Thumb position when soloing (or performing scales) on electric guitar

Question

Why do so many top top electric guitar players (like Mark Knopfler and Eric Clapton) consistently hook their thumb above the neck when it goes against the conventional wisdom?

This seems especially prevalent when they are soloing (like playing scales) vs. playing rhythm (chords). Is the thumb-behind rule less clear-cut for lead/solo/scales than rhythm/chords?

I am looking for a detailed explanation of the pro's/con's of thumb hooking over, not an explanation of why thumb-behind is a "good technique". There are a million explanations of why thumb-behind is considered good. There must be at least some (perhaps minority view) school of thought behind the alternate technique as its use is pervasive.

1. What are the pros and cons in the context of the style of music and soloing shown in the two videos below?

2. How big of an impact will each way make on the ability to play solos like those?

3. Is this a case of where the top guys are advanced enough to be allowed to break the rules?

Here are two examples:

1. Mark Knopfler:

2. Eric Clapton:

Answer 1

See also: How to play power chords without fretting hand getting tired?

To me it completely goes along with conventional wisdom. The difference is what you are looking at the wisdom for.

Hooking your thumb over the top is a lot more comfortable and keeps you from dropping your wrist.

More importantly, it lets you use your thumb as leverage for bending notes. When you get to higher string gauges and/or compound bends, it helps to have the extra force from the thumb squeezing down while your fingers squeeze up.

I think you'll find most of the great rock guitarist use thumb-over when soloing, and actually are more likely to put their thumbs behind when playing chords that require the index finger on the low E string.

What are the pros and cons in the context of the style of music and soloing shown in the two videos below?

I think the pros I've outlined. One con is most guitarists can't reach the low E string with their third or fourth fingers when their thumb is on top, and the first finger may have very little power when stretched out to reach it. Another con is when you have your wrist up, you can't stretch your fingers as wide to cover as many frets, and there are some "stretch" fingerings that are difficult to impossible with a high wrist and thumb over the top.

How big of an impact will each way make on the ability to play solos like those?

Personally I can't imagine trying to play rock solos with bending without my thumb over - especially with thicker strings and/or larger bends. I pretty much have to play thumb over as much as possible or I have problems with my wrist. Beyond all of that, thumb over is much more comfortable when you wear the guitar as low as they do. If you want to play like the great rock guitarists, it does help to adopt their techniques. This is one I have recommended to every single guitar student I've ever taught.

Is this a case of where the top guys are advanced enough to be allowed to break the rules?

No, it's the opposite. These guys are experienced enough to know that the rule is actually you should have your thumb over the top as much as possible. Jimmy Page, Jimi Hendrix, and Stevie Ray Vaughan all fretted the low E string with their thumbs over the top while playing certain chords (I also do that routinely but I doubt many will be impressed by that fact).

Answer 2

The recommendation to keep your thumb behind the neck is a holdover from acoustic guitars. Ideas from acoustic playing are still used to inform electric guitar technique despite the change in technology.

At a mechanical level, the smaller size (nut width in particular) makes it feasible to wrap your thumb around the neck (try that on a classical guitar!). The thinner strings (compared to steel string acoustic) makes bending strings feasible. As mentioned in other answers, wrapping the thumb provides additional leverage for doing this. Electric guitar technique and style has evolved in relation to these technical changes of the instrument.

However, culture (and pedagogy) are slow to change, hence there are still recommendations to keep you thumb behind the neck.

Answer 3

As I wasn't getting any bites on this question, I kept digging and I think I've come across an explanation myself. Anyone else, please chime-in and correct me, if this isn't right (or there's more to it)...

It seems there is an explicit technique known as "The Stevie Ray Vaughan Grip". There are videos about it on YouTube (such as below), including folks selling lessons on the technique. It seems especially appropriate as they talk about fretting the 6th (and possibly 5th) string with the thumb, which looks like Mark and Eric may be doing in the videos above.

Answer 4

Whether or not there are technical advantages to thumb-over, I think most players gravitate to it because it's the most natural and comfortable way to hold the neck, like holding a baseball bat or tennis racket. Moreover, if you like to fret chords with your thumb on the E string, your hand tends to linger in that position afterward because it's so comfortable. Even on classical, new players find themselves bringing the thumb over, even though everyone agrees it's a bad idea on classical because the neck is so wide.

You see it even more on electric because the neck is so thin, and fretting is so easy from any direction, that it doesn't really matter where you put your thumb. You could practically fret with the back of your hand and do fine. So you find a position that's comfortable and don't bother to refine it.