Subvisual Haze

Everything is energy transfer.  Even you just standing in place requires your body to withstand the internal stress of perfectly opposing gravitational and normal forces.  Your feet hurt, your joints get sore, your spine slowly compresses etc.

How do you think it would feel if gravity was suddenly 6 times its current strength?  That's roughly the situation occurring here.  No net work does not mean the forces disappear, just that they don't generate a change in kinetic energy/acceleration.   Instead they would exert a painful sustained stress on the allomancer's body in the horizontal plane, in this example one roughly 6 times the force you normally feel when gravity and normal force counter one another to keep you from falling through the Earth.

The question just becomes if the body in question is experiencing 6g tension or compression.

It's true the net force would result in zero net acceleration, but the energy of those forces just don't vanish though.  The allomancer here is being simultaneously pushed/pulled in 2 opposite directions at 6 g-force each.  OUCH!