Final answer:
The gluteal group, which includes the gluteus maximus, medius, and minimus muscles, helps to lift the leg to the back. The hamstrings also assist in this movement by moving the thigh down and back.
Step-by-step explanation:
The muscle group in the upper leg that assists in lifting the leg to the back is the gluteal group. This group includes the gluteus maximus, which is responsible for extending the femur and is the largest of the gluteus muscles, playing a key role during activities such as getting ready to kick a ball. Other muscles in this group are the gluteus medius and gluteus minimus, which lie beneath the gluteus maximus and also contribute to movements of the femur at the hip. The hamstring group, which consists of three long muscles on the back of the thigh, also plays a part in moving the thigh down and back and assists with outward twisting of the thigh and lower leg.