Fascia Is Able to Actively Contract and May Thereby Influence Musculoskeletal Dynamics: A Histochemical and Mechanographic Investigation.

Fascial tissues form a ubiquitous network throughout the whole body, which is usually regarded as a passive contributor to biomechanical behavior. We aimed to answer the question, whether fascia may possess the capacity for cellular contraction which, in turn, could play an active role in musculoskeletal mechanics. Human and rat fascial specimens from different body sites were investigated for the presence of myofibroblasts using immunohistochemical staining for α-smooth muscle actin ( 31 donors, 20 animals).

Strain hardening of fascia: static stretching of dense fibrous connective tissues can induce a temporary stiffness increase accompanied by enhanced matrix hydration.

This study examined a potential cellular basis for strain hardening of fascial tissues: an increase in stiffness induced by stretch and subsequent rest. Mice lumbodorsal fascia were isometrically stretched for 15 min followed by 30 min rest (n=16). An increase in stiffness was observed in the majority of samples, including the nonviable control samples.

Quantifying collagen type in mature burn scars: a novel approach using histology and digital image analysis.

Using Herovici staining and digital image analysis, we have studied the collagen subtype and fiber orientation in mature burn scars. These techniques have shown mature burn scars to have increased type I/type III collagen ratios compared with normal skin. Additionally, the collagen orientation of burn scars has been shown to be thickened, tightly packed, and lacking the "basket weave" appearance of normal skin specimens.

Passive muscle stiffness may be influenced by active contractility of intramuscular connective tissue.

The article introduces the hypothesis that intramuscular connective tissue, in particular the fascial layer known as the perimysium, may be capable of active contraction and consequently influence passive muscle stiffness, especially in tonic muscles. Passive muscle stiffness is also referred to as passive elasticity, passive muscular compliance, passive extensibility, resting tension, or passive muscle tone. Evidence for the hypothesis is based on five indications: (1) tonic muscles contain more perimysium and are therefore stiffer than phasic muscles; (2) the specific collagen arrangement of the perimysium is designed to fit a load-bearing function; (3) morphological considerations as well as histological observations in our laboratory suggest that the perimysium is characterized by a high density of myofibroblasts, a class of fibroblasts with smooth muscle-like contractile kinetics; (4) in vitro contraction tests with fascia have demonstrated that fascia, due to the presence of myofibroblasts, is able to actively contract, and that the resulting contraction forces may be strong enough to influence musculoskeletal dynamics; (5) the pronounced increase of the perimysium in muscle immobilization and in the surgical treatment of distraction osteogenesis indicates that perimysial stiffness adapts to mechanical stimulation and hence influences passive muscle stiffness.