腳往回踩、身體往後退
這一家就是核心畫面本身：出力的方向反過來，但人沒有轉身。
verb · B2
To turn the pedals of a bicycle backwards instead of forwards. On some bikes this slows the bike or stops it; on others the pedals just spin and the wheel keeps rolling freely.
倒踩踏板
核心畫面
One way to hold this word: a person on a bicycle whose feet suddenly turn the pedals the wrong way. The bike is still pointing forward, the rider is still facing forward, but the effort has flipped direction. Sometimes that stops the bike; sometimes the pedals just spin and nothing happens except the noise. Everything else the word does grows out of that flipped-direction picture — feet moving back while the face stays front, and words moving back while the speaker keeps a straight face.
可以想成一個人在腳踏車上，突然把踏板往回踩。車還是朝著前面，人也還是面對前面，只有出力的方向反過來了。有時候這樣真的…更多收起
可以想成一個人在腳踏車上，突然把踏板往回踩。車還是朝著前面，人也還是面對前面，只有出力的方向反過來了。有時候這樣真的會停下來。有時候踏板只是空轉，除了聲音什麼也沒發生。這個字其他的用法，都可以看成從這個「方向反過來」的畫面長出來的：腳往後，臉還朝前；話往回收，人還一臉鎮定。From the word’s history
The source gives the word as back + pedal, which matches the picture directly: the pedalling is simply happening the other way.
來源資料寫的是 back（往後）加 pedal（踩踏板）。這跟畫面完全對得上：踩還是那個踩，只是方向反過來。
Wiktionary entry for backpedal (source_ref kaikki:3f6f69a190036ae4:1041463625): 'From back + pedal.'
Two branches
把說出口的話往回收
同樣是往後，只是退的不是身體，而是先前表過的態度。
verb · C1
To take back or soften something you said or promised earlier, usually after people react badly to it. You move away from the strong position you took, whether or not you say you were wrong.
改口退縮