This week we discuss tendon stress and strain. This article was a review written by one author which was published in 2022. We found the definitions provided in the article to be particularly helpful. Strain is the change in tendon length relative to normal length, while stress is the amount of force relative to the tendon (force/CSA). These describe what is happening to a tendon. Stiffness and Young's modulus are physiologic properties of a tendon. Stiffness is a change in tendon length relative to the force applied which is dependent on cross sectional area (CSA). Young's modulus is the relationship between stress and strain, which is independent of CSA (stress/strain). This review discusses a few different articles, but one of the key points we took from this is that you can increase strain on a tendon by using heavier loads or by working at a stretched position of the joint. While this review focuses on healthy populations, this could be applied to injured populations when treating patients with tendinopathy. If the goal is to try to induce tendon strain, you could explore a variety of loading options.

The abstract can be found here: https://pubmed.ncbi.nlm.nih.gov/36135039/

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