I would not brain hoping a kind of weighted vibration bars that Have a very grip in the center and weights on the top. You hold them in numerous positions a single handed and two handed, and transfer your hand/arms forwards and backwards with your arms in different positions https://coingenius.news/heisenberg-gets-let-off-the-hook-in-new-historical-drama-based-on-the-farm-hall-transcripts-physics-world/