Importance of strength training for tendons

Tendons play a critical role in transmitting forces from muscles to bones, enabling efficient movement and locomotion. The ability of tendons to adapt to mechanical load is essential for their proper functioning and resistance to injury. In the 2022 article by Lazarczuk, the author explores how  healthy lower limb tendons adapt to strength training . This summary aims to provide an overview of the key findings and insights presented in the article.

What happens in the tendon with strength training ?

 

Regular loading stimulates the alignment and realignment of collagen fibers along the lines of force, enhancing the tendon’s ability to resist tensile forces and improving its mechanical properties. Moreover, exercise-induced mechanical loading promotes the development of a more organized hierarchical structure within tendons.

Not only does resistance training affect the collagen quality and structure but it also influences another important component of the tendon , the  extracellular matrix (ECM) components. The ECM of tendons consists not only of collagen fibers but also  proteoglycans, and elastin.

strength training influences the synthesis, organization, and turnover of these tendon components. Increased loading can lead to an increase of collagen production, resulting in the remodeling and strengthening of tendon tissue.

Mechanical Properties and Adaptation

Its not only the structure of the tendon that is positively affected by strength training. The  mechanical properties of tendons that make them greater shock absorbers and almost have a spring like quality are affected by training as well.   Regular exercise, such as strength training , running, hopping  or physical activity, stimulates adaptive responses that enhances these spring like qualities.

How long does it take for tendon to get stronger ?

The article highlights that the time course and magnitude of tendon adaptation depends on the specific mechanical stimuli applied. Acute loading elicits immediate responses such as increased blood flow and biochemical changes which can have a pain relieving effect in the painful tendon.

However, long-term changes, including collagen synthesis and remodeling, requires sustained loading over an extended period. The magnitude of adaptation is influenced by factors such as the intensity, ( 70% of 1 rep max strength seems to be the magic number), frequency, and duration of mechanical loading. It has been proposed that it takes up to 3 months in healthy tendon to see a change in the the collagen synthesis and remodeling

Understanding these factors has important clinical implications. Rehabilitation and exercise programs can be designed to optimize tendon adaptation and enhance recovery from tendon injuries. Gradual progression of mechanical load, appropriate exercise selection, and load management are crucial to stimulate positive adaptations without overloading the tendon, which could lead to injury.