Sitting correctly will help guitarists avoid many technical problems. If the guitar is not placed correctly the hands are forced to do an enormous amount of extra work. The sitting position should allow a player’s hands to have no role in holding the guitar in place. The great guitar masters of the 19th century describe the hands as being like ballerinas dancing across the string, weightless, and without extra tension. In order to achieve this, we need to support the guitar by means of correct placement.
The first thing one notices about a classical guitarist is that they have their leg propped up on a little stool. The footstool is one key in placing the guitar in the optimum position. The footstool is placed under the guitarist’s left leg raising it usually six to nine inches. The exact height will be determined by several other factors including personal preference and comfort (more on this later). The guitarist’s right leg goes straight down to the floor or slightly back. Sit up straight, feel as if your head is being pulled up towards the sky thus straightening out one’s spine (Kind of like a puppet on a string). The guitarists shoulder’s should be relaxed and free from excess tension.
The guitar should come in contact with the player in four points. The curve of the guitar fits onto the guitarists left leg. The other side of the guitar body hits the right leg. In other words the guitar should be more or less between your legs and centered not off to one side or the other. One of the most common mistakes guitarists make is to but the guitar on the right leg, with the neck pointed toward the ground and too far for the left hand to reach. The back of the guitar comes to rest on the players chest. There should be a pocket of air between the back of the guitar and the player’s body. Notice that the guitar is at a slight angle slightly up towards the ceiling. The final point of contact is the right hand forearm. With just a little weight by this arm the guitar should stay in place. Notice that the left hand has no role in holding the guitar in place. Thus the hand can concentrate on flying across the fretboard in feats of acrobatic splendor ( Or more importantly reach for a cold drink during those long hours of practicing)
At first when a new player is presented with all the details of how to sit they often feel like a greek statue. It does take some getting used to, but the results are worth the effort. Better sound and easier playing along with reduced risk of injury seem worth the trouble of feeling like a chunk of marble. Speaking of marble, try not to be too stiff about it all. The player’s body should fell poised ready for action, but not rigid. Just enough tension, not too much or too little is the rule for most of guitar technique.