Bhagavad Gita, Chapter 2, Verse 48

Being steadfast in Yoga, Dhananjaya, perform actions, giving up attachment, remaining unconcerned as regards success and failure. This evenness of mind, in regard to success and failure, is known as Yoga.

Show up the same way whether it goes well or falls apart. That steadiness is the practice.

Yog here isn't a physical posture, it's a state of mind. Meeting success and failure with the same steadiness is what the word describes.