Puppetry is NOT easy. It's hard work. You're not just acting anymore, you're acting through your hand! LOL!!
As far as endurance is concerned, while teaching puppetry classes I've told kids to just start putting a sneaker on their hand and holding it over their head for the duration of a commercial. This helps as time progresses. I've also taught them about crossing their fingers so they don't get the flipping-of-the-lid going on, and exercising. Practice makes perfect, and when you DO think you're perfect, you still need more practice! (obviously, there's a TON more to it all than just this).
The Muppeteers DO make it look easy, and that's because they are so talented. If it didn't look easy, they wouldn't be doing their awesome jobs that they do.
David, SS did say he's not a Muppeteer in the title of his above thread; but, that still doesn't mean he's not a PUPpeteer, so...good question.
I'm just thankful SS comes around and shares info with us.
I miss Jerry and Karen, too. They used to show up a long time ago and help with info.