Immediate effect of photobiomodulation therapy on Achilles tendon morphology and mechanical properties: an exploratory study

Transl Sports Med. 2019 Jul;2(4):164-172. doi: 10.1002/tsm2.78. Epub 2019 Mar 1.


Objectives: Evaluate the immediate (within 4 hours) effects of laser-induced photobiomodulation (PBM) therapy on Achilles tendon morphology and mechanical properties in healthy and pathologic tendons.

Materials and methods: Twenty people with healthy Achilles tendons and twelve people with Achilles tendinopathy participated. One Achilles tendon received PBM treatment following an established protocol and the contralateral side received a placebo treatment. Achilles tendon morphology and mechanical properties were evaluated bilaterally with ultrasound imaging and continuous shear wave elastography immediately before treatment, immediately after treatment, then 2- and 4-hours after treatment.

Results: There were no immediate effects of PBM on tendon morphology or mechanical properties when comparing the PBM-treated side and placebo-treated side within each cohort. Additionally, the effects of PBM did not differ between healthy and pathologic Achilles tendons.

Conclusion: When treated with a laser-induced PBM treatment, healthy and pathologic Achilles tendons do not have immediate (within 4 hours) changes in tendon morphology or mechanical properties. These findings suggest that PBM therapy can be administered before other clinical treatments or high-load activities.

Keywords: Elastography; Laser Therapy; Material Properties; Tendinitis; Tendinopathy; Ultrasound.