mr dave

actually it's the musicians in the video who are using 'bad' technique. wrapping your thumb over the neck of the instrument is rarely recommended and especially not if you have small hands. you basically need to wrap your hand around the neck and grab it more like a baseball bat. your index finger should only be able to reach the D string when trying to form chords when using this method.

the 'benefit' to the method is that is frees up more range in your fretting fingers so that you can play more Hendrix-isms on the higher strings. what your thumb ends up doing is sounding the root note to the chord and muting the A string so you end up with a chunky/percussive element to the base of your chord while being able to add all sorts of accents over top.

the downside is that it's really easy to mess up your wrist if you're doing it wrong or forcing yourself as you cease using your thumb to reinforce your hand and its position on the neck

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