Ferraris and Eccentric Control

Greeting Miss S. and her mom in my waiting room, I could see the worried looks on their faces. 

"My daughter is very serious about her music," the mom began. "She works very hard at it, and we are worried that this could be a real problem going forward." 

"What instrument do you play?" I asked. 

Miss S.'s face immediately took on a look somewhere between pride and embarrassment. 

"Four instruments, actually," she said. "The piano, string bass, guitar, and baritone horn." 

"Let me guess. Is the problem in your left hand?" I inquired. 

"It is," replied Miss S. with a little surprise in her voice. 

"Am I correct in remembering that the baritone horn is held with the left hand and the valves are played with the right?" 

"Yes, that's correct," Miss S. answered. "The pain I feel in my arm and hand started after a long session of playing the baritone. My school band played in the Fourth of July parade, which was unusually long this year. The pain started the next day." 

"Show me where you hurt," I instructed. Miss S. pointed to the flexor digitorum muscles on her left forearm. 

"It is a deep ache and when it starts, I cannot continue playing." 

"Did you notice any pain before the parade episode?" I asked. 

"Not really," she answered. "One thing I did notice is that I haven't been able to do trills and more intricate passages the last few weeks. It seemed like the more I practiced them, the worse I got. I also don't understand why it now hurts on this side of the arm," she said, pointing to the extensors. "When I press down on the keys or strings, doesn't it involve the muscles on this side (pointing to the flexor muscles) of the arm?" 

"Correct, but it is a little more complicated than that," I replied. "Put your hand over my extensor muscles and feel what happens when I contract my finger flexors, like playing the guitar. Do you feel all that movement?" 

"Wow, that's more movement than I thought," Miss S. said. "How come?" 

"Two reasons," I replied. "First, every push with your finger requires these extensor muscles to lift the finger upward to repeat the motion. That's the simple part. Second, and much more complicated, the extensor muscles control the descent of your finger to its intended target. When you press down the strings on the bass or guitar, do you always attack them with equal intensity?" 

"No, varying the pressure is how you get the differences in tone," she said.

"Exactly," I concurred. "Nuances of pressure are made possible by the control of the extensor muscles, more than varying the power of contraction of the flexors."

Whenever I think about this concept, I think of a chance meeting I had with someone who was parking his new Ferrari. I was totally awed by this amazing vehicle, especially since I had never actually seen one. Seeing my fixed stare at the imposing engine in the back of the car, he looked at me and declared that the engine is not the most impressive feature of the car. As I scanned the car with my eyes, I couldn't stop looking at the engine. Smiling patiently, he kept saying over and over that the engine isn't the most impressive feature. I knew he was guiding me to something, but I could not imagine what. After what seemed like an eternity, it hit me: it had to be the brakes. The owner smiled and pointed out that making a car go really fast isn't terribly difficult, but stopping a car moving that fast requires an amazing feat of engineering. 

"The same principle is true in the body. When one muscle contracts to make an action happen, the opposite muscle must control the quality and speed of that action. Like the big engine, the muscles creating the action get all the attention. The unsung heroes are the muscles controlling the action. In physiology, that function is called eccentric contraction, and it is one of the hardest jobs a muscle can do." 

"Is that why I had a hard time doing trills?" Miss S. asked. "Was that an indication of when this problem began?" 

"Great insight," I exclaimed. "It was probably the first sign of muscle fatigue and potential injury. Many of my athletes also notice little control failures before there is ever an obvious sign of pain. The more you learn to pay attention to smaller cues, the more likely you are to prevent more serious problems. Athletes and musicians both discover that the body is their real instrument and massage therapy is a great way to further that self-discovery process." 

"I never really thought of my music practice as athletics. Can you get me out of P.E. on Monday?"