@David Smith,
I am not really sure where KE (which I assume means Kinetic energy) comes in to the calculation.
Assuming the sole is approximately elastic, there is an easy relationship between work and amount of deformation. But there will be multiple forces doing this work including forces from and varying share of weight, and actions of muscles.
It will be difficult to deduce much about any velocity involved from these measurements.
This calculation will only get you the small proportion of work done (and energy used) to deform the soles.