The thumb is a critical part of a balanced left and right hand. Unfortunately, creating a balanced thumb on both hands can be extremely difficult. In many cases the thumbs exert too much force on the neck or frog, resulting in the them hyper-extending or over flexing to the point where they are immovable. This causes the rest of the hand to tighten, largely in the palm, limiting the flexibility and adaptability of the rest of the fingers. In other words, hyper-extended thumbs