Final answer:
The gluteus maximus and hamstrings contribute to hip extension, with other muscles in the gluteal region assisting in leg and thigh movements. The pelvic girdle's limited range of motion ensures stability and efficient energy usage during walking and posture maintenance. The large muscles of the hip and thigh are essential for the body's stabilization and movement.
Step-by-step explanation:
The question pertains to the anatomy of the hip extension and the muscles involved, mainly the gluteus maximus and the hamstrings. These muscle groups play crucial roles in various movements such as raising the knee at the hip during a knee attack, twisting the thigh outward, and maintaining posture while bending over. The gluteal group, which includes the gluteus maximus, medius, and minimus, is largely responsible for these actions. The posterior compartment of the thigh, comprising the hamstring group with its three long muscles, enables movements like lifting the back of the lower legs toward the buttocks and assisting with the downward and backward motion of the thigh.
Additionally, the gluteus medius and minimus aid in abducting the femur at the hip, while the gracilis muscle is involved in adducting the thigh and flexing the leg at the knee. If the pelvic girdle had a range of motion similar to the pectoral girdle, walking and maintaining balance would become more energy-intensive due to the reduced stability of the femurs within the pelvis. The large and powerful muscles of the hip and thigh are designed to stabilize and move the femur, ensuring efficient posture and motion for the human body.