Opposable thumbs are one of the defining characteristics of being human, so it stands to reason that they play a significant role in you being able to do all the things that humans are supposed to be able to do: grab stuff, throw stuff, climb stuff, and bust out the occasional set of push ups.

The video below will explain how to discern whether your thumbs are working for you or against you in the continuing quest for strong, injury-free wrists. If you’d like a little background on how the techniques discussed in the video works, read on!

These are the flexors of your fingers; you’ll notice that they hike on up all the way beyond the elbow joint to the humerus.


These are the flexors of the thumb; you’ll notice that they don’t.


The same thing is also true for the extensors:


fingers . . .



With fewer joints to spread over, the thumb has a greater influence on the joints that it does cross. These local attachments—combined with a unique oblique position in the hand—make the thumb weak in flexion and extension but a one-digit army when it comes to providing leverage in rotation. The thumb’s direction of action acts like a switch, preparing the wrist for either external or internal rotation—and we all know how important that is.

And above all remember that the fingers—including the thumb—are first and foremost information gatherers. The finger tips are instruments of astonishing sensitivity, capable of sensing ridges as small as 13 nanometers in amplitude. According to researchers from KTH Royal Institute of Technology in Stockholm, “this means that, if your finger was the size of the Earth, you could feel the difference between houses and cars. A human being can feel a bump corresponding to the size of a very large molecule.”

molecule, people.

By being smart about how we orient the fingertips under load, we can use that sensitivity to discover new ways of bearing that load comfortably. Enjoy!


7 Responses to “Flexible Thumbs Make Stronger Wrists”

  • Erick

    This was a great article on thumb, finger and wrist function. I’ve had tons of trouble with my right thumb for the last year. I worked on the ideas here and did make some progress in gaining flexibility of my thumb, but not as much as I would have liked. I ended up working on them in a standing position using the wall instead of the floor, and trying it with my arm straight out to the side, elbow bent, and other positions. It seems that tight internal rotators at the shoulder are a problem and standing to use the wall allowed me greater control over rotation of the head of the humerus, which then allowed me to get the movement I was lacking in my thumbs.

    Great info, too bad more people aren’t aware of how big of a role the fingers play in wrist and elbow function.

  • Craig

    Hello Kevin, thanks for the great video. I am at the point where I can’t get my wrist down even with IR. Should I take some time and stretch the muscles and keep working through the position as much as I can?

    Thanks, Craig

  • Carol

    Hi Kevin. I have a question; when I do this video, I can get my whole hand down and continue flexing the distal joint of the thumb, but my thumb rotates so that when my hand is down I’m on the outer side of my thumb, my knuckle “wrinkles” no longer facing up. Is this okay/normal/desireable? My joint is still flexed.

    • Kevin Moore

      The rotation you are describing is a common compensation for a lack of internal rotation at the wrist. If the mobility isn’t there yet to be able to prevent that rotation, try working the stage where you lean away from the hand in order to dramatically increase the internal rotation of the wrist so that the thumb pad/medial palm is, momentarily, the only contact surface. Does that make sense?

      • Carol

        Does that make sense? Not entirely 🙂
        I’m not sure if you mean internal rotation at the wrist (is there such a thing?) or pronation of the forearm or int. rotation at the humerus. I can grasp my thumb and twist it – and I suspect there might be a lack of ROM at this area. But I’ll keep playing with it. Thanks for the reply!

        • Kevin Moore

          I mean pronation of the forearm, Carol. The only reason I didn’t say it that way is because I want to differentiate between the action that takes place at the site of the wrist—which we want more of—and the action that takes place at the elbow. If you skip to 4:15 in the video, notice how when I pull away from the hand the relative position of my forearm to my hand is deeply pronated, but the relative position of my forearm to my humerus is unchanged. That’s what I’d encourage you to play with while you’re searching for that ROM. Good luck! If there’s anything I can do to help, say the word!

  • Tam Gronewold

    I cannot wait to try this in my classes! I was so disappointed too miss your class, but I’m not giving up!


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