At the local Cello Thumbs Anonymous meeting…
Hi, I’m Mark and I play cello with too much left thumb.
All kidding aside, I’ve been aware for some time now that I use too much pressure with my left thumb while stopping the strings with my left fingers. Enough so that first thing in the morning my thumb is stiff and sore. It always loosens up within a few minutes of waking, but it is indicative of improper technique.
I’ve talked to my teacher about it and tried to correct the habit unsuccessfully until now. Tonight I played most of my 45 minute practice without my thumb on the cello at all. My intonation suffered somewhat, but I was able to play. Previously I found that the cello’s endpin would squirt away from me when ever I tried playing without my thumb. Tonight I washed my little square pin rest so it wouldn’t slide on the wooden floor, And I tried to only pull as hard as needed and no harder.
By and large it was successful. Several hundred more practice sessions and it should start to feel normal.