When the Short Toe Extensors Try to Rule the World !
A case of a runner with forefoot pain.
This is a runner of ours, one of the fastest young men in the state of illinois, top 10 in the country in mid-distance, top 20 in the USA in cross country.
He came in with left forefoot plantar pain. He explained (in a matter of words) that he was having pain at full forefoot loading at heel rise /push off.
We watched him walk, saw this visual problem present itself in dynamic motion (yup, no stop frame video on this one, not when you see it about 10 times a month !) and noted a subtle left lateral hip/pelvis shift past what would be considered normal for frontal plane mechanics.
On the table this is a photo of his feet. What do you see ?
We see a suspected (which you will try to confirm on examination) increase in short extensor (EDB, extensor digitorum brevis) muscle tone. Increased long extensor (EDL, extensor dig. longus muscle) tone would have represented itself with the distal toes also extended but here we see a relative dominance of the long flexors (FDL, Flexor dig. longus) with the heightened short flexor increase.
We also see more confirmation of heightened long flexor tone (FDL) by the degree of heavy callus formation on the very tip of the 2nd toe (it was on all 4 lateral toes but the photo is not clear enough to demonstrate). You can also see supporting evidence of heightened long flexor dominance by the subungual hematoma (bleeding under the 2nd toe nail). (How does this correlate ? Well, in most runners with excessive long flexor tone/use not only do they flex and claw so much in the shoes that the callus is on the tip of the toes but the nail also begins to lift as the nail is caught on the sock liner of the shoe as the toe flexes, slowly, mile by mile pulling the toe nail from the nail bed thus bleeding underneath it). Yes, it is NOT from the toes hitting the front end of the shoe !
Our examination confirmed weakness of all lumbrical muscles and of the flexor digitorum brevis and lateral quadratus plantae. The patient could feel the strength/engagement difference as compared to testing on the right foot of the same muscle groups (we always compare side to side, for us and for the patient’s awareness). The extensor digitorum brevis muscle mass on the lateral dorsum of the foot was tender as were the tendons along their course. There was also weakness higher up in the kinetic chain at the lower division of the transversus abdominus and internal abdominal oblique, and frontal plane hip stabilizers (gluteus medius; anterior-middle-and posterior divisions).The 2nd and 3rd metatarsal heads were remarkably tender to palpation and it was obvious that the metatarsal fat pads had migrated distally from the lumbrical muscle weakness.
Sometimes a grasp response by the long flexors can represent a propioceptive /balance deficit during single leg stance phase so be sure to test those centers as well (cerebellar, vision, joint position sense, inner ear-vestibular apparatus).
So, what is the take away for the non-medical person, the runner next door if you will ? Lets just say, symmetry wins and when asymmetry is apparent, bring it up to the people that do your body work. Hopefully, what you and they see will be assessed in a clinical light, and as a team you can get to the bottom of what is not working…….and in this case…..what was causing not only the plantar foot pain, but the left lateral hip sway outside the frontal plane.
———we are, The Gait Guys……Shawn and Ivo