Muscle attached only at one end?

Gastrocnemius

The gastrocnemius is a muscle in the back of the lower leg. It is one of the two muscles that make up the calf (the other being the soleus). The gastrocnemius is attached to the femur (thigh bone) at its upper end and to the Achilles tendon at its lower end. The Achilles tendon then inserts onto the calcaneus (heel bone).

The gastrocnemius is responsible for plantar flexion, which is the movement of the foot downward. It is also involved in dorsiflexion, which is the movement of the foot upward, but to a lesser extent.

The gastrocnemius is a powerful muscle, and it is capable of generating a lot of force. This is why it is important to stretch the gastrocnemius regularly to prevent it from becoming tight and causing pain.