Here is a brief look at how to break an attackers arm with your knee. From the Tai Chi move: Monkey Retreats.
http://www.clearstaichi.com/tai-chi-dvds/combat-tai-chi-vol-7-monkey-retreats...
For more on how to fight with Tai Chi including Quick & Effective Street Applications, Poison Hand, Dim Mak & Stamping, Fa Jing, How to Destroy a Knife wielding attacker, Ji (Press,) Rollback (Lu,) Vicious Knees & Elbows, and much more check out the "Clear's Combat Tai Chi Vol 7: Monkey Retreats"
@josh808m Remember the move doesn't stop so your arm continues back while there arm gets stopped by the knee creating the break. Done correctly you are catching the arm at an angle that makes it very difficult for the person to let go though you may need to play with the app (carefully) at home to get a feel for it. Remember that the more correct your structure and body state are the more effective the app will be.
CombatTaiChi 1 month ago
Looks like you're just hitting his arm with your knee but very little chance of breaking.
josh808m 1 month ago