I can't find the specific video 😭 UPDATE: https://vm.tiktok.com/ZGdxv9Q5E/ But we focused on this last training with @Jürgen Paulus . He has a strong body, but when we looked at the punch mechanics, his heel was lifting of the ground. Externally it looked good, but internally his glutes and leg muscles weren't adding power to his strike. So for a stronger gyaku zuki, we focused on the cues of sinking his pelvis forward and flexing his glutes. Ironically this also creates the same heel lift, but the entire body becomes a spear thrusting the fist forward. Not sure if this makes sense without any visual aid 😅 Let me know...