In-vivo manipulation of muscle shape and tendinous stiffness affects the human ability to generate torque rapidly

What is the central question of this study? What are the determinants of the muscle belly gear, and how does it affect the torque rise? What is the main finding and its importance? Change in muscle thickness of the gastrocnemius medialis is related to variations in the belly gear. Belly gear shows a key role in the rise of the muscular torque and rate of torque development (RTD). Besides, the increase of the tendinous tissue stiffness could increase the torque rise as well, and in turn, the RTD. However, changes in the tendinous tissue stiffness showed no effects on muscle fascicle behaviour, suggesting a possible uncoupling between muscle and tendon mechanical properties.