Effects of an exercise program on calf muscle characteristics in patients with Achilles tendinopathy
Physical Therapy in Sport, vol.76, pp.127-133, 2025 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 76
- Publication Date: 2025
- Doi Number: 10.1016/j.ptsp.2025.09.013
- Journal Name: Physical Therapy in Sport
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, CINAHL, MEDLINE, SportDiscus
- Page Numbers: pp.127-133
- Keywords: Exercise therapy, Muscle adaptation, Muscle hypertrophy, Silbernagel protocol, Therapeutic exercise, Ultrasonography
- Süleyman Demirel University Affiliated: Yes
Abstract
Objective in participants with Achilles tendinopathy. Additionally, it explored the relationships between muscle adaptations and functional outcomes. Design: Prospective observational study. Setting: Laboratory-based assessment. Participants: Thirty-five participants with Achilles tendinopathy completed a 16-week exercise program. Main outcome measures: Muscle EI of the medial (MG) and lateral gastrocnemius (LG) and soleus (SOL) was assessed using ImageJ. B-mode ultrasound was used to measure MGCSA, LGCSA, and SOL thickness at baseline and post-intervention. Functional outcomes included single-leg countermovement jump (CMJ), drop CMJ, and heel-rise (HR) endurance tests. Results: MGEI and LGEI significantly decreased on both symptomatic sides (p < 0.05, d = 0.5–0.8). MGCSA and LGCSA increased (p < 0.05, d = 0.3), while SOLEI and SOL thickness did not change (p > 0.05). Heel-rise work improved (p < 0.05, d = 0.4), but jump heights did not. Regression analysis showed that age, BMI, and muscle changes did not predict improvements in HR work (Adjusted R2 = 0.11, p > 0.05). Conclusions: The exercise program reduced muscle EI and increased hypertrophy but did not significantly improve calf endurance. Further research should explore how muscle adaptations affect function in Achilles tendinopathy rehabilitation.