Srila Prabhupada speaks about Krishna standing in this tribhanga pose with his body bent in 3 places. There is a nice verse in Sri Caitanya-caritamrta talking about this:

"My dear friend, if you are indeed attached to your worldly friends, do not look at the smiling face of Lord Govinda as He stands on the bank of the Yamuna at Kesighata. Casting sidelong glances, He places His flute to His lips, which seem like newly blossomed twigs. His transcendental body, bending in three places, appears very bright in the moonlight."