Before talking about the pathology that can cause us a tendon We must know what is and how it behaves.
What is tendon
He tendon It is a structure of connective tissue that unites the muscle with the bone and whose function is to transmit the forces generated by the first to the second. This force may or may not generate joint movement depending on the resistance to be overcome and the newtons exerted to do so.
He tendon We can divide it into 3 regions:
- Union osteotendinous (where bone and tendon join).
- Union myotendinous (where the muscle and tendon join).
- Own body of the tendon (Middle zone, between the two previous ones).
It is composed of a extracellular matrix (contains 68% of water) formed by:
- Collagen fibers (60-80%).
- Elastin (2%).
- Fundamental Substance.
- Elements of conjunction.
Its main cell It is the tenocyte, which responds to mechanical forces, deforming and adapting to new situations depending on these forces. The tendon is capable of specializing depending on the activity to which it will be subjected.
How the tendon behaves
He tendon It is designed to withstand tension forces and of stretching (has a resistance to traction greater than steel) and is not able to withstand compression forces and shearing.
When applying a tensile force to the tendon, this one suffers a initial elongation and responds with resistance, progressively deforming. As the pressure increases, tensile force he tendon It has to present greater resistance. When the force to which it is subjected is very high, it ends up breaking.
At rest the tendon fibers are intertwined and as the tendon tightens around a 2%, these fibers realign themselves to support the load. When the tension is removed the fibers are able to recover their original shape and length. However, if the tendon is stretched more than a 4% may appear damage in it in the form of partial break, until overcoming the 8% of stretching that we would talk about a total breakup.
This is because the tendon is a viscoelastic fabric and, as we have previously mentioned, it is able to stretch and return to its original position (elasticity); but once a certain tension has been overcome, it is no longer able to resume it (goo), where it will begin to fail.
This viscoelastic capacity It is essential for the tendon to transmit the force during the motion through the energy accumulated in the tendon itself, as well as serving as a shock absorber to protect the muscle and to bone of the injury.
TENDON PATHOLOGY
As a general rule, the tendon it's a tissue that is injures by overuse, although sometimes the origin of the injury is a stranger. Therefore we can say that it is more common in people who practice sport.
When the tendon is subjected to continuous tension for a period of time, it is not able to withstand it and begins to degenerate; But the tendon is not only injured due to these repeated tensions but when it is subjected to compression forces (“impingement”).
In addition, there are a number of risk factors that predispose to injury (genetic, nutritional, emotional...); but it is above all the eccentric exercise the one that usually causes the most damage to this structure.
Types of tendinopathies:
- REACTIVE TENDINOPATHY More acute stage. No major changes in the tendon. “Too much Too soon”. Improves with decreased activity.
- FAILED REPAIR TENDINOPATHY Once reactive tendinopathy has not been overcome, the tendon enters this stage, where, following sustained stimulation over time, a series of histopathological changes occur, such as disruption of the matrix and increased destruction of collagen. It improves with a treatment plan based on adapted exercise.
- DEGENERATIVE TENDINOPATHY to Apoptosis (cell death).
TREATMENT
Tendon treatment is complex, but in most cases it is a matter of a good approach over time.
From Evolution Madrid We consider the keys to success to be:
- Load management: PainIntensity, Frequency, Periodization.
- Rest does not cure: Destructuring of the tendon. The tenocyte It has to move to start collagen synthesis.
- Re-adapt the tendon in all directions, not only in the sporting gesture.
- The type of contraction is not relevant but we can start with isometric exercise because it is capable of activating the pain inhibition pathways. Progress towards concentric and eccentric exercise.
- Not recommended plyometric training in the lower limbs, during the first few weeks.
Literature:
– Basas García, A. Analysis of the effects of an electrostimulation protocol and eccentric, isometric and concentric exercises on pain and functionality in the treatment and rehabilitation of patellar tendinopathy or jumper’s knee. [Thesis]. Madrid. Universidad Complutense de Madrid; 2017. 181 p.
