Questions for the shredders

I am trying to build up speed on the electric guitar and notice that as I go faster the neck of the guitar bounces around a little due to the counter-play between my fretting fingers and my thumb supporting the back of the neck. I get more stability if the upper part of the palm of my left hand also counterbalances my fretting fingers. Is this a bad habit?

Also, I notice that many of the fastest shredders have their left thumbs up over the neck of the guitar, which seems to violate some people's rule for building speed. Any thoughts?

Depends where on the neck you are playing and also how big your hands are. Wrapping your thumb around the neck is bad if you do it for everything, but necessary sometimes for comfort or reach reasons.

I wear a size large glove and do find it difficult to have my thumb on the back of the neck at all times when doing scales. The thumb over the top of the neck relieves some tension.

I can't make referrence to wearing a glove, I am a conventional bear hander. Also I don't believe your fretting hand is for supporting the guitar. That's the strap or knees job. The thumb behind the neck is used to apply pressure to the frets. The thumb around the neck is most often used to dampen the E string.
Maybe re-adjust your strap or find a different knee position. Hope this helps..
Gordon

Its a re-occuring habit that I can correct quickly but need to curb soon. I have students who have similar issues with whom I am working to fix.

This is an ongoing debate unfortunately; a debate for which there isn't necessarily a definitive answer. Through my own experience, and from the questions I have asked, it seems that it simply pertains to what you are playing and what is most comfortable.

A more formal approach, ala classical, may suggest you play with your thumb behind the neck all the time and keep it parellel with your fretting hand pointing inward. However, the rock gods we all know and love use their thumb all the time and you will see this technique across the board in other styles as well.

In my opinion as long as you keep your thumb pointed inward, whether that be behind the neck or wrapped around, you are good. Don't neglect how you are sitting when you practice, or your posture either. Those things are just as important to monitor.

I checked out some of the shred lessons on the site, and each of the teachers seem to apply different techniques. Some keep the thumb behind the neck, and others wrap it around. The tougher shred stuff will take more of a behind the neck approach, but the more bluesy licks and pentatonic licks are helpful with the thumb. It applies to what you are playing.

Hopefully this helps. :D

Makes sense, especially about the thumb pointing in. I got in the habit of pointing the thumb out so there were different stresses on the hand.

I've been stuck on a certain speed (160 bpm, 1/8th notes) for a while now so I'm trying to drill down to what is causing the block to break through to a new level.

Thanks for your reply!

No problem sir :)

The thumb behind the neck bit is really an obstacle, so again make sure your thumb is not pointing up towards the headstock at all. Try and keep it parellel with your other fingers, and whether you are behind the neck or around it; you have much better technique.

Best of luck