6 Ways that Muscles Misbehave

Tuesday Oct. 25th, 2022


The following is adapted from Ending Pain.


Most of us don’t understand pain, but we all experience it. The Western medical system generally sees pain as a sign of something broken that needs fixing—as a manifestation of injury or disease, an inevitable consequence of damaged tissues. This pathology model of pain is both thoroughly inculcated into popular thinking and, unfortunately, wrong in most cases. 

Actually, most pain can be traced to hidden sources of muscular disturbance known as “myofascial trigger points.” Briefly, trigger points in muscles generate “danger signals” that are sent to the central nervous system, which evaluates the signals to assess the threat level. Based on that assessment, the brain may choose to “output” what we know and feel as pain. 

When muscles develop trigger points, they can misbehave in a variety of uncomfortable, painful, and disruptive ways. Unless practitioners understand that these patterns of dysfunction are commonly caused by trigger points rather than injury or disease, they are likely to pursue inappropriate treatments that make the situation worse. 

Here are six common ways muscles misbehave, which are often misdiagnosed. 

1. Strength Deficits
Many patients come to our clinic having been assessed by a physical therapist or other medical professionals as having a “strength deficit.” In these cases, the patient has failed a strength machine evaluation, and the doctor will assign them strengthening exercises for whichever muscles tested weak. But often, these muscles aren’t truly weak at all; they have developed trigger points that lead to dysfunction.

Once a muscle becomes overloaded and develops trigger points, some percentage of its fibers are essentially taken offline and locked in a contracture; they become taut fibers. When a motor signal is sent to the muscle, many of its fibers cannot respond because they are already contracted. 

These taut fibers send danger signals to the spinal cord, which can cause active pain referral. As a result, when the patient tries to engage the muscle, they are likely to feel pain as the muscle bunches up. In addition, once the CNS receives those danger signals during a muscular contraction, it can inhibit that muscle and engage its antagonist as a way to provide safety. 

Before we can ask the muscle to take on more work, we have to help the muscle fibers become healthy. Otherwise, if you put additional demands with resistance training on muscles that have trigger points, that’s a formula for more overload, and they are likely to get worse. This happens often and is a primary cause of failed therapy. 

2. Resistance to Stretch
Another sign that trigger points are present in a muscle or muscular system is limited or compromised range of motion in the corresponding joint or joints. This phenomenon is often present in so-called frozen shoulder syndrome.

Resistance to stretch is an easy phenomenon to reproduce in a muscle with trigger points. As the muscle lengthens, the taut fibers attempt to lengthen as well, pulling apart the area of the sarcomeres in contracture. This mechanical disturbance of the trigger point will tend to irritate the contracted tissues, increasing their signaling to the spinal cord. Discomfort will increase, and the patient may notice pain in the stretching fibers as well as the referral zone of the muscle. 

As soon as there is a pain response, the CNS tends to go into protective mode by locking things down with muscular engagement. For the CNS, reduced motion equals increased stability and safety, and taut fibers from trigger points are a useful way to provide additional stability without excessive energy demands.

Stretching a muscle with trigger points is a reliable way to produce its pain referral pattern and assess which muscles are responsible for a pain pattern. It is not, however, a good first step in treatment. In cases where range of motion is limited and the muscles are resistant to stretch, it’s a mistake to try to lengthen muscles before therapeutic and rehabilitative work on the tissues. 

3. Grabbing, Shaking, Twitching
If trigger points are present in the muscle or its antagonist, you may notice that the muscle periodically “grabs,” resisting lengthening or shortening. You must move the joint slowly, paying close attention, or you might miss it. You might also notice a muscle twitching at rest or feeling shaky and unstable when the client attempts to engage it. This is a strong sign that taut fibers are sending disturbing signals to the spinal cord, confusing the system about how to respond.

Muscle spasms may accompany trigger point dysfunction. Some muscles spasm when you try to shorten their fibers if they have embedded taut fibers. You may have experienced this phenomenon in the form of a charley horse in the hamstrings or calves. Once the spasm starts, you basically have to wait until it subsides. They aren’t necessarily painful, but they compromise the muscle’s ability to both lengthen and shorten. 

4. Poor Balance and Coordination
Poor balance might also be an indicator that trigger points have developed in the body. Good balance, as in standing on one foot, requires a constant, fluid interplay between muscles on both sides of a joint. Balance poses such as tree pose in yoga aren’t static experiences—the muscles controlling the ankle and foot must perform continual micro-corrections to maintain stability. If these movements become too large, the person will wobble and shake.

Trigger points can negatively affect one’s balance and coordination by sending erroneous signals to the CNS regarding muscle tension and length. This process can disturb the coordination between agonist and antagonist muscles, resulting in poor balance. Related signs include dropping things, poor fine motor control reduced ability to play musical instruments, poor performance in sports, and similar problems.

5. Muscle Inhibition
The manual therapy field has a concept called muscle inhibition that is based on the observation that muscles sometimes don’t engage when or as fully as they should. It can also describe a situation when muscles that should contract simultaneously fire in succession, causing imbalance in the joints and even in the position of bones. 

To better understand this phenomenon, let’s look at a prime example. A muscle that commonly becomes inhibited is vastus medialis, the medial short quadricep head. The quadriceps have oblique attachments to the tendon that controls the kneecap. The branch on the outside of the leg (vastus lateralis) is a larger, more powerful muscle than the inside quadricep (vastus medialis). When a patient develops pain and swelling around the knee, it is common to observe that the vastus medialis doesn’t contract right away as the patient tries to extend their knee, causing the patella to divert in a lateral direction. This is sometimes called inhibition of the vastus medialis. 

In the case of an inhibited vastus medialis, the patient will likely feel pain around their knee, but the root cause is often trigger points in other, more distant muscles. In some cases the body seems to let one side of a functional antagonist relationship dominate when dysfunction develops.

6. Shortening Dysfunction and How It Blocks Stretch
Healthy muscles can be stretched or shortened without causing pain or other discomfort. Most people are familiar with stretching and know that certain muscles will feel uncomfortable if you attempt to stretch them beyond a certain point. Very few people realize that muscles can become dysfunctional when shortened. In fact, shortening dysfunction is an even more significant issue than stretching dysfunction and can occur with either passive or active shortening.

Active shortening occurs when you engage a muscle. If you use your biceps and brachialis to bend your elbow, those muscles are contracting actively and the overall length of the fibers becomes shorter than they were with the elbow straight. If you rest your arm in a bent position, such as during sleep, you are no longer actively contracting those muscles. At that point, we say that biceps and brachialis are being passively shortened.

Normally, muscles become softer when in passive shortening, so a telltale sign of shortening dysfunction is the muscle hardening as it is shortened. This indicates that a type of automatic spasm or contraction is happening within the muscle without a motor signal from the spine telling the fibers to engage. This condition can sometimes be painful, and even if not, it can stop the joint from bending any further, meaning that it inhibits the stretch of the muscle’s antagonists.

It Doesn’t Have to Be This Way
When muscles develop trigger points, they can misbehave in a variety of ways that confuse medical practitioners, who assume an injury at the site of the pain. Often, trigger points can masquerade as more serious conditions, leading physicians to misdiagnose the source of the pain. 

When I became a bodyworker, I began to realize that pain is almost universal. Most of my clients were seeking relief for their chronic or acute pain, having been failed or dismissed by medical doctors and other professionals.

It doesn’t have to be this way. The proper treatment of trigger points offers an effective solution to common muscle misbehavior.

For more advice on muscle behavior, you can find Ending Pain on Amazon.

Chuck Duff is a Renaissance man who loves challenging the status quo. He studied Buddhism and psychology at University of Chicago, then moved to a career in software research and innovation. He is a serious guitarist and a trained chef. His daughter is a talented dancer and photographer. His own back pain led him to research pain science and develop CTB, a novel integration of Thai bodywork and trigger point therapy. He taught at Pacific College of Oriental Medicine and founded the Coaching The Body Institute in 2001. He remains pain free by practicing what he preaches. More at coachingthebody.com.