Myostatin deficiency blunts mechanical adaptation of soleus muscle to overload

The aim of this study was to determine the impact of myostatin deficiency on the mechanical and contractile adaptations of the soleus muscle to functional overload (FO). Using a cross-sectional design, we compared the control and FO soleus muscles of myostatin-deficient (BEH^cc) and myostatin-functional (BEH⁺⁺) mice. FO was induced by 28 days of gastrocnemius ablation. Soleus muscles were isolated and subjected to an isometric-eccentric contraction protocol to analyse contractile performance and tissue mechanical behaviour. FO significantly increased muscle mass, tetanic force, and stiffness, in BEH⁺⁺ mice (p < 0.05), but not in BEH^cc where absolute force was even reduced (p < 0.05). These findings indicate that myostatin plays an important role in successful skeletal muscle adaptations and preservation of muscle function under chronic loading.