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). You'll see it constantly in workout videos on Bilibili and Xiaohongshu.