Verb (5-dan, る, intransitive)
1. to brace one's legs; to stand firm; to plant one's feet (firmly on the ground)
その衝撃で背後によろめいたが、なんとか踏ん張った。The impact made me stagger backward, but I managed to brace myself.
2. to hold out; to persist; to make an effort; to exert oneself
なんとか踏ん張ってたのよ。I was somehow holding on.