Nice set up. That handle looks different than the one that you showed in your video. Make sure that when you are doing the exercises to keep track of the how much repetitions or pace in the time that you are down there. You might have more success with higher weight and partial reps. Bruce Lee experimented with that in conjuction with isometrics. Theres lots of good articals on the subject.

It pays to understand how to make things like that. You know that this idea has been around for years almost as old as bare knuckle boxing in the US.