I was reading an article the other day about the foot and intrisic muscles to gain more insight into the function and how to re-train these muscles. I am having a difficult time trying to give patients exercises for intrisic muscles when everyone seems to say something different. The most recent I have read is that the best way to retrain the lumbricals is stand on your toes and walk up steps. I can see some logic in this but also seems a very generic exercise and would encompass alot more flexor driven muscles that are likely already strong. I was wondering if you have a more specific exercise that would be simple and easy for patients to do?
Dear Lumbricals
We would have to agree with you that the exercise is very generic and would cause overuse of the flexors, though it would stimulate lumbrical function.
As you are aware, the lumbricals attach proximally to the sides of adjacent tendons of the flexor digitorum longus (with the exception of the 1st, which only attaches to the medial side) and attach distally to the medial aspect of the head of the proximal phalynx and continue on to the extensor hoods in toes 2-5 .
Their typical function is described as flexion of the proximal phalynx and extension of the proximal and distal interphalangeal joints. They have the unique ability to compress the metatarsal-phalangeal and inerpahlangeal joints. There is also a small adductory moment to counteract abductory shear, due to the tendon passing medial to the metatarsal-phalangeal joints (michaud). These are open chain functions. Unless you are in the habit of waving to people with your toes, they often are used quite differently. But this brings upa good point and excellent exercise we call “waving the toes”.
They are performed by holding the great toe in dorsiflexion (hopefully, without assistance) and flexing the other toes at the MTP joint, while keeping the PIP and DIP in extension. This requires and intact and functional EDL (with good motor control!)
Another exercise is sitting with the foot relaxed and concentrating on flexing the toes (2-5) without clawing (similar to above, without the Hallux extended.
Remember they work from mid to terminal stance, but you need to develop skill before endurance or strength.
We hope this helps,
The Gait Guys
