Glossary Term
Muscle Fiber Dysfunction
Muscle fiber dysfunction is a neuromyofascial phenomenon that results from excessive stress on a muscle fiber. It is characterized by increased tone, taut bands, palpable nodules, myalgia, and centralization. The causes of muscle fiber dysfunction include excessive stress, insufficient blood flow, metabolic crisis, muscle fiber changes, chemical changes, and nervous system adaptation.
Muscle Fiber Dysfunction: Muscle fiber dysfunction isa general term used to encompass all commonly noted changes resulting from excessive stress to a muscle fiber, and the clinically observable phenomenon that result from those changes.
- The term "muscle fiber dysfunction" has been chosen to describe this as a neuromyofascial phenomenon to separate the subject matter from information that may explain dysfunction originating from damage to a joint (e.g. arthritis), damage to a nerve (e.g. neuropraxia) or damage to fascia (e.g. fasciitis).
Observable Phenomena Associated with Muscle Fiber Dysfunction:
- Increased tone (over-activity)
- General increase in tissue density
- Resistance to stretch
- Changes in EMG activity
- Changes in muscle spindle activity (H-reflex)
- Twitch response
- Taut bands
- Palpable nodules
- Myalgia
- Pain upon deep palpation
- Latent trigger points (tender points)
- Active trigger points
- Referral pain
- Diffuse myofascial pain and allodynia
- Centralization
- Whiplash syndrome
- Chronic low back pain
- Fibromyalgia syndrome
Pathobiology of Muscle Fiber Dysfunction:
- Excessive Stress
- Acute tissue trauma
- Continuous low-load activity
- Postural dysfunction
- Eccentric contractions
- Insufficient blood flow
- Capillary restriction (especially during isometric contraction)
- Insufficient recovery (cycling of motor units is insufficient)
- Metabolic crisis
- Hypoxia
- cytochrome c oxidase deficiency
- Mitochondrial, sarcotubular system and cell membrane changes
- Moth-eaten fibers and degeneration
- Muscle fiber changes
- Taut bands and palpable nodules
- Type I fiber hypertrophy
- Increase in Type IIA fibers
- Increase in transitional fibers
- Preferential loss of Type I and/or Type II motor units
- Infiltration of adipose and/or connective tissue
- Chemical change
- Markers of inflammation and pain
- Acidity (pH)
- Excessive Ca2+
- Excessive acetylcholine (ACh)
- Nervous system adaptation
- Altered reflex sensitivity
- Dorsal horn reorganization
- Hippocampus inhibition
- Autonomic system involvement
- Centralization
For more information, please refer to our course and systematic review -
Muscle Fiber Dysfunction and Trigger Points
Comments
Synonyms
- Muscle fiber pain
- Muscle fiber syndrome
- Myofascial pain syndrome
- Chronic pain syndrome
- Fibromyalgia