Biomechanical Engineering Research Summer '97 or What I Did Over My Summer Vacation

This summer we looked at step strategies in recovering balance during a forward fall. We ran an experiment at The University of Michigan where we leaned our subjects (old and young males and females) forward at varying angles and released them to simulate the start of a forward fall. They were asked to recover their balance a couple different ways. During the Choice Step part of our testing the subjects were allowed to recover their balance using as many steps as they saw necessary. In the Single Step phase of the experiment the subjects were limited to using only one step to regain their balance. For the Voluntary Step portion of the experiment, the subjects were leaned forward at a small angle and when released were asked to step on a line, positioned on the ground, one third of their height away from them, as quickly as possible. We were looking for reaction times here. After the stepping component of the experiment was over it was on to strength testing. There were three strength stations in the lab we used: ankle strength, knee strength and hip strength.

Some interesting things we found are: the maximum angle from which the elderly are able to recover balance is smaller than young, when single or multiple steps are allowed. The maximum angle from which females are able to recover balance is smaller than males, when single or multiple steps are allowed. When given a choice, most elderly take multiple steps to recover from a fall; young often only take one step. Subjects that were successful in the Single Step portion were also successful in the Choice Step part of the experiment. Young can generate their maximum torque about their ankle, knee and hip faster than elderly which may contribute to the fact that young can recover from greater angles than elderly.