Tā zhàn zài dān tuǐ shàng, chàdiǎn shīhéng shuāidǎo.
He stood on one leg and nearly lost his balance and fell.
Tips
usage
失衡 is used both literally (losing physical balance) and figuratively (imbalance in economics, ecology, power, etc.). The noun form 失衡 is also used: 贸易失衡 (trade imbalance).