speed bag
noun [ C ] mainly US uk/ˈspiːd ˌbæɡ/ us/ˈspiːd ˌbæɡ/ (also punching bag); (UK usually punchball)
（练习拳击时所使用的）速度球
a leather bag filled with air, hung from a frame or attached to a stand and used by boxers for training or exercise
He's like a champion boxer working the speed bag. 他就像一个拳击冠军在进行速度球练习。
The speed bag works your shoulders and your hand-eye coordination. 速度球可以锻炼肩膀，还可以锻炼手眼协调能力。
- More examples
- A young boxer pounds a speed bag against its wooden base.
- She skipped rope, learned footwork and how to hit a speed bag.
- His feet were hammering the track like a boxer's hands on a speed bag.