stamp feet
跥 centers on stamping the feet, a forceful downward motion with the foot.
跥 combines 足 (foot) with 朶, which likely contributes a phonetic element. The exact historical development is uncertain.
The left side 足 means foot, and the right side 朶 looks like a heavy object (木 with extra strokes). Imagine a foot bringing down a heavy stamp.
For タ, picture stamping your foot to the beat of a taiko drum: ta -> タ, and the foot stamps down hard.