If your pain is accurately described as a cramp, it is quite possible that you are speaking of a muscle spasm. The only muscle that could be considered on the top of the foot is the Extensor digitorum brevis muscle which resides in what is know as the sinus tarsi, which is located quite closely to what could be described as the top of the foot, and just lateral (outside) to the longitudinal mid-line of the foot. (sorry for the medical lingo, but it is the most effective way of describing location).
It is premature to assume that this is the actual locus of cause, but assuming that it is, it is not uncommon for this muscle or its tendons to become strained and inflamed, especially if there is some abnormal foot motion going on. Running is not fast walking, and an analysis of your run gait might be required.
Again, it is premature to suggest therapy, and please do not attempt this at home without the advice of an examining physician, but various modalities such as PROPERLY employed heat and/or ice as well as possibly muscle relaxants, sometimes corticosteroid injection and, of course a gait analysis may be helpful.
But other than for an academic discussion of what your stated symptoms might indicate, real diagnosis and treatment will require a hands-on diagnosis. As with the definitive diagnosis of most foot problems, a trip to a podiatrist, particularly one who is well-versed in treating runners, is in order |
