Curious how much pressure on your thumb should be behind the neck? I feel since I've been working on scales I may be pushing too hard into the back of the neck with my thumb to better control my fretting fingers, it has been getting really fatigued, or is that normal? It is flat against the neck btw, when I first started I seemed to point into the neck with my thumb a bit.

Thanks!

I'd say a bit of fatigue in the thumb is normal until you build up some strength. I deal with a little bit and shake it out occasionally while practicing.

A caveat: if it's beyond normal muscle fatigue (i.e., pain), then STOP IMMEDIATELY. You could be developing a strain and that could take months to heal.

Thanks Farelli! I appreciate it

Thanks for the reply Adam, good to know!

You should be able to play without any thumb pressure, The thumb is there as a guide really. you should be touching the strings onto the frets not pushing them down. Theres a great video of Pebber playing live where he removes the thumb from the back of the guitar and plays like this. He also does it in a speed video on youtube. i guess this would come after a lot of strength training, why not give it a try.

I forgot about that video. I gotta check it out again. I've always had a little tension in my thumb muscles, especially when playing barre chords.

Here's a good one where he's showing how he plays fast, talking about his right hand thumb being relaxed. But at 2:25 in the video at a random point in his runs he brings his left thumb down next to his index finger and keeps on going.

It's also worthy of note that at several points he doesn't have his thumb firmly in back of his middle finger even though it's on the back of the neck. That makes in clear he's not using that much pressure with that thumb.

Check out at 1:05 . Actually better than that just watch all three just soloing videos they are just mind blowing.