Several factors contribute to muscle hypertrophy, including resistance training, nutrition, and hormonal responses. Engaging in consistent strength training with progressive overload stimulates muscle fibers, leading to growth. Adequate protein intake is vital, as it supports tissue repair and promotes muscle synthesis. Hormones like testosterone and growth hormone also play essential roles in muscle development. Additionally, sufficient rest and recovery allow muscles to adapt and grow following exercise. Overall, a combination of effective training, nutritional support, and hormonal balance is crucial for optimizing muscle hypertrophy.