Bio Mechanical Analysis of Human Movement

Our research this summer involves investigating the biomechanics of resisting unintentional falls. The aim of this study is to investigate landing loads and lateral balance when stepping to arrest a fall. Which simply means the study of balance when trying to recover yourself when falling.

The overall goal of this research is to identify the causes of balance difficulties in elderly adults. Our study may be able to develop assistive devices, or fall prevention programs to decrease the possibility of falls. To do this, we have developed a biomechanical experiment that simulates a fall. The experiment is tested on both young and elderly subjects. The young subjects were tested at Hope College. Their results will be compared to the elderly subjects who will be tested at the University of Michigan.

The biomechanical experiment involves the use of forceplates and a motion analysis system in order to track the movement and forces generated at each relevant body segment. Photographs and data recordings obtained from subject tests are used to track the subjects center of mass and center of pressure of the feet, both of which are compared to the subject’s ability to regain their balance.

Figure 1 shows all the optotrack markers placed on each subject to track the location of body segments in 3D space. Figure 2 and 3 are pictures of one of the test subjects in the testing process. Figure 2 shows how the subject is leaned (30%) and Figure 3 shows the stepping (middle target) Which was anticipated when the subject was released.

The experiment was in two parts and the first part was where the subjects were given no instructions but simply asked to gain their balance by taking a step forward onto the forceplates. The second part was where the subjects were instructed to take a step forward onto specific targets marked on the force plates. There were three targets marked as the left, right and the middle.

After testing 20 subjects successfully the overall success rates were calculated. We observed that the lateral center of pressure decreases as time available decreases, success decreases as time available decreases and target failure thresholds were at 20% lean on the left targets and 30% lean on the right targets.

Figure 2 and Figure 3