Points The toes
When the Deltoid contracts the humerus abducts.
Quads
When the subscapularis muscle contracts concentrically, it performs internal rotation of the shoulder joint. This movement involves rotating the arm inward toward the midline of the body.
The muscle that contracts when the leg is extended at the knee is call the gastrocnemius muscle
When the gluteus maximus contracts concentrically, hip extension occurs. This means the thigh moves backward, bringing the leg into alignment with the body.
It contracts
The gastrocnemius muscle is located with the soleus in the posterior (back) compartment of the leg. It is associated with the "bulge" in the calf muscle.
When the shank is flexed as in walking, the gastrocnemius muscle is contracted. This allows for plantar flexion of the foot, pushing the body forward during the walking motion. The gastrocnemius muscle plays a critical role in the propulsion phase of walking.
The gastrocnemius is stimulated by a branch of the sciatic nerve called the tibial nerve. This causes contraction and produces plantar flexion of the foot. When a person stands on their "tippy toes" that is plantar flexion. This is a function of this nerve.
The flexor would be the hamstring, and gastrocnemius, which bend/flex the knee. The quadriceps, are extensors, which straighten/extend the knee.
The gastrocnemius, soleus and peroneus longus muscles insert at the heel (calcaneus) by way of the Achilles (calcaneal) tendon.
Gastrocnemius