Part I: Trigger Points - What are these “Knots” in My Muscles?
If you have ever received body work, soft tissue treatment, or a massage, you’ve probably heard the term “trigger point” or “a knot in the muscle”.
A trigger point is considered a small area of muscle cells that are contracting more at rest compared to the rest of the muscle. This is thought to be caused by an increase in the activity of stretch receptors in our muscles, which causes protective muscle contractions.
Although this is commonly found in those who are either inactive or those who are too active (& don’t understand recovery), this is not normal for the muscle and it causes the muscle to behave poorly (weaker &/or tighter).
This small area of the muscle that is contracting at rest, a 'trigger point,' is usually very sensitive to pressure or touch and is sometimes described as a burning or aching sensation when compressed. A trigger point often increases resting tension throughout the entire muscle, leading to excessive tension at the tendon of the muscle and thus at the attachment point on the bone.
These trigger points experience something called ischemia, which means they’re not getting enough blood flow and oxygen.
As an example, squeeze your fist firmly for a few seconds, then open it and see how white your palm is. You should see the palm turn pink again within seconds. Your hand in this example is behaving like a trigger point. Muscles that are constantly contracting at rest constrict blood vessels and are therefore depriving the muscle of oxygen.
The lack of blood & oxygen changes the biochemistry of the muscle and creates an acidic environment in the muscle tissue. This causes nerve sensors that pick up on chemical changes in the tissue to send a bunch of electrical impulses to the brain.
Remember, because of the trigger point, there is more resting tension in the muscle now, so nerve sensors that pick up on changes in our muscles' mechanical tension will also start to send electrical impulses to the brain.
When the brain gets a lot of signals from these different mechanical & chemical sensors, the brain produces uncomfortable and annoying sensations. These sensations can be felt as aches, pains, or even similar to the feeling of your 'foot falling asleep'. The brain will create these sensations to get your attention to move or do something about these changes going on in the muscle.
Trigger points can cause local pain or sometimes they can be felt in another area of the body, which is called referred pain.
These are some of the reasons why trigger points are very sensitive to compression, can make a muscle weak and easy to fatigue.
What Causes These Annoying Trigger Points?
Trigger points are typically caused by:
1. Injury or trauma - like muscle strains &/or contusions.
2. Too much or too little physical activity or too much of the same repetitive activity.
3. Inappropriate motor control or stabilization.
Why Does Our Body Tighten Up? goes into this in relation to motor control as well.
With respect to injury, for example, with mild muscle strains or contusions, the muscle will go into a reflex protective contraction, also known as guarding - this is an abnormal muscle behavior. This causes short term protection by providing you with an 'internal splint,' but can interfere with healing as it overloads the muscle-tendon with excessive tension & can impair circulation as discussed earlier.
The second and third causes tend to go hand in hand. As illustrated in the "U" shaped diagram, trigger points or muscle imbalances are associated with both too much activity or too little activity. Either end of the spectrum, without a balance of training, Active Recovery strategies, and planned days off, can develop trigger points leading to movement imbalances.
The current thought process is because of inappropriate stabilization or altered motor control. Simply put, the muscles that are responsible for stabilizing your shoulders, hips, pelvis, and spine aren't working for you. In this situation, the brain has to figure out a plan B for proper stability. The easiest way to do that is to increase resting muscle tension in the muscles that were more designed to move and propel us (prime movers) like our pectorals, traps, calves, quads, hamstrings, hip flexors, and back muscles. Aren't these the muscle groups where trigger points like to hang out? In Why Does Our Body Tighten Up? I also discuss how this distorts proprioception or our awareness of our own body's position in space.
This all leads to the overuse of our prime mover muscles & under use of our stabilizers. We typically complain about the muscles that are working over time, asking people to rub them, "release" them, and stick needles in them, while the stabilizers continue to be lazy under the radar.
In "Why Does Our Body Tighten Up?" and "Why Does Controlled Mobility Matter?" I go into a more detail about the importance of mobility in our joints and muscles as it relates to how the brain controls movement.
So after getting a solid massage or receiving trigger point therapy, the muscle that the trigger point was living in often feels looser, better, and you’ll feel like you have more range of motion.
But if you don’t teach & train your muscles how to control the new ranges of motion that was achieved from the hands-on work and train the stabilizers of your hips, pelvis and spine, the trigger points will keep coming back. They will keep coming back because there is no other option for stability. Through training we have to convince the brain that we no longer need this excess resting tension anymore, because we have control.
Learning how to control & use our bodys' available ranges of motion is the essence of preventative musculoskeletal practice.
In Part II we discuss "How do we know if a trigger point is relevant?"