Tendon Pain? Why rest is the worst thing you can do

Let’s explore and gain a thorough understanding of tendon pain and how rest is the worst thing you can do. This article will give the reader a greater knowledge base regarding the anatomy of a tendon, how dysfunction can occur and why resting the tendon is a suboptimal approach to treating the issue.

So, I’m curious… what is a tendon and what does it comprise of?

Tendons are strong, cord-like connective tissue structures (like rope) that connect muscle to bone. They transmit the force of a muscular contraction to the skeletal system, while withstanding tension. Tendons are strong and durable, but also flexible because they can stretch and recoil without rupturing. The extensibility of tendons means that they absorb much of the force generated by muscle contractions as well as minimize energy consumption during locomotion (ability to move from one place to another).

A tendon is made of dense regular connective tissue, whose main cellular components are special fibroblasts called tendon cells (tenocytes). Tendon cells synthesize the tendon’s extracellular matrix, which abounds with densely packed collagen fibers. Healthy tendons are white in colour and have a fibroelastic structure. Within the extracellular network, tenoblasts and tenocytes constitute about 90% to 95% of the cellular elements of tendons (1).

Extracellular matrix: The dry mass of normal tendons, which is 30–45% of their total mass, is made of:

60–85% collagen

60–80% collagen I

0–10% collagen III

2% collagen IV

Tendon injury, dysfunction and pain explained:

Tendons are subject to many types of injuries. There are various forms of tendinopathies or tendon injuries due to overuse. These types of injuries generally result in inflammation and degeneration or weakening of the tendons, which may eventually lead to tendon rupture. Tendinopathies can be caused by several factors relating to the tendon extracellular matrix (ECM), and their classification has been difficult because their symptoms and histopathology often are similar. (2)

Tendinopathy (pain and dysfunction in tendon) defined as a failed healing response of the tendon, with haphazard proliferation of tenocytes, intracellular abnormalities in tenocytes, disruption of collagen fibers, and a subsequent increase in non-collagenous matrix. (3)

The dysfunction and pain are associated with overuse in and around the tendon and is characterized with pain, reduced function and exercise intolerance.

The cause of tendinopathy has been linked to the repetitive energy storage and release with excessive compression. The quantity, intensity and frequency of this load are unknown, as it can differ from person to person. Two components contribute to this, extrinsic and intrinsic factors (which can include a person’s’ biomechanics, body composition, age, gender etc). (4)

Types of tendinopathy (5) include:

Tendinosis:
Non-inflammatory injury to the tendon at the cellular level. The degradation is caused by damage to collagen, cells, and the vascular components of the tendon, and is known to lead to rupture. Observations of tendons that have undergone spontaneous rupture have shown the presence of collagen fibrils that are not in the correct parallel orientation or are not uniform in length or diameter, along with rounded tenocytes, other cell abnormalities, and the ingrowth of blood vessels.

Other forms of tendinosis that have not led to rupture have also shown the degeneration, disorientation, and thinning of the collagen fibrils, along with an increase in the amount of glycosaminoglycans between the fibrils.

Tendinitis: Degeneration with inflammation of the tendon as well as vascular disruption.

Paratenonitis: Inflammation of the paratenon, or paratendinous sheet located between the tendon and its sheath.

Tendon injury – Risk Factors:

• Hormone Replacement Therapy
• Contraceptive medication
• Diabetes
• Obesity
• High adiposity in lower limb tendinopathies
• Lack of range of movement Inflexibility
• Strength imbalance
• Poor vascularity
• Altered lower limb biomechanics

Tendon recovery, rest is best, yes? NO, here is why.

Failed healing and tendinopathic features have been associated with chronic overload, but the same histopathological characteristics also have been described when a tendon is unloaded: stress shielding seems to exert a deleterious effect. Unloading a tendon induces cell and matrix changes like those seen in an overloaded state and decreases the mechanical integrity of the tendon. (6) In chronic tendon injuries, mechanical loading has also been shown to stimulate fibroblast proliferation and collagen synthesis along with collagen realignment, all of which promote repair and remodelling. (7)

To further support the theory that movement and activity assist in tendon healing, it has been shown that immobilization of the tendons after injury often has a negative effect on healing. In humans, collagen fascicles that are immobilized have shown decreased tensile strength, and immobilization also results in lower amounts of water, proteoglycans, and collagen crosslinks in the tendons. (8) In conclusion, tendon injuries are complicated and are multifactorial. The content above highlights the current science and understanding with regards to tendon structure, dysfunction and injury recovery. The bottom line is that resting your tendon injury is completely inappropriate and should be avoided. A controlled, tailored and appropriately loaded exercise regime is best in which anyone with a tendon injury should consult a health professional to start their rehabilitation.

References:

Kannus P, Jozsa L, Jarvinnen M. Basic science of tendons. Principles and practice of orthopaedic sports
medicine. Philadelphia: Lippincott Williams and Wilkins; 2000. p 21-37.

Sharma, P. M., N. (2006). “Biology of tendon injury: healing, modeling and remodeling”. Journal of
Musculoskeletal and Neuronal Interactions. 6 (2): 181–190

Maffulli et al. Novel Approaches for the Management of Tendinopathy. J Bone Joint Surg Am. 2010;92:2604-2613.
doi:10.2106/JBJS.I.01744

Maffulli N, Sharma P, Luscombe KL. Achilles tendinopathy: aetiology and management. Journal of The Royal
Society of medicine 2004;97:472–476

Maffulli, Nicola; Wong, Jason; Almekinders, Louis C (2003). “Types and epidemiology of tendinopathy”. Clinics
in Sports Medicine. 22 (4): 675–692. doi:10.1016/s0278-5919(03)00004-8

Cook JL, Purdam CR. Is tendon pathology a continuum? A pathology model to explain the clinical presentation
of load-induced tendinopathy. Br J Sports Med. 2009;43:409-16

Wang, J. H. C. (2006). “Mechanobiology of tendon”. Journal of Biomechanics. 39 (9): 1563–1582. doi:10.1016/j.jbiomech.2005.05.011

Sharma, P. M., N. (2006). “Biology of tendon injury: healing, modelling and remodelling”. Journal of
Musculoskeletal and Neuronal Interactions. 6 (2): 181–190

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