The problem with bar stools for us men!

On a recent Sunday, I was at a local bar when a customer fell over backwards while seated on a standard bar stool. Unfortunately, he his his head and was subsequently transported to an emergency care center. This was the second time I'd witnessed such an event over the years. In both cases the accident involved males and that got me to wondering why...

When the incident occurred, eye witnesses told me that the individual was draining a drink with his head positioned backwards with one arm (holding the glass) raised up over his mouth. This got me to thinking along the line of center of mass and stability.

First of all, the center of mass for most girls is lower to the hips, while the center of mass in boys is much higher, more near the chest. Thus while sitting in a bar stool, the apparent center of a man's weight is likely centered more near the top of the back of the chair. Even if he is just sitting there, doing nothing, the stool is more unstable than it would be with a similar sized woman. I would call this state conditionally unstable. It would required some effort for another to topple a male backwards, but it could be done. Now contrast that some one with their arms resting on a bar with another person with their head tilted back and one arm raised up near the head. Suddenly the overall stability has gone into an absolute unstable situation where very little force is required to to the man and his chair backwards...