Closing your fist on impact

[OctoberRed]

Yes, Jack Dempsey talked about this in his book.

Closing fist on impact gives more explosion to one's shots.

He would have open hand when thrown?

[Truth Bringer]

He would have open hand when thrown?

I think it would be open slightly and relaxed when thrown, and he would close/tighten it right before impact.

It was a long time ago when I read it but the book is called Championship Fighting: Explosive punching and Aggressive Defense.