In my experience peoneal muscle tendon problems are frequently related to habitual sitting postures. Often we sit with the foot tucked underneath the chair resting in a maximum supinated posture laying the base of the 5th metatatarsal directly on the ground, sometimes with the opposite foot resting on top of the injured foot. Ladies with short legs will often tuck one foot under the opposite thigh, again with the foot in a maximum supinated position and the base of the 5th metatarsal is compressed into the chair. This is sub-concious habitual asymmetrical sitting patterns. The peroneal muscles are chronically stretched resulting in "stretch weakness". A smart Physical Therapist should be able to clinically determine if there is a length associated muscle weakness of the peroneal muscles and design a remedial strengthening exercises to strengthen the muscles at thier shortest length.
Bilateral pain at the base of the 5th metatarsal is often related to wearing shoes that are too narrow. Ladies running shoes common in B width, and mends come in D width. Ask to have you foot measured to see if you are in correct size shoes. Make sure you measure both feet do not assume the feet are symmetrical size.
Damien Howell PT, DPT, OCS
www.damienhowellpt.com