The term “neuromuscular” refers to the interconnected relationship of the muscular (biomechanical) and nervous (neurodynamic) systems. It involves the interplay of the nerves and muscles to produce movement that is precise. Dysfunction in the neuromuscular system can be manifest as poor timing of muscle contraction, under- or over-recruitment of muscle fibers, and even central nervous system inhibition of a muscle or group of muscles.
Vladimir Janda proposed that our neuromuscular systems can be broken down into two subcategories: tonic and phasic. Tonic muscles are those that are prone to tightness and increased activity, whereas phasic muscle are prone to over-elongation and decreased activity. Our tonic muscles are more primitive and form earlier in our development than the more precise phasic muscles. Take a look at how a newborn infant is positioned and which muscles she is able to use; these are the same muscles that we tend to use when our systems are threatened. We tend to “carry stress” in these muscles as well, which we can see in tight upper trapezius or low back extensor muscles.
Our neuromuscular systems can be affected by threats that are not exactly physiological and sometimes even psychological in nature resulting in a physiological response. Let’s say that you are happily eating your lunch when all of a sudden a hungry lion jumps out of the bushes threatening to eat you. Your sympathetic (“Fight or Flight”) nervous system turns on, and you immediately drop your sandwich prepared to either fight off the crazed lion or run away from it. Because the two are intertwined, the increased activity of your sympathetic nervous system increases the likelihood that you will use your tonic muscles to fight or flee. Although we are rarely confronted with the threat of man-eating lions, we all tend to face sympathetic-inducing threats on a daily basis including things like financial, relationship, and job-related issues or hardships.