The exercise 'sword play' with a weighted iron bar has demonstrated significant athletic gains in wrist and slap shots for hockey players and power/finesse for tennis players.

“The amount of athletic gain that we've achieved with sword play I take an iron bar like a uh you know the old uh weer dumbbell weight it'll be an iron bar about that long and I'll put maybe a two pound weight on the end and then I grab it and I do figure eights over here over here over here around there you wouldn't believe I have professional hockey players in the NHL who say wow those figure eight sword plays my wrist shot my Slap Shot have two are tennis players I've never had such power and finesse off the racket because of that Sword Play exercise”