Re: "the base is shortened during the stroke"JaapvanE wrote: ↑May 2nd, 2024, 1:13 amIt does not work as you describe. In essence, the arm amd rope form the triangle, where the base is shortened during the stroke...Slidewinder wrote: ↑May 1st, 2024, 8:24 pmIn johnlvs2run's set-up (and in my described alternate iteration of his idea), the macro-geometry at the catch is an isosceles triangle. The distance between the user's shoulders form the base. The user's arms and John's handle structure form the two equal sides of the triangle. The chain connector is at the apex. During use, and under tension, an isosceles triangle is an inherently stable 2-D structure.
Thanks for my morning smile. The base of the triangle is the width of the user's shoulders, which remains constant.
I have a considerable advantage over you in this discussion. I have actually tried johnlvs2run's handle set-up, and I have also built a handle that replaces the rope in his assembly with rigid linkages (method described on pg.2 in my April 30 reply to tadpole). It has a different appearance but retains all of the geometry and functionality of his set-up. Oilite and nylon bushings are used at the pivot points. It is fitted with firm foam bicycle handgrips. I built it about 15 years ago when John and I met on this forum. I still use it. So I know that all I have written about it is empirically true.
But you don't have to build what I built. All you need is a short piece of rope, two short tubes, and a carabiner. Assemble these items as John shows in his posted photo. Two suggestions: Adjust the rope length so there is about 11" from the carabiner to the centre of the handgrip tubes. That works best for me. Also, set the tubes on the rope so that your grip is not perpendicular to your forearm, but at a slight angle. That ergonomically correct hand/wrist relationship will be maintained throughout the stroke, whether your hands are vertical, horizontal, or anywhere in-between. It is such a simple assembly. Try it. You have nothing to lose except your illusions.