Off the shelf orthotics

Depends.

 

Robert is quite right - it depends. Since about 1/3-1/2 of the worlds population have fet that could be defined as flat, it is not biological plausible that they are all abnormal. It is really as simple as that.

 

Mine are. Very bad. Never found a prefab that's comforable or resolves symptoms. For me it's 4mm poly 6 degrees inverted 4 mm medial heel skive. And I'm running a half marathon in 2 weeks on these feet.

As they say- horses for courses.

 

They're not the best on hard, flat surfaces.

They do the job of conforming to the supporting surface well, but at a cost, usually increased lower limb internal rotation and poor propulsive phase during gait.

Not bad on a mixture of soft, hard and undulating surfaces though - think about it:drinks.