Kāihétiào shì ránzhī xiàolǜ hěn gāo de yǒuyǎng dòngzuò.
Jumping jacks are a highly effective fat-burning aerobic exercise.
Tips
memory
Literally 'open-close-jump' — describes the motion exactly: legs and arms 开 (open out) on the jump, 合 (close together) on landing. Easier to remember than the English name once you visualize it.
culture
A staple of HIIT (高强度间歇训练) routines pushed by domestic fitness influencers like 周六野 Zoey and 帕梅拉 (Pamela Reif, dubbed 'foreign Liu Genghong' in China). You'll see it constantly in workout videos on Bilibili and Xiaohongshu.