Which combination of points is designed for strengthening the leg muscles according to TCM principles?

The combination of points that focuses on strengthening the leg muscles according to Traditional Chinese Medicine (TCM) principles is KI-9 and BL-59.

KI-9, also known as "Zhubin," is located on the Kidney meridian and is often associated with the health and strength of the lower limbs. It is indicated for various conditions related to weakness, particularly in the muscles, and its function in supporting the Kidney energy contributes to better muscle strength.

BL-59, referred to as "FuJie," is situated on the Bladder meridian and is particularly influential in enhancing the function of the lower extremities. This point is recognized for its ability to support and strengthen the leg muscles, making it an essential point for treating leg weakness or pain.

Together, these two points create a synergistic effect in promoting strength and vitality in the legs, aligning perfectly with the TCM principles that emphasize the interconnectedness of organ systems and their influence on physical strength and function.

The other combinations include points that may not specifically target the strengthening of the leg muscles, focusing instead on different areas of the body or functions, thus making them less relevant to the query.