I normally run 2-4 miles/day, but recently I began noticing that it is difficult for me to dorsiflex my foot (lift foot up at the ankle) while running, causing foot drop as I am extending my left leg during my run. It heals within 30 minutes after I finish my run, but it severely limits my ability to run the distance I want.
I am assuming it is a weakness or injury to my tibialis anterior muscle, but I am not totally sure. (Does not feel like shin-splints)
Anyone have any suggestions for stretches/treatment for this?
I'm assuming you tried rest, and may have rubbed it some. I would examine it slowly under pressure for signs of trigger points in the Tib A, but stiff plantarflexors are often to blame for trouble with dorsiflexion due to tiring of the Tib A.
As you know, since you mentioned "foot" rather than feet, there could be scar tissue from an old injury interfering with the Peroneal Nerve function that could lead to a case of chronic "drop foot." Not saying massage is always the answer to that, but there are techniques such as ART focused on removal/amelioration of adhesions due to improper scarring.
If you work out on a track and the problem occurs in the right foot, I'm leaning towards antagonist muscle stiffness, but if your runs are without the repetitive left turns of a track, my money is on some neurological component, including interference by scar tissue in the leg. There can also be circulatory issues that can be easy to diagnose in a physical exam. Not sure of your age/health, but stroke has been known to bring about this condition as well.
Look for the easy stuff first. In my opinion, a stretch would be counterproductive when a muscle fails to contract. Look for muscular dysfunction, a hyperactive antagonist muscle (Soleus, rear calf), circulatory differences between legs (temperature, "pinking" of extremities), and leave scanning for scar tissue to a pro. Since nobody is going to rip it out and show it to you, it requires some faith in your provider that scarring is present. If that is really the problem, there can often be a dramatic turnaround after targeted therapy. If it's not, don't waste your money or risk further injury. Minus any solid conclusions at this point, I would pursue a neurological test.
I am encouraged by your report that it "heals" after rest. This may point more strongly to muscular dysfunction, or may suggest an inflammatory component, perhaps combined with scarring, that affects the nerve. At this point, I'm thinking more muscle than nerve. Just do the homework, or have a good PT or sports doc take a crack at it.
There are many potential causes of "foot drop" The fact that it is occuring on just the left, suggests possible nerve entrapment. Nerves can be entraped at different locations, if you have a history of back pain and sciatic, this should be considered. There are other explanations for foot drop such as neuropathy (genetic disorders, or diabetic). If there is a medical history related to possible perpherial neuropathy start with your primary care physician. Stretching exercises is NOT the answer for foot drop. It is unlikely that additional strengthening exercises is the answer.
Damien Howell PT, DPT, OCS
Interesting that Damien mentioned potential spinal causes for what is called a "foot drop" condition. Most people have legs that slightly differ in length, one from the other, a.k.a. "leg length discrepancy." In your case, a longer left leg would require more dorsiflexion to prevent the left toe from dragging. While this could tire your dorsiflexor muscles, leading at least in part to your symptoms, there is a potential double-whammy. Unilateral problems often result when the spine curves to one side, and the spine usually curves toward the side of a longer leg to compensate for the tilting of the pelvis. However slight that curve may be, it can exacerbate, or even be the root cause of (so to speak), nerve impingement. Furthermore, a curve in the lower spine usually results in compensatory curves in the upper spine, which can aggravate spinal stenosis there, even when no lower spine pathology is present. A technically informative article on the potential contribution of upper spinal causes to foot drop is found here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2031999/
I'm with you in thinking that you have "run" into a muscular problem, because the effects of the more common and even the rare neurological causes would tend to inhibit your expectations that you could even run at all. There is that possibility though, of gradual onset of symptoms due to things long in the making. I sincerely hope yours is a simple case of tired muscle, but as you can see in the above article, a great deal of work is necessary to rule out all possible causes. I wish you and your chosen healthcare provider(s) the best of luck in that quest.