Category Archives: Biomechanics

Hammer On and Pull Off like Bruce Lee!

There are several secrets to successful slurs. For hammer-on slurs, the first rule is to prepare the fingers. Each finger must be in place just above the string to play. Many contend that a significant distance is required to produce a clearly audible sound. However, I would invite them to consult the documents available explaining the famous one-inch punch of Jeet Kune Do master Bruce Lee. He showed that he could throw back an opponent with a punch initiated from only one inch away. Using this technique, he demonstrated the well-known principle in physics (kinetic energy) that it is not necessarily distance that affects force, but the speed at with the object is moving.

So the secret is a good positioning of the hand and a quick descent of the finger led by the first joint. The positioning of the finger must be optimal thanks to the use of the second and third phalanx so that the attack is perfect and there is no energy loss.

In the case of pulled slurs, the fingers should be placed on the string, as the finger that will play the second note is already in place. In this case, it is the second phalanx that act as an engine.

Again, speed is the secret. The finger that makes the downward movement can also use the bounce of the bottom string (which then serves as a springboard) to change direction.

In achieving the slurs, we can also use the pronator and supinator muscles to give a boost to the hand. Under no circumstances should the hand pull the pronator and supinator muscles. These are the muscles that power the hand.

© Jean-François Desrosby (D.Mus.)

Left-arm lateral movement

The secret of quick and efficient movement of the left arm is to use the shoulder muscles to move the arm and forearm. The hand is never the driving force behind the action. It is relaxed, and it is brought into place by the musculature of the shoulder. The forearm is then called upon for a more accurate adjustment, while the wrist and  fingers maintain their optimised positioning as described above.

The eyes determine the end point of the hand, allowing the brain to calculate the distance between the start and end positions easily.

© Jean-François Desrosby (D.Mus.)

Optimal hand position

The optimal positioning of the right and left hand is achieved through compliance with the ergonomic principles outlined in previous post.  The hand must be tilted on the ulnar side to an angle of 15 degrees at the wrist. A slight flexion toward the outside of 15 degrees at the wrist completes the positioning. Although it is impossible to maintain this optimum positioning at all times, the player will attempt to return to this position in which the fingers are free to move as often as possible.

© Jean-François  Desrosby 2015

Right hand

We can apply all the principles developed for the left hand to the right hand. Although the arm is supported on the guitar, we must, nevertheless, maintain tone. This will prevent the arm from relying too much on the guitar, compressing the soundboard and reducing resonance. In addition, several important tendons pass through the point at which the arm lies. Supporting the arm with the appropriate muscles reduces the pressure on the tendons and thus ensures the free movement of those fundamental elements.

The right hand falls into place much more naturally than the left hand. We can optimise the action by applying a slight supination, which increases the agility and independence of the fingers. Although the wrist should be involved in facilitating the passage of tendons, a light ulnar deviation facilitates the movements of the fingers. In addition, by moving the thumb away from the index, we use extended opposition, which promotes the stability of the hand and accuracy.

In addition to extended opposition, other principles can help maximise the action of the fingers on the instrument. Each finger can flex and extend. They can move laterally as well, but also in axial rotation.

The musician looks for a free and quick flexion of the finger. He also looks for a rapid extension without amplitude and a possible side extension of the fingers when necessary, despite bending.

The initial rule is to use the sequential winding of the phalanx. The second phalanx must be the engine of the movement, followed by the first and, finally, the third. This sequence ensures the proper functioning of the intrinsic and extrinsic muscles of the hand. Follow exactly the same sequence to take up the finger. By starting the movement with the second phalanx, we optimise speed.

The rounded balanced hand ensures functional stability. It also promotes the independence of the fingers. As the gaps are difficult when the fingers are flexed, we can facilitate this by flexing the wrist. In addition, the lateral motion must begin from the pulp and not the base of the finger. In summary, the hand reaches equilibrium when there is harmony between its intrinsic and extrinsic muscles.

The index finger is stable if it is inclined from the radial side. If it is turned on the ulnar side, this destabilizes the hand. The middle finger is, meanwhile, a finger that moves laterally and is extremely stable. It can serve as a stabiliser for the other fingers. The ring is the true functional axis of the hand, and everything can be organized around it. It is difficult to move up, but if we use the sequential winding of the phalanx, it facilitates the extension. The auricular has its own musculature. It is sometimes difficult to control because of this characteristic.

© Jean-François Desrosby D.Mus. 2015

Left hand

The main problem related to the left hand when playing guitar is maintaining the arm in the air, often for many hours. In order to let the hand be entirely free, it is important to remember that each muscle must play the role for which it was designed. First, it is necessary to ensure that the shoulder blade is in place (in coaptation) using the technique mentioned above. To maintain the arms in the air, all the muscles of the shoulder must be involved. The arm must be held in the air, even if the instrument is not there. This seems obvious, but after several minutes of instrumental practice, those tired muscles relax, and the hand tends to hang onto the neck of the instrument and thus sustain the weight of the arm. The hand then loses a lot of agility. In addition, the small hand muscles are required to perform a function against nature. This causes unusual tiredness and multiplies the risk of injury. This is a problem that we find regularly among guitarists led by the good intention of playing relaxed. In attempting to relax the muscles above the shoulders, they place the weight of the arm on the hand.

Another issue related to the left hand is that it must be maintained in supination. I’m talking about the hand to draw your attention, because here (as in the case of the elevation of the arm), the hand is far from being the origin of the movement. If that is the case for you, learn to change your conception of things. It can be difficult to stop considering our precious hands to be the centre of the universe. As the Buddhist proverb says, “A finger points to the moon; unhappy are those who look at the finger.”

Thus, the supination of the left arm must take root in the shoulder. The rotation is done from the glenohumeral joint, which (surprise!) allows one to perform the supination of the arm from the base of the shoulder. This arm is held in place by the strong bicep muscle. Under no circumstances should the movement of supination be done through the action of muscles in the forearm. Moreover, the hand must never be the source of the movement. One must, under all circumstances, use the small radial and ulnar muscles to turn that hand and, by extension, the rest of the arm. They are not strong enough to fight against other muscles located upstream, which themselves were not involved in the road to supination. They would find themselves antagonists of the biceps, and that would harm them and cause them injury. Imagine how much the utilisation of the radial and ulnar muscles in the action of supination influences the freedom of movement of the hand. It finds itself in a state of constant contraction and effort, which inhibits the action of the fingers in the realisation of the precision work for which they were actually designed.

The forearm is mainly used to place the hand in an optimal way by extending the movement of the shoulder and biceps. It completes the positioning accuracy, because thinner muscles act with greater precision. Nevertheless, the forearm should be the engine of the full supination of the left arm.

On the topic of the optimal placement of the hand, let’s now, without going into detail, take a look at another basic principle. When the wrist is slightly inclined from the radial side (thumb), it facilitates the action of the index and middle fingers. These two fingers gain accuracy and stability when they are placed as well. However, this position is a bit more demanding on the tendons; thus, it should not be the basis of our positioning. If, on the contrary, we impose a slight flexion at the wrist on the ulnar side (little finger), the fingers will be freer and faster. Note that the change is evident especially in the auricular and ring fingers, but the middle and index fingers also gain agility. Unfortunately, they lose stability. It is also important to reinforce the elbows and shoulders in the lateral flexion of the wrist so you do not overload the muscles of the upper extremities.

The next concept to be referred to is that which Chamagne1 named in his various writings the principle of extended opposition. This concept is characterised by the ability of the thumb to oppose the other fingers. It is also important to know that the metacarpals corresponding to the last two fingers are mobile, unlike those corresponding to the index and middle fingers, which are fixed.

These movable metacarpals allow greater adaptability of the hand, whose primary function is grasping.

The principle of extended opposition is simple. When the thumb moves away from the index finger, it contracts the first dorsal interosseous and the two beams. With this contraction, the first dorsal interosseous ligament pulls on the deep transverse intermetacarpal, which has the immediate effect of solidifying the arch of the hand by blocking the metacarpal corresponding to the last two fingers.

In this way, the hand is stable, and it is easy to control the fingers in a highly precise way. The brain, which has the clear purpose of orienting itself in space, can direct the fingers in that same space with acuity increased tenfold.

It is also fundamental to find the right level of pressure of the fingers on the string. We often think that significant pressure is required to produce a sound that is clear and pure. I propose the following exercise to be aware of the weight required to produce a beautiful sound. Gently press the index finger of your left hand on the first string at the first fret. While playing the string lightly with your right hand, slowly increase the pressure on the string. As soon as you get the pure and clean sound you want, note the amount of pressure you are exerting. You have discovered the optimum pressure. 

It is essential to understand how too much finger pressure on the neck can affect the hand: This can lead to the extreme stress of the pulleys that pass through the tendons of the fingers, which then creates a virtual brake. The speed of the fingers is therefore greatly reduced.

1Philippe Chamagne is a kinesiologist specialising in disorders related to the practice of musical instruments. He is an author and speaker and the founder and technical advisor of the Musician’s Clinic in Paris.

© Jean-François Desrosby 2015

Blades of steel!


If there were only one piece of advice to be garnered from everything that I address in my research, this would surely be that relating to the separation of the shoulder blade. This is actually the most common issues among musicians. By relaxing the shoulder muscles, we cause a structural problem in the shoulder blade region. The latter becomes prominent. If you pass your hand over the shoulder blade, and you can actually feel the tip of it, this means that your are are afflicted by this terrible “evil” that I call the “sharp blade”!

Like many nerves, muscles and tendons that cross at the shoulder blade, it is essential that it be maintained in its proper place (coaptation) to ensure optimal movement of all members driven by the structural elements crossing at this place. The effect of a well-positonned blade can be felt by the fingertips. To maintain the blade in place, it is essential to ensure the tone of some of the upper back muscles. This is achieved by extending the shoulders (and the collarbone) slightly and adding this a slight forward motion. It goes without saying that the shoulders must be extremely toned, and under no circumstances should one release the muscles below this region.

I am aware that it is difficult to visualize without example, but I am working on something that will help you better understand these concepts. Stay tuned!

 © Jean-François Desrosby (D.Mus.)

Posture and self-confidence

We already know that posture plays a significant role in optimizing our movements when playing an instrument. Many of you may be surprised to know that posture also affects self-confidence.

If we can guess the level of self-confidence of someone by analyzing his posture, it is as well true that our own posture reflects our confidence in ourselves.

So if our posture reflects our confidence, can we influence our level of confidence intentionally by changing our posture? The answer is yes. Good posture will affect your level of personal confidence in addition of giving others the image of someone more confident about his abilities. If we add those benefits to both the injury prevention and optimizing technique, there is no reason for you not to work to improve your posture, and this, in your instrumental practice as in your daily life!

© Jean-François Desrosby (D.Mus.)