What is pennate muscles?

Pennate muscles are a type of muscle fiber arrangement where the muscle fibers are oriented at an angle to the tendon, creating a feather-like or triangular shape. This muscle design allows for high force production, as more muscle fibers can be packed into a smaller space. There are two types of pennate muscles: unipennate, where the muscle fibers are oriented to one side of the tendon, and bipennate, where the muscle fibers are oriented to both sides of the tendon. Examples of pennate muscles include the gastrocnemius in the calf and the quadriceps in the thigh.