Arch collapse sounds possible and the peroneals would be a major player in that. Before bringing in something like orthotics, I would ask the big question of why? What is not functioning in your body that causes your arch to collapse? It tells me that you have some movement dysfunction, more than likely at your hips, and the peroneals are kicking into overdrive to compensate. I would look at the quadratus lumborum and your ability to hike your opposite hip up during load phase of gait. If your QL is off, which is very common, your peroneals may be stabilizing for the QL. Adding orthotics will provide a temporary short term remedy but create longer term issues. Primarily, as Jim above mentioned, weakened musculature in the lower leg and foot.
I suggest finding a highly skilled movement therapist who can properly assess your movement quality. Find out what is not working and who is compensating. They can then offer a corrective strategy to release the problem muscles and strengthen what is weak. With a sound treatment strategy, you may see almost immediate changes in your arch.
Jesse James
