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Message text written by "Parkinson's Information Exchange" >< Dear Dennis, On the subject of falling let me resubmit a posting I made last May becau= se I feel it is relevant to the issues you raise: On the subject of falling. In Parkinsonian terms I would define "falling" as festination which does not catch up to a displaced center of gravity. While ambulating anyone's= center of gravity is displaced forward. What prevents us from falling despite this forward imbalance is the continual advancement of our feet each step serving to catch us and prevent the imbalance from accelerating= making us fall. If we allow the imbalance to increase then we have to advance our feet more rapidly and this is running. If we can't advance o= ur feet a far enough distance then the cadence of our steps increases as we attempt to catch up to the imbalance. When the strides get too short we can't decelerate fast enough to catch up and neutralize this accelerating= force of displaced center of gravity and then the result is a fall. Falling almost always occurs while "on" because while "off" gait initiati= on problems prevent one from walking with any volitional displacement of center of gravity. The environment can, however induce displacement for example steep inclines or if someone gives the subject a shove (push/pull= test). So the problem becomes one of understanding how we can produce stride length steps of sufficient length to meet the demands of the environment.= This is where I would argue that vision plays a major role. What you see= or don't see can have a major impact on one's ability to generate necessa= ry stride length. Try walking with your eyes closed and you will not fall o= r festinate (have a spotter on your arm to be safe). Or try walking with arms extended straight out and hands hyperextended so you can see your fingernails - look at them as you walk to avoid falling. I am currently working on higher tech solutions. A couple of addenda: Normal walking requires projecting one's center of gravity beyond the fal= l point. The assurance that we can extend our leg adequately and quickly enough to catch ourselves before falling is what allows us to place ourselves in jeapordy of falling. Short stride length gait is compensato= ry walking i.e. it represents the longest stride we can take without projecting our body's center of gravity beyond the fall point. When the= stride shortens to the point where there is inadequate time or space to walk with a normal gait pattern (heel off, toe off, swing phase) then we "save time" by shuffling. = Finally, I would disagree with your recommendation to swing your arms. In= fact I would advise just the opposite - keep your arms still by putting them behind your back or holding a cane. This has to do with how we perceive apparent motion of the environment relative to our own motion. = regards, Tom