The effect of this previously invisible shoe instability defect is astonishing.  It must cause many, or potentially even most, of the serious falls that resulted in $129 billion in medical care costs due to 1,400,000 hospitalizations, 6,460,000 ER visits, and 40,000 fall deaths in 2019 in the U.S. (CDC data).  To put that death toll in context, 43,000 traffic deaths occur annually in the U.S.

The instability is due to a fundamental defect in the basic structure of the footwear sole, an ancient cobbler design at least 2,000 years old.  Long hidden in plain sight, shoe sole’s inherently unsafe instability is finally made obvious here for the first time for all to see.  Until now it has been completely overlooked by the footwear industry, which must therefore abruptly face an inconvenient truth: the dangerous defect must be fixed with the greatest possible speed, given the clear evidence of its terrible cost in lives and medical care!   But the footwear industry and academia have done no R&D on the defect, so how can it be fixed?