Neutral Grip Pull-Up handle Overengineered

Disclaimer:
Carefully consider your material option past and print quality, test the part somewhere safe.
I am not responsible for the possible faailure of the part, I can only speak for my experience based on materials, slicer, settings...

My experience:
I am pretty light 55kg but I tried doing pull-ups with both hands on only one handle printed with the modifier and only 8% honeycomb infill out of pla+ so the design should be able to handle a pretty good load

Print Guide:

Material: I used pla+ any stiff material with good bending strength and ok toughness and fatigue life should be good. Petg could be a little bouncy because of its lower stiffness, fiber filled materials are probably best.

If you are an heavier person or add a good amount of weight, I would suggest scaling up the part to a 36-38mm distance between the 2 faces using the orca slicer scale to dimensions tool inside the measure tool

If you decide to not use the modifier take in consideration that the thickest part created by the modifier in the internal bend is 6mm thick so 14 walls at  0.45mm wall thickness

Global Print settings:
(I have a p1p .4mm nozzle)
wall thickness (internal, external, infill, pretty much all of them) 0.6mm it gives faster print time and better layer adesion 
Infill honeycomb 10-20% Increasing it a lot will not get you much strength for the added mass
Top and bottom shell 8-10 layers assuming .2mm layer height 

Modifier:

How to set it, select the second part in the objects menu and right click, change type and in the menu that will appear select modifier: 

With it selected put 100% concentric Infill