The quadriceps muscles, also known as quads, are a group of muscles located at the front of the thigh. They are responsible for various movements such as kicking, running, jumping, and walking. The quadriceps femoris is the main muscle in this group and is the largest muscle in the human body. It consists of four individual muscles: the rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius. These muscles work together to extend the knee and stabilize the patella, or kneecap. The quadriceps muscles also play a crucial role in activities such as walking, running, jumping, and squatting. They are voluntary muscles, meaning they are under conscious control, and are vulnerable to injuries such as strains and contusions.