Knotted Up: What Really Happens Inside a Muscle Trigger Point

A woman in a red sleeveless top is performing a massage on a man lying on a massage table. The man is shirtless, revealing tattoos on his torso, and is wearing black shorts. The setting appears to be a fitness or training facility, with wooden boxes and fitness equipment in the background. The woman is focused on her task, using her hands to apply pressure to the man's side.

Muscle knots are one of the most common complaints among active people, office workers, and anyone under stress. You might feel them as small lumps under the skin, tight bands that limit movement, or tender spots that radiate pain. These knots are more than random tension. They are called myofascial trigger points, and they have a well-defined biology that combines local muscle contraction, chemical irritation, and nervous system involvement.

Understanding what makes up a trigger point helps you demystify chronic pain and take more effective steps to release it. This series will break down exactly what happens when a muscle gets stuck, why it stays contracted, and what you can do to address it without relying on gimmicks.

Defining a Trigger Point

A trigger point is a localized area of hyperirritability within a muscle or fascia. It is not the same as a general muscle spasm, which involves the entire muscle contracting. Instead, a trigger point is a small cluster of muscle fibers locked in a sustained contraction, surrounded by tissue that may be normal or only mildly tense (1).

Key features of a trigger point include:

A palpable nodule within a taut band of muscle
Local tenderness when pressed
Referred pain in predictable patterns
Restricted range of motion

Trigger points can be active or latent:

Active trigger points cause pain spontaneously or when you move.
Latent trigger points only hurt when pressed but still limit flexibility and muscle function (2).

In clinical settings, practitioners locate trigger points by feeling for taut bands and testing the area’s sensitivity. You can often find them yourself by pressing into areas of muscle tightness and noting whether you feel tenderness or referred discomfort.

💡 Key Takeaway: A trigger point is a small area of muscle locked in contraction that causes tenderness, restricts movement, and sometimes refers pain elsewhere.

The Taut Band Phenomenon

The concept of the taut band is one of the defining elements of trigger point physiology. Under healthy conditions, muscle fibers contract and relax evenly. In a trigger point, a subset of fibers stays shortened while neighboring fibers remain at normal length. This creates a rope-like band you can feel through the skin (3).

What causes this?

When a muscle is overloaded or injured, certain motor units (the combination of a motor neuron and the muscle fibers it innervates) can become hyperactive. The motor endplates start releasing excessive amounts of acetylcholine, the neurotransmitter that triggers muscle contraction (4).

This leads to:

Sustained contraction of localized fibers
Compression of nearby blood vessels
Reduced oxygen delivery
Accumulation of metabolic waste

This process is sometimes called an energy crisis, because the contraction blocks the circulation needed to relax the fibers. Without adequate ATP, the muscle cannot reset to a resting length.

❖ Quick Reference: How a Taut Band Forms
Excessive acetylcholine release
Local contraction of muscle fibers
Compression of capillaries
Oxygen deficit
Accumulation of waste products
Ongoing contraction

This creates a self-sustaining loop. Even when you are resting, the knot persists because circulation and metabolism cannot reset the area effectively.

💡 Key Takeaway: A taut band is formed when a small group of muscle fibers becomes locked in contraction due to excessive neurotransmitter release and an energy crisis that prevents relaxation.

The Chemical Soup of Pain

A trigger point is not just a tight muscle. It is a small biochemical factory producing a concentrated mix of substances that irritate nerves and sustain pain. This “chemical soup” is why pressing on a knot often feels more intense than pressing on ordinary tightness.

Key chemicals found in trigger points include:

Substance P
A neuropeptide that sensitizes pain receptors, making the area more tender (5).
Bradykinin
A peptide that promotes inflammation and increases sensitivity of nerve endings (5).
Calcitonin Gene-Related Peptide (CGRP)
Contributes to swelling and amplifies pain signals sent to the brain (6).
Prostaglandins
Lipid compounds that sustain inflammation and heighten the perception of discomfort (6).
Serotonin
While often linked to mood, serotonin in muscle tissue can act as an irritant and make trigger points more sensitive (7).

How do these chemicals accumulate?

When circulation is restricted due to sustained contraction, the muscle cannot clear out waste products. Over time, this creates an acidic environment and keeps the nerve endings in a state of irritation.

❖ Quick Look: The Pain Loop
Sustained contraction restricts circulation.
Waste products and inflammatory chemicals build up.
Nerve endings become hypersensitive.
Pressure or movement triggers pain.
The muscle contracts further in response.

This explains why some knots feel sore even without touch, while others only hurt when pressed. The chemical environment determines how reactive the trigger point is.

💡 Key Takeaway: Trigger points maintain pain through a mix of inflammatory chemicals that sensitize nerves and make the area tender.

Referred Pain Patterns

One of the most distinctive features of trigger points is their tendency to refer pain away from the actual site of irritation. This can make diagnosis confusing, because you feel discomfort in an area that appears otherwise normal.

For example:

A trigger point in the upper trapezius can produce headaches around the temple and behind the eye (8).
A knot in the gluteus minimus can send pain down the side of the leg, mimicking sciatica.
Trigger points in the infraspinatus can create aching in the front of the shoulder and down the arm.

Why does referred pain happen?

Researchers believe it is due to convergence of nerve signals in the spinal cord. When sensory neurons from different areas converge on the same spinal segment, your brain can misinterpret where the signal is coming from (8).

Key characteristics of referred pain

Predictable patterns based on muscle location
Often described as dull, aching, or deep
Can be provoked by pressing on the trigger point

Examples of Common Referred Pain Maps

Upper trapezius: side of the neck, temple, behind the eye
Levator scapulae: neck stiffness, upper shoulder blade
Piriformis: buttock pain, back of the thigh
Gluteus medius: sacrum, outer hip

If you suspect referred pain, pressing on the suspected trigger point can reproduce or intensify the sensation, helping confirm the source.

💡 Key Takeaway: Trigger points often send pain to other areas along predictable nerve pathways, which is why muscle knots can mimic other conditions.

The Role of the Nervous System

Trigger points are not purely mechanical problems. They involve the nervous system at every step. When a muscle fiber contracts, it does so because of signals from the motor nerve endings. In trigger points, the motor endplate releases excessive amounts of acetylcholine, the neurotransmitter responsible for contraction (9).

This excessive release creates:

Persistent contraction of a small area
Ongoing irritation of nearby sensory nerves
Amplified pain signals sent to the brain

Over time, the central nervous system becomes sensitized. This means that normal pressure or movement starts to feel painful, a process called central sensitization (7). In chronic cases, even gentle touch or light exercise can trigger exaggerated responses.

Key aspects of nervous system involvement:

Peripheral sensitization: local nerves become hyperreactive due to chemical irritation.
Central sensitization: the spinal cord and brain amplify incoming pain signals.
Autonomic responses: trigger points can cause sweating, goosebumps, or changes in skin temperature near the area (7).

This neural dimension explains why simply stretching or massaging the muscle sometimes does not fully resolve pain. It also shows why stress, sleep deprivation, and emotional tension can worsen trigger point symptoms by keeping the nervous system in a heightened state.

❖ Quick Tip: Signs of Central Sensitization
Pain out of proportion to pressure
Widespread tenderness beyond the trigger point
Fatigue and unrefreshing sleep
Symptoms that fluctuate with stress levels

💡 Key Takeaway: The nervous system plays a central role in trigger points, both by maintaining contraction locally and by amplifying pain sensitivity over time.

Microcirculation and the Energy Crisis

Trigger points create a localized reduction in blood flow, known as ischemia. Without sufficient circulation, the muscle cannot clear out waste products or deliver oxygen efficiently. This shortage of energy molecules (ATP) traps the muscle fibers in a contracted state (10).

What happens in the energy crisis:

The knot compresses tiny blood vessels (capillaries).
Oxygen delivery drops in the affected area.
Metabolic waste accumulates, including lactic acid and inflammatory chemicals.
Low pH and hypoxia perpetuate nerve irritation.
The muscle lacks ATP to release the contraction.

This process is why many trigger points feel stiff and sore even after rest. The tissue is literally starved of the fuel needed to reset itself.

Why does this matter for treatment?

Approaches like manual pressure and movement help by:

Compressing and then releasing the tissue to force fresh blood into the area
Flushing out metabolites
Restoring ATP levels so the muscle can relax

Heat therapy can also improve microcirculation and help break the cycle, especially when combined with gentle movement afterward.

❖ Practical Strategy: Restoring Circulation
To address microcirculation issues:
Use steady manual pressure (30–90 seconds) to compress the knot.
Follow with gentle stretching to encourage fresh blood flow.
Apply heat packs to the area before activity.
Incorporate regular movement to prevent stagnation.

💡 Key Takeaway: Trigger points maintain themselves through a cycle of poor circulation and energy depletion, which is why targeted pressure and movement help restore normal muscle function.

The Role of Stress and the Sympathetic Nervous System

Stress does not just live in your mind. It shows up in your muscles. When you are under chronic stress, your body shifts toward sympathetic nervous system dominance, also called the fight-or-flight state (11).

Effects of chronic sympathetic activation include:

Persistent low-level muscle tension
Reduced circulation to peripheral tissues
Elevated stress hormones like cortisol
Slower recovery from micro-injuries

This tension does not always resolve when the stressful event passes. For some people, the nervous system stays “switched on,” keeping muscles in a partially contracted state that feeds into the trigger point cycle.

How stress maintains trigger points:

Increases acetylcholine release at the neuromuscular junction
Heightens sensitivity of pain receptors
Contributes to shallow breathing and poor posture, further straining muscles

It is also common for stress-related muscle knots to cluster in areas of emotional expression and postural strain, such as the neck, shoulders, and upper back.

❖ Quick Tip: Stress and Muscle Pain
If you notice your symptoms worsen during deadlines, emotional upheaval, or poor sleep, stress is likely amplifying your trigger points.

💡 Key Takeaway: Chronic stress keeps muscles in a state of low-level contraction and increases pain sensitivity, making trigger points more likely to form and harder to resolve.

Differences Between Trigger Points and Other Conditions

Not all muscle pain comes from trigger points. Sometimes, symptoms can overlap with other conditions, which is why accurate assessment matters.

Common conditions confused with trigger points include:

Muscle Strains
Acute overstretching or tearing of muscle fibers, often accompanied by swelling and bruising (1).
Tendinopathy
Pain originating where tendons attach to bone, usually aggravated by repetitive motion.
Nerve Entrapment Syndromes
Such as carpal tunnel syndrome or sciatica, involving compression of peripheral nerves.
Myofascial Pain Syndrome
A chronic pain disorder defined by widespread trigger points and central sensitization.

How to distinguish trigger points:

They produce referred pain in consistent patterns.
The pain is usually dull, aching, or deep rather than burning or tingling.
Direct pressure often reproduces the characteristic pain.
Muscle function is limited in a way that improves with pressure release and stretching.

If symptoms include numbness, severe weakness, or sudden swelling, further evaluation by a qualified professional is essential.

❖ Quick Reference: Trigger Point vs. Nerve Pain
Trigger Point Nerve Entrapment
Dull, aching, pressure-sensitive Burning, tingling, numbness
Referred pain in predictable maps Follows nerve distribution
Improves with manual pressure Often worsens with compression

💡 Key Takeaway: Trigger points have unique characteristics that set them apart from nerve pain or muscle tears, but careful assessment is critical for accurate diagnosis.

Evidence-Based Approaches to Releasing Trigger Points

Trigger points are stubborn, but research has shown several strategies can effectively release them. The goal is to restore circulation, reduce nerve irritation, and help the muscle fibers return to a relaxed state.

Evidence-supported methods include:

1. Manual Pressure (Ischemic Compression)

Applying steady pressure for 30–90 seconds can help the knot “release.”
This forces out metabolic waste and allows fresh blood flow when pressure is removed (12).

2. Dry Needling

Involves inserting thin needles into the trigger point to disrupt contracted fibers and promote local healing (13).
Can produce a local twitch response that indicates the muscle is relaxing.

3. Myofascial Release

A combination of sustained pressure and gentle stretching of fascia surrounding the muscle.
Often performed by trained therapists.

4. Heat Therapy

Increases circulation and makes tissues more pliable before manual techniques.
Common tools include moist heat packs or warm baths.

5. Stretching and Movement

Gentle, pain-free stretching helps maintain improvements after pressure work.
Movement prevents the return of chronic contraction.

❖ Quick Tip: Home Release Sequence
Apply heat for 10 minutes.
Use a lacrosse ball or fingers to apply steady pressure.
Hold until tenderness decreases.
Slowly stretch the muscle.
Move through the full range of motion.

💡 Key Takeaway: Effective trigger point release combines pressure, heat, stretching, and consistent movement to restore normal muscle function.

FAQ

Q: Are muscle knots dangerous?

A: No, trigger points are not harmful in themselves, but they can cause persistent pain and limit mobility if untreated.

Q: How long does it take to release a trigger point?

A: Some knots release in one session, while chronic ones may need repeated work over weeks.

Q: Should I use ice or heat?

A: Heat is generally more helpful for chronic tightness, while ice can reduce acute inflammation after overuse.

Q: Can I prevent trigger points?

A: Regular movement, stress management, hydration, and balanced strength training can reduce the risk.

Q: When should I see a professional?

A: If you have severe pain, numbness, unexplained swelling, or symptoms that do not improve, consult a qualified healthcare provider.

✏︎ Bottom Line

While muscle knots often start with mechanical tension, factors like nutrition, hydration, and daily habits also play a role in how well your body recovers and adapts. Staying aware of what you eat and how consistently you support your health can make it easier to spot patterns that contribute to tension over time.

Use PlateauBreaker™ to track your nutrition. We recommend tracking your daily habits so you can see trends and make informed choices that support your overall well-being.

Bibliography

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Hong, C Z. “Pathophysiology of myofascial trigger point.” Journal of the Formosan Medical Association = Taiwan yi zhi vol. 95,2 (1996): 93-104. https://pubmed.ncbi.nlm.nih.gov/9064014/
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Shah, Jay P et al. “Myofascial Trigger Points Then and Now: A Historical and Scientific Perspective.” PM & R : the journal of injury, function, and rehabilitation vol. 7,7 (2015): 746-761. doi:10.1016/j.pmrj.2015.01.024. https://pmc.ncbi.nlm.nih.gov/articles/PMC4508225/
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Knotted Up: What Really Happens Inside a Muscle Trigger Point

Defining a Trigger Point

The Taut Band Phenomenon

The Chemical Soup of Pain