Thursday, June 16, 2011

The Extended Fascial Paradigm and its Implications in Athletic Conditioning: Part 2

One of the primary characteristics for any functionally relevant tissue to have is the ability to deliver some form of sensory stimulus. The specific tissue will need to be sensitive, not only the environment, but to its relative position and status. Fascia is highly innervated and is a very powerful sensory organ (4).

Golgi Tendon Organs
Senses extension and triggers appropriate nervous system reaction (firing rate)
Sensitive to muscle contraction
Will restrict motion in risk of failure
Will decrease tonus in motor fibers as a result of stimulation
10% found in tendon
90% found in muscular portion

Pacini Receptors
Responds to compressive velocity or vibration stimulations
Increases local proprioceptive attention
Variable morphology

Ruffini Receptors
Responds to lateral stretch
Increase local proprioceptive attention
Inhibition of sympathetic activity

Interstitial Receptors
High and low threshold pressure units
Increase local proprioceptive attention
Stimulation of high threshold pressure units may induce pain and thus increase plasma extravasation

The fact that fascia is highly innervated suggests that, by definition, it is able to respond and adapt to stimulus. This adaptation will be in the form of a local response or, to be precise, remodelling. Fascia will remodel by means of mechanotransduction. The term mechanotransduction is defined as the molecular response of cells to mechanical input. Many physiological responses have been observed in response to force: (5)

• In cartilage, cells secrete more glycosaminoglycan-rich matrix when stimulated with force
• In the lining of the cardiovascular system, endothelial cells change shape and properties in the presence of altered shear stress
• Cardiomyocytes get larger and generate more force when subjected to a greater demand
• Bone density increases (more osteoblast action) in response to elevated stress levels
• Tendons and fascia mechanical properties (size and strength of fibers) respond to stress

The process of mechanotransduction will solicit what is called the piezoelectric phenomenon within the targeted tissues.

• Fascia is primarily made up of collagen proteins
• Collagen has dipole characteristics (positive and negative ends)
• Deformation of tissue causes alterations in the electrical potential throughout
• Deformation creates a measurable electrical field
• This field stimulates fibroblast activity to produce new collagen deposits

As with all physiological tissues within the body, fascia will respect Wolf’s Law.

• If a tissue is submitted to more demanding conditions it will remodel to meet the demands more efficiently
• If a tissue is submitted to less demanding conditions it will resorb

This process is governed by the tissue mechanotransduction which, in turn, is governed by the stress (force) input. Therefore the mode of stress applied (speed of application) and the amount (total force) is essential to the resultant adaptation. In order to achieve positive long term adaptation, the application of the stimulus must be relatively slow and repetitive.

• Induce multiple deformations / impacts of 1-2% of initial tissue length (60 minutes)
• Creates permanent remodeling without harming health of membrane (6).

1 comment:

  1. Thanks for deepening my understanding of fascia and how it relates to my fitness programming.