It comes from the sport of track and field, specifically the high jump and the pole vault events.

这个习语源于田径运动，特别是跳高和撑杆跳高项目。

Edwards cleared 18 feet in the pole vault.

【clear】爱德华兹在撑竿跳高中跃过了 18 英尺的高度。

He was fired because he practised the pole vault when he was on point duty.

他是值勤时练撑杆跳因此被解雇了。