
The timing system has sensors that are set over a 5 meter section of the walkway where the curb was located. The participant would walk past the first timer, triggering the start and then the second triggering the end of the timing.
After the trials were performed, the data were analyzed using VICON Nexus (1.8.5). The markers were reconstructed and labeled. This generated a virtual image of the test subject on the computer and displayed the vectors of the ground reaction forces on that person. The program created a timeline of the progression of the participant from the start to the end of each walk up the curb.
The data from the VICON system and the force plates was then exported to an Excel file. From here, each of the values in the data was processed and graphed.
The materials used in this study were a VICON Motion Capture System, three force plates, a timing system, and a curb with one of the three force plates built in.
The VICON system consisted of tiny markers covered in reflective material that are located by ten different cameras placed around the room. The cameras are able to detect the bright reflection from the markers. There were 41 markers placed on a different part of the body. (List where each is placed). The VICON system collects data from the sensors at a rate of 100 Hertz and then uses that information to display an image of the subject on a computer screen. During the trials, the motion capture system took data from the moment the subjects started walking to the point where the person was completely clear of the step and the third force plate. The system also recorded the center of mass for the participant at any given time during the walking period. For this particular study, the center of mass data were evaluated from the first heel strike of a given foot on one of the force plates up till the toe of the last foot lifted off the third force plate.
Two force plates are located on the ground in front of the curb, and the third was built into the curb. These force plates measured and collected the ground reaction forces and the center of pressure of the participants at a rate of 2000 Hertz. For each trial, the subjects would walk across these force plates. An acceptable trial would consist of the subject stepping on each force plate with only one foot.
The timing system has sensors that are set over a 5 meter section of the walkway where the curb was located. The participant would walk past the first timer, triggering the start and then the second triggering the end of the timing.
After the trials were performed, the data were analyzed using VICON Nexus (1.8.5). The markers were reconstructed and labeled. This generated a virtual image of the test subject on the computer and displayed the vectors of the ground reaction forces on that person. The program created a timeline of the progression of the participant from the start to the end of each walk up the curb.
The data from the VICON system and the force plates was then exported to an Excel file. From here, each of the values in the data was processed and graphed.