Effectiveness of eccentric calf muscle exercise therapy in patients with chronic midportion Achilles tendinopathy: a randomized controlled trial.

OBJECTIVES: Achilles tendinopathy is a common injury that reduces quality of life and function. Eccentric calf muscle exercise therapy (EET) is the most frequently used exercise type in clinical trials. This study aimed to compare the short-term effectiveness of EET to sham exercise therapy (upper extremity strength training, UET) in patients with chronic midportion Achilles tendinopathy. DESIGN: A randomized controlled trial. METHODS: Adults with clinically diagnosed Achilles tendinopathy were assigned to either EET or UET. The intervention consisted of daily calf-muscle or upper limb strengthening exercises for 12 weeks. The primary outcome was the change in the Victorian Institute of Sports Assessment-Achilles (VISA-A, 0-100) score over 12 weeks. Treatment effects were analyzed using linear mixed models, based on intention-to-treat. RESULTS: Sixty-eight participants (34 EET, 34 UET) were included (mean age: 52 ± 10 years; 40% female). Ten participants (15%) were lost to follow-up. After 12 weeks, the mean VISA-A score improved by 10 points (95% confidence interval [CI], 2-22) in the EET group and by 6 points (95% CI, 2-15) in the UET group. The adjusted between-group difference was not significant (4 points; 95% CI, -7-15). CONCLUSIONS: In patients with chronic midportion Achilles tendinopathy, no significant difference in symptom improvement was observed between unsupervised home-based EET and UET after 12 weeks. These findings suggest limited short-term effectiveness of EET as an unsupervised home-based exercise program.