The most effective type of exercise for building muscle mass is resistance training, which includes activities like weightlifting and bodyweight exercises. By engaging in exercises that challenge muscles, such as progressive overload, individuals stimulate muscle fibers, leading to greater strength and size. Additionally, incorporating compound movements, like squats and deadlifts, can enhance overall muscle engagement. Adequate protein intake post-workout is also vital for recovery and growth. Therefore, consistency and a well-structured program are key to maximizing muscle hypertrophy.