LESS IS MORE

Effects of Low-Level Laser Therapy and Eccentric Exercises in the Treatment of Recreational Athletes With Chronic Achilles Tendinopathy.
Stergioulas et al Am J Sports Med. 2008.

This study demonstrates that a 30mW 830nm laser with a 0.5cm2 beam (= only 60mW/cm2 intensity) applied over 6 points along the Achilles tendon for 180 seconds per point accelerates recovery from chronic Achilles tendonitis.

Note the relatively large spot size of this 30mW laser (hence rather low intensity), and long treatment times used.

All the dose rate studies that I have read indicate that intensities in the tens of mW/cm2 range work best for anti inflammatory and healing effects in superficial tendon injuries, whereas the higher intensities (1,000 mW/cm2) are probably only suitable for analgesic effects.

Effects of Low-Level Laser Therapy and Eccentric Exercises in the Treatment of Recreational Athletes With Chronic Achilles Tendinopathy.
Apostolos Stergioulas, Marianna Stergioula, Reidar Aarskog, Rodrigo A B Lopes-Martins, and Jan M Bjordal
Am J Sports Med. 2008.

Background: Eccentric exercises (EEs) are recommended for the treatment of Achilles tendinopathy, but the clinical effect from EE has a slow onset.
Hypothesis: The addition of low-level laser therapy (LLLT) to EE may cause more rapid clinical improvement.
Study Design: Randomized controlled trial; Level of evidence, 1.
Methods: A total of 52 recreational athletes with chronic Achilles tendinopathy symptoms were randomized to groups receiving either EE + LLLT or EE + placebo LLLT over 8 weeks in a blinded manner. Low-level laser therapy (λ= 820 nm) was administered in 12 sessions by irradiating 6 points along the Achilles tendon with a power density of 60 mW/cm2and a total dose of 5.4 J per session.
Results:The results of the intention-to-treat analysis for the primary outcome, pain intensity during physical activity on the 100-mm visual analog scale, were significantly lower in the LLLT group than in the placebo LLLT group, with 53.6 mm versus 71.5 mm(P= .0003) at 4 weeks, 37.3 mm versus 62.8 mm (P= .0002) at 8 weeks, and 33.0 mm versus 53.0 mm (P= .007) at 12 weeks after randomization. Secondary outcomes of morning stiffness, active dorsiflexion, palpation tenderness, and crepitation showed the
same pattern in favor of the LLLT group.
Conclusion: Low-level laser therapy, with the parameters used in this study, accelerates clinical recovery from chronic Achilles tendinopathy when added to an EE regimen. For the LLLT group, the results at 4 weeks were similar to the placebo LLLT group results after 12 weeks.