The pedal is not tightened, which is actually very dangerous, because the pedal screw is generally steel and the crank is generally aluminum alloy. If you don't step on the pedal tightly, if you step on it hard, it's easy to get rid of the crank thread and the crank will be scrapped.
The price of pedals ranges from ten yuan to several hundred yuan, while that of cranks ranges from several hundred yuan to several thousand yuan. It is recommended to use an open-ended wrench numbered 15 or a professional pedal wrench from a professional repair shop to tighten the pedal.