I've had three Thumbs - an '03 BO 6, a '93 NT 6, and I forget what year walnut 5. Fabulous instruments. However, I started having some shoulder trouble, probably from something not bass-related, and I found that the Thumbs really exacerbated it. I would go to church on Sunday, rehearse for an hour, play through the service, and my left shoulder would hurt for days. I finally figured out that it was the "reach" down to the low notes that was doing it, along with the neck dive. I finally sold them off, and since then I've been playing basses with a longer upper horn, and my shoulder seems to have healed. It took many months to loosen up, but now I have no pain from playing. I love everything about the Thumb, except the pain. Anyone else have physical problems associated with one style of bass?