To push off with the feet to launch into a jump or take-off (as in track jumping, ski jumping, diving).
長距離走の最後で踏み切って一気にスピードを上げた。
At the end of the long run he pushed off and sped up all at once.
スキージャンプ選手は踏み切るタイミングがとても重要だ。
The timing of the push-off is very important for ski jumpers.
ダイビングの前に板をしっかり踏み切ってから飛び込む。
Before diving, you firmly push off the board and then plunge.
To make up one's mind to take the plunge or start something; to decide to take action.
転職することに踏み切るには、準備が必要だ。
You need preparation before you take the plunge and change jobs.
彼はついに大学院への進学に踏み切った。
He finally decided to go on to graduate school.
新しい事業を始めるかどうか、家族会議の後で踏み切った。
After a family meeting, they decided to go ahead and start the new business.
In sumo, to step out of the ring (to step off the dohyo).
押し合いの途中で力士が踏み切ってしまい、取組に敗れた。
During the pushing bout the wrestler stepped out and lost the match.