I recently attended the Carnegie Mellon Double Bass Symposium. It’s a fantastic event I’ve been to several times, and one session in particular has stuck with me ever since. Kurt Muroki, the superb bass professor at Indiana University Bloomington, dedicated a chunk of his masterclass to something most of us never think about: our thumbs!
That conversation sent me down a rabbit hole. I ended up rigging up a “thumb cam,” a small camera angled to capture exactly what my thumbs are doing as I play, and the results were eye-opening. So let’s talk about thumbs.
Why Should We Pay Attention to Our Thumbs?
As Kurt pointed out, our thumbs are strong. They do a tremendous amount of work in everyday life, and because of that strength, we tend to let them do too much when we play. The bigger problem? We can’t see them. The thumb on the bow hand is hidden from our view, and the left thumb (if you play a right-handed double bass) is tucked behind the neck. Out of sight, out of mind, and that’s exactly when bad habits creep in.
Kurt’s suggestion was refreshingly direct: record your thumb. Make a whole YouTube video of your thumb if you have to. See what it’s actually doing, because I promise it’s not what you think.
The Natural Thumb Position
One of the most useful exercises Kurt demonstrated was deceptively simple: just pick up a glass of water. Or put a bottle in your hand. Notice how your thumb naturally lands on it.
It’s not on the flat pad, is it? It’s more on the side of the thumb.
This matters a lot for double bassists! When we use the flat pad of the thumb, as many method books and early teachers show us, the thumb almost inevitably wants to squeeze. It’s a mechanical reflex. But when you rotate to the side of the thumb, squeezing becomes nearly impossible. The hand just doesn’t want to do it.
Kurt put it well: once you go to the pad, it’s going to want to squeeze. The side of the thumb is your friend.
Thumb Faces Pinky
Another insight from Kurt: the left thumb should face the pinky, not the middle finger.
Why? Because the pinky is the weakest finger. When you orient your thumb toward it, you create a balanced counterforce without tension. When your thumb faces the middle finger instead, the hand naturally starts to grip and squeeze. The joints lock, and two things happen immediately: you lose the ability to pivot, and vibrato suffers.
A locked thumb joint is a vibrato killer. You can hear it and feel it. The pitch stops moving freely through the hand. Kurt demonstrated this live in the masterclass, and the difference was striking.
The Thumb Vibrato Exercise
Here’s one of Kurt’s practical exercises for freeing up the left thumb. On the back of the neck, not on the string, simply practice the vibrato motion with just the thumb. If the thumb joints are aligned with the direction of vibrato, the thumb will move freely. If they’re not, it locks up and refuses to budge.
It sounds almost too simple, but feeling that motion in isolation makes it much easier to integrate into your playing.
Equal Activation, Minimal Tension
What I keep coming back to from this masterclass is the idea of equal activation between both thumbs, and keeping that activation as low and free as possible.
When I get louder in the right arm, I tend to grip harder with the left thumb. Kurt’s antidote is almost counterintuitive: as you add energy in the bow arm, consciously let go even more in the left hand. Think of it as the energy going into the right side and dissipating from the left. It’s a strange exercise, but it works.
The image Kurt used: relaxed enough that you could put a grape between your thumb and the neck without squishing it.
A Note on My Own Playing
Watching this masterclass also made me reflect on my own bow hold. If you’ve watched my recent videos, you may have noticed I’ve been using the Italian bow hold, something I was inspired to revisit by Orion Miller, one of the newer bassists in the San Francisco Symphony. I’ve used this hold on and off over the years, and it’s been working well for me lately.
From the thumb cam angle, you can really see the shifts happening at the bow change: the fingers and thumb actually begin to change direction before the bow does, acting as a little spring between the down bow and up bow. It’s subtle, but visible, which is exactly why the thumb cam experiment has been so worthwhile.
Go Back to the Fundamentals
If there’s one takeaway from all of this, it’s what I find myself saying more and more: the fundamentals are everything. The higher the level of playing I observe, the more I see great teachers bringing things back to the basics: natural hand position, relaxed thumbs, freedom in the joints.
Kurt has a gift for making these concepts feel playful and light while hitting on something genuinely deep. Students at Indiana University Bloomington are incredibly lucky to have him alongside Jeff Turner. What a combination.
We discuss topics like this every week in our email newsletter. We also offer free monthly sheet music giveaways, community news, and all sorts of cool opportunities for bass players. If you’re not on the list, consider subscribing!
