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to brace one's legs; to stand firm; to plant one's feet (firmly on the ground)
to hold out; to persist; to make an effort; to exert oneself
最後まで踏ん張った彼を賞賛した。
I admired him for holding on to the very end.
逆境でも彼はまだ踏ん張っている。
He is still holding firm even in adversity.
ここで踏ん張るかどうかが勝負の分かれ目だ。
Whether you hold your ground here is the turning point of the match.