Tendons run across the top of the foot, extend down from the muscle in the front of the shin, and split off into each digit. These tendons work to straighten each toe, pull each toe up, and to help move the entire foot.
Just like any other tendon in the body, the tendons in the feet can become inflamed. When they do, the symptoms can be very similar to the pain of a stress fracture. How can you tell the difference between the two? Because the extensor tendons raise the toes, if you have someone apply pressure to your toes as you raise them and that isolates your pain, chances are you have a tendonitis issue rather than a stress fracture, which would be more pain on impact.
Causes of inflammation can be traced to improper shoes, a tight Achilles, and weak or tight calf muscles. Ice the tendons to reduce inflammation, make sure your shoes have enough support—again, an insert may help—and be diligent about stretching your calf muscles and completing calf-strengthening exercises.
Adductor and Abductor Hallucis
The adductor hallucis is a muscle that runs horizontally across the top of the foot, forming a V-shape with its center at the big toe. The abductor hallucis runs lengthwise on the medial inside of the foot along the arch. Pain in either of these two areas can feel like extensor tendonitis or plantar fasciitis pain. But, runners can clearly identify a tight and sore abductor hallucis from a plantar problem because the muscle isn't on the bottom of the foot but rather on the inside of the arch.
Problems with either of these two muscles can result from not having enough arch support in your shoes, but most typically if you have bunions. Expert sports massage therapist and Rolfer Allan Kupczack, who treats recreational runners and elite athletes like Kara Goucher, explains that a tug-of-war that can occur.
"When the adductor hallucis is tight and pulling your big toe towards the other toes, it eventually creates a bunion. The abductor hallucis becomes weak from being in a stretched position all the time, and often the origin of the abductor, down near the heel, is tender."
Treatment for this problem is a two-pronged approach in order to keep both muscles happy.