Natyashastra
नमनोन्नमनात्पार्ष्णेर्मुहुः स्यादूरुकम्पनम् । गच्छेदभ्यन्तरं जानु यत्र तद्वलनं स्मृतम् ॥ २५३॥
Raising and lowering the heels again and again constitutes Kampana (shaking) of the thighs. When the knee moves inward during walking, it is called Valana (turning).
english translation
namanonnamanAtpArSNermuhuH syAdUrukampanam । gacchedabhyantaraM jAnu yatra tadvalanaM smRtam ॥ 253॥
hk transliteration by Sanscript