An arm rest is an attachment to the top of the guitar that allows one to experiment with right hand positioning and arm/fulcrum placement.
People with longer limbs (forearms) are generally at a disadvantage when trying to achieve a relaxed/balanced right arm positioning on the "full-sized" classical guitar.
It was invented for the classical guitar but can be used on any guitar where a more comfortable position is desired.
The classical guitar was standardized in size in 1860 for the average-sized Spanish musician of the day, who, at that time, stood approximately 5'2" to 5'4" in height. The original intent was for the bicep to rest on the highest part of the bout. This would allow the weight of the limb (shoulder, tricep and bicep) to rest on the top of the guitar and be as relaxed as possible. It would also allow the entire forearm to be free and relaxed and place the hand over the sound hole. This positioning works wonderfully for people who are approximately 5'2" to 5'4", or who have short forearms.
Traditionally, this type of arm placement has been called "the long arm approach." It uses a fulcrum much like a pump handle or wheelbarrow.
It allows one to use the minimal amount of "active muscle tension" to maintain their right hand playing position.
Yes, the longer your limbs are, the more you will have to use this approach.
Since 1860, Europeans and Americans have steadily grown taller. Longer-limbed people have to use a different fulcrum. Instead of using the "pump handle" or "wheelbarrow" fulcrum, they have to use a "teeter-totter"-like fulcrum in arm placement.
Generally, a player with long limbs will place his right hand PIMA on the rear portion of the sound hole on strings "D," "G," "B," and "E" to achieve a "standard tone." If they keep their wrists fairly straight and avoid excess flexion (bending) in the wrist, a person with long forearms will have a fulcrum somewhere between the wrist and the elbow. This type of fulcrum is called "the short arm" approach.
Generally, if you're using a fulcrum like the teeter-totter (short arm) you're working weight one way and then the other. In other words, while resting between the wrist and elbow, the elbow acts like the bigger child on the teeter-totter, thereby lifting the hand off the strings (in a relaxed position). This is especially true if your fulcrum is midway between your wrist and elbow. In this position, one is holding tension in the shoulder, triceps, and biceps (just to counteract the teeter-totter-like effect of this fulcrum) to maintain hand position on the strings.
If I were to ask you to hold tension in your fingers and move them as fast as possible, you would never be able to "access" the fast muscle fiber nerve twitch that you would have if you held your hand down by your side (with no tension in your muscles and hand) and moved your fingers back and forth as fast as possible. You would be quicker and lighter in this position.
In the short arm approach, one is holding more "active muscle tension" in the limbs to maintain right arm/hand positioning. This approach never allows one to feel the "lightness of touch" because of the muscle tension you are using in your shoulders, triceps, biceps and forearm to maintain hand position. This is why some people never feel able to completely relax in their positioning. They're never able to let go of the excess tension inherent in that positioning. Of course, the longer the forearm is...the worse it usually feels.
The classical guitar works in a way that the more tension you hold in your hand/limbs...the more the guitar balks. The lighter touch you have, the more the guitar will cooperate and allow your playing to soar.
Yes. First of all, one has a 90-degree edge "digging" into the tendons of the forearm. Although research needs to be done to see how this affects the tendons, the result of the tendons moving across a sharp surface for thousands, or even millions of times, cannot be good. In recent years, not only has Carpal Tunnel Syndrome (usually the result of excess flexion/bending of the wrist) plagued guitarists, but a more debilitating condition has arisen for those playing with and holding excess tension in their positioning. This condition is called "Task Specific Focal Dysphonia, " commonly referred to as "writer's cramp." The effect this has on the finger digits varies widely from individual to individual. It produces unwanted movements in the finger digits whether playing or relaxed. The effect that this 90-degree edge has on the tendons...I believe...has not yet been fully understood or comprehended in regards to the detrimental effect it may have on one's guitar playing now...or worse, in the future.
Certainly this would help shorter-limbed players, but the physics of forearm limb length, and holding and maintaining hand/arm positioning, would still come into play for longer-limbed players.
It would open up the possibility of finding a right arm/hand placement and fulcrum that would allow you to let go of excess muscle tension, feel the lightness of touch to which the guitar responds beautifully, and achieve a comfortable and stable positioning. In general, the arm rest allows a player with longer limbs to achieve the same relaxed positioning as that of a shorter-limbed player.
It opens up the sound of the guitar because of the forearm being "off" the soundboard. You could compare it to the effect a hand has on a tuning fork. When a tuning fork is struck, the fork vibrates for quite a while. If you were to touch a tuning fork immediately after striking it, you would decrease the vibration substantially. One's forearm essentially does the same thing to the soundboard of the guitar. The guitar is muted and sustain is decreased when touching the soundboard. I always tell people...a trumpet uses a mute but doesn't play with one all the time...a piano has a mute pedal but pianists don't use it all the time...why would you always play the guitar with a mute (forearm)? You would play the guitar that way because, before the arm rest was invented, that was the only way to play the guitar. The arm rest increases the clarity, sustain and tone of any guitar.
If you have a semi-gloss or French polish finish, the suction cups will work great. If you have a satin finish, the cups will not stick because air "leaks" in around the porous wood and loosens the suction cup.
When the cups are attached to the guitar, care should be taken so that no moisture is trapped between the cup and the finish (i.e.: licking the cups or wetting the cups to provide a seal.) If there is moisture between the cup and the wood, and the cup is left on the guitar for over 8 hours, a moisture mark may result.
The leg rest is for any acoustic/classical guitar player who wishes to sit in the classical position.
It replaces the traditional footstool, and is much like the A-Frame or Dyna-cushion.
The leg rest is designed so that, in essence, a "gimbal" or "u-joint"-like movement is easily achievable. The leg rest utilizes a "yoke and tang" design, allowing this type of movement. The leg rest is sold as a kit, which comes with 2", 3", 4" and 7" struts. One can experiment with any 2 different strut sizes to achieve their optimal playing position. It has more adjustability and creative possibilities than any other similar product on the market.
The belt clip feature allows a player to fasten one end of the clip to the belt loop on their pants, with the other side attaching to the underside of the leg rest.
Once basic positioning has been achieved through experimentation with different strut sizes, one can use the belt clip for holding the guitar in an extremely secure position One can lean back in a chair, or play on a bar stool. Once the belt clip is fastened and clipped into position, a player can rest assured that the guitar will not slip away from them. It also allows one to release left hand tension that sometimes happens inadvertently by holding the guitar in position. Once people use the belt clip...they're sold on it.
All one has to do to release the clip is to press the underside of the clip on the leg rest until it releases. Then you're free to stand up, take a bow or get a cup of coffee.
There is foam padding on the underside of the leg rest. The foam padding provides an anti-skid surface for the leg rest. However, you'll find that if you choose not to use the belt clip, the leg rest may not be as secure. I HIGHLY RECOMMEND USING THE BELT CLIP. Of the other adjustability features of the leg rest, the belt clip is one that, by far, sets this product far above any other similar product.