Quadriceps or rectus femoris is perhaps one of the largest muscle groups in your body and should be trained with the same intensity as your biceps femoris or hamstrings. Quadriceps are extremely important for any athlete and should be trained in compound movements to maintain symmetry with your hamstrings.
Function
The function of the quadriceps or Rectus Femoris are for knee extension and hip flexion.
Origin
The origin of the quadriceps attach onto the Illiac Spine of the Ilium and the lateral, anterior and medial surface of the femur.
Insertion
The quadriceps insert onto the patellar tendon of the Tibia.
Training
Training recommendations for the quadriceps should consist of many major compound exercises such as the squat, lunge, jump squat, and deadlift.

Calves
The gastrocnemius (calf) has two heads. The medial head and lateral head.
Function
The function of the gastrocnemius is ankle plantar flexion and knee flexion.
Origin
The origin of the gastrocnemius attaches to the posterior medial condyle on the femur.
InsertionThe calf inserts onto the achilles tendon on the calcaneous.
Training
The calf can be trained more often than other muscles but keep at least 24-48 hours of rest between heavy training