The plantaris muscle is a thin, elongated muscle located in the back of the lower leg. It originates at the lower end of the femur (thigh bone) and inserts into the Achilles tendon. The plantaris muscle is one of the smallest muscles in the human body, and is often considered to be vestigial, meaning that it no longer serves any important function.

The main function of the plantaris muscle is to help flex the knee joint and plantarflex (point downwards) the ankle joint. This can help with activities such as walking, running, and jumping. However, due to its small size and lack of strength, the plantaris muscle is not very important for these movements, and can be easily compensated for by other muscles in the leg.

There are no specific exercises that target the plantaris muscle, as it is not considered to be an important muscle for strength or athletic performance. However, exercises that involve flexing the knee joint and plantarflexing the ankle, such as calf raises and leg presses, may help to strengthen the plantaris muscle to a small extent.