I couldn't, it's a strength to bodyweight thing. Rockjocks are very lean, and strong. There's a 19C photo of some pioneers in Scotland who used a snooker table to train... hands on the table, feet up the wall, hand walk around the table!
TBH if it's hand to forearm strength you want, all you need is a stick; swing it up vertically as a sword, stopping the downward swing at waist level by tightening your two hands with a slight inward motion. Develops wrist and forearm strength.
People (kendoka / aikidoka) who have practiced suburi for years have an intense grip when they want to apply it.