Think rugby or American football. A tackle is when one player gets hit by another player. A player may be hit so hard that they have difficulty breathing for a few seconds.
I was winded once when I was a child. I climbed up a tree, promptly fell out of the tree and landed hard on my back. It winded me. I couldn't catch my breath. In other words, I had difficulty breathing for a few seconds.
I hope these examples help!