Effects of Low-Level Laser Therapy and Eccentric Exercises in the Treatment of Recreational Athletes with Chronic Achilles Tendinopathy

Abstract

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/cm2 and 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.