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The Movements of the Bow Arm

Is it weight, leverage, or pressure?  The physics explained and mystery acknowledged.

By Jamie Fiste, Professor of Cello at Central Michigan University
Most of the 'high art' of string playing happens in the bow arm. Because of this, the bow arm is often the biggest source of difficulty. There are also many misconceptions surrounding the bow arm and hand that may get in the way of making progress. 

This article looks at some fundamental questions regarding bow arm technique that relate to tone production.  Let's get started...

Two Different Challenges 

Regarding bow technique, one needs to keep in mind that playing at the tip of the bow poses an entirely different set of challenges to playing at the frog. Consider these two main differences:

Playing at the Frog: Arm and hand are close to point of contact on the string

Playing at Tip: Arm and hand are far away from point of contact on the string

These differences will be the primary guide as we think through bow arm technique.

Arm Weight: A Common Misconception?

What I am about to discuss is a hotly debated topic among string players, so let me 'weigh' in on this. Because string players are eager to avoid the idea of "pressing" the bow into the string, generally the idea of "weight" is preferred over the term "pressure". I often use the word "weight" myself when referring to the transfer of power of the arm through the bow into the string. There is a conundrum here, however, because unless we are talking about putting the frog of the bow on the string, arm weight just doesn't seem possible. In fact, Paul Rolland, one of the string pedagogues I look up to the most, wrote an article called Bow Pressure in which he argues that arm weight is not possible. So why then do I reference the power transfer as "weight"? Simply this; because it feels like weight and the sensation is often more important to me than the physics. But back to the idea that weight is not actually possible when speaking of the bow arm.

Let's start with this thought experiment. Imagine placing the bow on the string at the tip. Now imagine placing something heavy at the frog. What happens? Well, obviously, the bow falls to the ground. You see, merely placing weight at the frog will not do a thing to transfer that weight through the stick. What is also needed is a counter force upwards to create a lever. If you think back to junior high, they taught us that this counter force is the fulcrum and it's the thumb that acts this role in the bow hand. And since our thumbs are attached to our arms it's difficult to imagine how our arms could be applying weight when the thumb is exerting an upward force.

I've thought about this a lot. Perhaps, I have reasoned, that a part of our arm through the thumb exerts an upward force while another part of our arm can apply gravity or weight. I admit this may be a possibility but I severely doubt that enough weight could be applied this way.  The thumb originates on the same side of the hand that applies a downward force into the string.  I cannot see how weight could be applied into the stick through the same side of the hand as the thumb exerting an upward force.

Many will say at this point that power into the string is better thought of as leverage rather than weight. The mere presence of a fulcrum by definition implies a lever and a lever implies leverage - so the point goes. But this really doesn't solve the issue of weight because weight can be a part of a lever - it just needs to be on the correct side of the fulcrum. The problem is our thumb; it must provide an upward force that just seems to negate the possibility that the primary application of power is through the weight of the arm.  So I wouldn't pose leverage and weight as incompatible. I would just say the bow arm acts as a lever largely apart from weight.

OK then, what about playing at the lower half of the bow, isn't weight a possibility there? Again, let's go back to our thought experiment. Let's place the bow 2 inches from the frog on the D string and imagine putting a weight on the frog of the bow. What happens? Again, the bow teeters off the string onto the floor. You literally have to place the frog directly on the string to prevent the bow from falling to the ground. And we haven't even brought up the C string, which necessitates a sideways application of power, making the application of weight impossible by resting an object on the string - it will simply fall off due to gravity (gravity only goes in one direction after all!).

The Application of Leverage at the Frog and Tip

So let's just put aside the question of arm weight for a moment and accept that leverage is at play when it comes to the bow arm. Why does it feel so much easier to apply leverage at the frog than at the tip? The answer: less stick. Less power is lost in the stick at the frog than at the tip where the power must travel through many times more wood (or carbon fiber). This being the case, more leverage is needed at the tip than the frog for the same amount of sound. To use the words of Rudolf Matz, we need a physiological crescendo during the course of a down bow to keep the same level of sound and a physiological decrescendo during the course of an up bow to maintain the same sound. 

All of this needs to be kept in mind as we develop our bow technique. 

The Physiological Crescendo and Diminuendo

So the first question before us, as we seek to apply this information, is whether or not there is a motion in the bow arm that will aid us in physiological crescendos and diminuendos. I believe there is: the pendulum effect.  In other words, a pendulum swing from the shoulder can assist greatly in feeling these physiological effects. As we pull a down bow, a gradual rise of the elbow will allow for an increase of leverage into the stick. If you doubt me on this, just try applying leverage at the tip with the elbow nice and low.  Now try it with the elbow at the same height as the string. Which has less leverage? Which has more? You see what I am getting at here. Similarly, during the course of an up bow from the tip to the frog, the elbow can gradually fall (here is where gravity can help), allowing quite naturally for a physiological diminuendo. 

To summarize, this physiological crescendo and diminuendo necessary in bow technique gets mirrored in the rise and fall of the elbow (upper arm) pendulating from the shoulder. Once you get used to it, you will be hooked!  But this isn't the only benefit.

Avoiding a Protracted Scapula

In my teaching over the past 30+ years, I have seen a number of things, many of which repeat over and over. And one of these recurring phenomena is not using enough of the lower half of the bow. It's as if the student's arm "hit a wall" and can't proceed comfortably any further in their journey to the lower half. 

The main culprit is a failure to allow the elbow to gradually drop during the up bow. You see, if the elbow does not drop, the arm will necessarily swing forward, protracting the scapula (the fancy way of saying the shoulder blade comes forward), creating a bunch of tension in the shoulder and upper back. When the tension reaches a certain point, the up bow just stops.

When you lower your elbow, it allows your arm to drop more to your side with far less protraction of the scapula, if any at all, depending on the length of your arm. Not to mention, gravity will help your up bow to the frog just like gravity brings a swing back down to it's lowest position. Give it a try to see what I mean.

Arcs and Circles

This swinging of the arm is a very natural motion owing to the hinge of the shoulder joint. Have you ever noticed how virtually everything that moves in nature does so in either an arc or a circle?  And nature is incredibly efficient. Here are just a few examples in no particular order: weather patterns, ocean currents, waves, water down the drain, a vibrating string (strings vibrate in a circle), solar systems, and galaxies. Objects will move in straight lines only if no other force is acting upon them. In the case of the arm, the force acting upon it while moving back and forth is the shoulder joint and gravity. Whether you drop your elbow or not during the up bow, an arc is going to happen; the arc is either going outwards, protracting your shoulder blade, or down towards your side.

And you know which arc I prefer!

The Mystery of it All  

To conclude, let's bring it back to weight once again. I mentioned I often use the term "weight" when describing the application of power through the arm and into the stick and string. And here is the mystery of the bow arm; it feels like weight.  In my own bow arm and hand, if feels as if the entire weight of my arm is being transferred through the front of my bow hand into the stick. But, of course, this is impossible. Nonetheless, the sensation has a distinct feeling of weight to me. And the sensation is often more important to me as a teacher and player than any other factor. 

Why does it feel so much like weight? I don't know.

I'm ok with a little mystery in life. It keeps things interesting! 

That's my story and I'm "sticking" to it! Get it! "Sticking", the bow? Happy bowing!


Authored by Jamie Fiste, Professor of Cello at Central Michigan University.
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